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Oasis montaj v 9.4 Course Manual
The software described in this manual is furnished under license and may only be used or copied in accordance with the terms of the license. OM.cm.2018.10 Manual release date: Monday, October 22, 2018. Please send comments or questions to [email protected] © 2018 Geosoft Inc. All rights reserved. Geosoft is a registered trademark and Oasis montaj is a registered trademark of Geosoft Inc. Other brand and product names mentioned herein are properties of their respective trademark owners. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form, or by any means, electronic, mechanical, photocopying, reading, or otherwise, without prior consent from Geosoft Inc. Windows™, and Windows NT are either registered trademarks or trademarks of Microsoft Corporation. Geosoft Incorporated Queen’s Quay Terminal 207 Queen’s Quay West Suite 810, PO Box 131 Toronto, Ontario M5J 1A7 Canada Tel: (416) 369-0111 Fax: (416) 369-9599 Website: www.geosoft.com E-mail: [email protected]
Table of Contents
Table of Contents
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Introduction: Oasis montaj
1
Module 1: Working with Databases
3
Lesson 1.1 Creating a Project and Importing Data Project Explorer To edit the display of a channel:
5 12
Lesson 1.2 Defining the Coordinate System
18
Lesson 1.3 Georeferencing Your Data
24
Opening a Map Lesson 1.4 Working with Database Tools
28 35
Changing Lines
46
Profile Scaling
46
Axis Direction
47
To create a distance channel:
48
Lesson 1.5 Working with Array Data Array Data .....................
52 52
To import an ASCII file into an array database:
52
To assign the coordinate system
55
To add depth information to an array:
56
To Visualize Array Data
57
Lesson 1.6 Filtering Databases and Grids To display the original mag data on line 61: Module 2: Creating Maps
61 61 69
Lesson 2.1 Creating a Map
70
Lesson 2.2 Creating Contours
93
Lesson 2.3 Using CAD Tools
99
Lesson 2.4 Using Geosoft Seeker
102
Without an Open Map:
103
With an Open Map:
103
To use the Seeker tool
103
Download Properties Module 3: Creating Gridded Data
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104 107
Lesson 3.1 Gridding Using the Bi-Directional Method
109
Lesson 3.2 Gridding Using the Minimum Curvature Method
116
Lesson 3.3 Gridding Using the Kriging Method
123
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Table of Contents
Module 4: Working with Sections Lesson 4.1 Creating Sections from Array Data
130
Lesson 4.2 Creating Stacked Sections from Array Data
133
To create a stacked section map from array data: Lesson 4.3 Creating Sections from a Plan Map To create a section from a plan map: Lesson 4.4 Import Section Grids into a 3D View To import section grids into a 3D view Module 5: Creating a 3D Map Lesson 5.1 3D Viewer
133 136 136 139 139 143 144
To open a 3D view and plot topography
144
Lesson 5.2 Drape Data on a Relief Surface
146
Lesson 5.3 Working with Voxels
149
To add voxel to 3D view
149
To manipulate the voxel colour distribution
150
Lesson 5.4 Clipping Voxel Extents
152
Lesson 5.5 Working with Isosurfaces
156
To create and display the isosurface: Lesson 5.6 Creating Snapshots and Animations Module 6: Wireframing Lesson 6.1 Creating a Geostring File and Adding Features Geological Interpretation and Wireframing Lesson 6.2 Digitizing Interpretations on Section Maps To prepare section maps for digitizing
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156 158 161 162 162 166 166
Lesson 6.3 Editing Geostring Files
169
Lesson 6.4 Wireframing Interpretations
173
Lesson 6.5 Sharing 3D Data
177
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Introduction: Oasis montaj Oasis montaj™ is Geosoft’s core software platform for working with large volumes of spatial data and provides the functionality required to locate, manage, visualise, manipulate, display and share spatially located Earth Science data. The Oasis montaj environment provides direct access to data contained in Geosoft Databases through a Spreadsheet window and an integrated Profile display window. The Geosoft Database is a high-performance database that provides efficient storage and access for very large spatial datasets.
About this Training Manual The Oasis montaj course manual is for use with our online On Demand Training or in a classroom setting, both are provided with a qualified Geosoft instructor. Outside of the classroom setting, you can access our Geosoft Geonet forum, to find answers to any questions you may have. Each module in this book contains a series of hands-on lessons that let you work with the software and a supplied dataset. Lessons have brief introductions followed by tasks and procedures in numbered steps. The following modules are included in this course: Module 1 - Working with Databases Module 2 - Creating Maps Module 3 - Creating Gridded Data Module 4 - Working with Sections Module 5 - Creating a 3D Map Module 6 - Wireframing
Course Data The data used in this course are contained in a folder called GODT - Target Essentials Course Data. Please copy the whole folder of data to your C:\ drive or other hard drive where you have at least 200 MB of available space.
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Oasis montaj | 1
Introduction: Oasis montaj
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Module 1: Working with Databases Module 1 has Six Lessons: Lesson 1.1 Creating a Project and Importing Data
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Lesson 1.2 Defining the Coordinate System
18
Lesson 1.3 Georeferencing Your Data
24
Lesson 1.4 Working with Database Tools
35
Lesson 1.5 Working with Array Data
52
Lesson 1.6 Filtering Databases and Grids
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Module 1: Working with Databases
Lesson 1.1 Creating a Project and Importing Data In this lesson you will: Create a project Create a new database Import data Save the project
Creating a Project Working in Oasis montaj requires an open project. An Oasis montaj project encompasses every item in your working project from the data files in your project (databases, grids, maps, 3D views, voxels, VOXI files, ArcGIS MXD files and GMSYS 3D Models), to the tools used (including auxiliary tools such as histograms, scatter plots, etc.), to the project setup including the menus you have displayed, whether you are working on a map or profile, and the state in which you left it the last time you used it. Projects are saved as (*.gpf) files. The project also controls your working folder. If you open an existing project from a folder, the system assumes that all your project files are located in the same folder. To streamline your work, as well as keep it organised, you may wish to save your project file in the same folder as the other project files you want to use. Each project you work on should have its own project (*.gpf) file. To start Oasis montaj: From the Start menu, select All Programs, then Geosoft then Oasis montaj. - ORDouble-click the Oasis montaj icon on your desktop. The Oasis montaj window opens. To create a new project: 1. Start Oasis montaj. The Oasis montaj project workspace opens and a Start up screen appears which enables you to quickly open an existing project or create a new one. 2. From the Start up screen select Create New Project. The new project window opens. 3. Locate the Geosoft Training Data folder. 4. For the project File name, enter Mt Palmer.gpf and click Save. Your project opens and several menus are added to the Oasis montaj window.
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Lesson 1.1 Creating a Project and Importing Data
Figure 1.1 Oasis montaj with an opened project
Project Explorer The Project Explorer is essentially a data and project management tool that enables you to do the following: Add new data to your project. Edit data file names. Remove data from your project, or directly from the source data folder. View and edit the properties of a dataset. Create, view and edit metadata for a dataset. Manage the menus that are displayed in the project workspace. Run individual Geosoft Executables (GXs) and record scripts. Access specialized Tools (e.g. plotting and analysis tools) that are available in some Oasis montaj extensions. The Project Explorer tool can be displayed in many different ways to suit your needs, including: "Pinned" open or unpinned (auto-hidden) so that it appears only when you hover over it with the mouse. Docked to the left or right of the project, or floating within the project workspace. Moved onto a different monitor from the project workspace. Creating a Geosoft Database The Geosoft Database is organised in lines, channels and elements. The database stores all data "elements" of a particular type in individual "channels" (or columns). Database "lines" are a collection of related "channels".
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Module 1: Working with Databases
Figure 1.2 Geosoft Database lines
Each database "line" has a line number, version number, line type, flight number (for airborne data), survey date and selection status. A database may contain any number of lines (also called groups in other applications such as drillhole plotting). If your survey data has not been collected on a line basis, such as drillhole or surface geochemistry data, you can store all data in a single line. Oasis montaj features a database compression option that enables you to reduce the file size and improve the performance of Geosoft Database files (*.gdb). You can choose either to compress for speed, compress for size or no compression at all. The type of compression you use depends on your needs. For example, you would likely compress for speed if you have a lot of hard drive space available. However, if space is limited, you may wish to compress for size. To create a new database: 1. From the Database menu, select New Database. The Create New Database dialog opens. Figure 1.3 Create New Database dialog
2. For the New database name, type mag. You can specify the Maximum lines/groups and Maximum channels/fields. The defaults are 200 and 50 respectively, but you should specify a number that is representative of the final estimated project size. This ensures that you have enough space available in your project while not consuming excessive storage space. Decreasing these values from the defaults will not enhance performance. If you have more lines and channels to import later on, you can grow the database to accommodate them by using the Grow option from the Database then Maintenance menu. 3. Click OK. The new database opens in the Oasis montaj window.
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Lesson 1.1 Creating a Project and Importing Data
Figure 1.4 New database in Oasis montaj
If you go directly to import your data before creating a database, the Import tool will prompt you to create a new database.
Importing Data into the Geosoft Database There are a number of options for importing Geosoft and third-party data formats. In this lesson you will import two types of data using different importing tools. First, you will import data in standard Geosoft XYZ format, then you will import data in CSV format. To import Geosoft XYZ format data into a database: 1. From the Database menu, select Import and then Geosoft XYZ. The Import message window opens asking if you want to import data into the current database you just created. 2. Click Yes. The Import Geosoft XYZ dialog opens. Figure 1.5 Import Geosoft XYZ dialog
3. For the File(s) to import, click the Browse button
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Module 1: Working with Databases 4. From the Geophysics folder, select mag survey.xyz and click Open. 5. On the Import Geosoft XYZ dialog, click Create Template. The Import dialog opens with the mag survey.xyz file name displayed on the dialog title bar. Figure 1.6 Import template dialog
The Import template dialog is used to specify the parameters of the channels being imported to the Geosoft Database. Key parameters to check are the Source Data Format and the Output field names. 6. Click OK. The Import template dialog closes and the Import Geosoft XYZ dialog reopens. 7. From the Import mode list, select Append. With this option, imported lines will be renamed as a new version, if a line already exists in the database. 8. Click OK. The imported data appears in the database.
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Lesson 1.1 Creating a Project and Importing Data
Figure 1.7 Data imported to mag.gdb
You can also drag and drop Geosoft XYZ files from Windows Explorer into an open database. Now, you will import geochemistry data from a CSV format file using another method. In this case, instead of creating a new database before importing the data, you will import the data and create the database all in one step. To import CSV format data and create a new database: 1. From the Database menu, select Import and then Ascii. The Import message window opens asking if you want to import data into the current database. 2. Click No. The Create New Database dialog appears. 3. For the New database name, enter geochem.gdb and click OK. The Import ASCII dialog opens in the foreground and the new geochem database opens in the background. Figure 1.8 Import ASCII dialog
4. For the File(s) to import, click the Browse button
.
5. From the Geochemistry folder, select geochemistry.csv and click Open.
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Module 1: Working with Databases 6. Click Create Template. The Data Import Wizard - Step 1 of 3 dialog opens. Figure 1.9 Data Import Wizard - Step 1 of 3 dialog
7. Ensure the File Type is Delimited and click Next. The Data Import Wizard - Step 2 of 3 dialog opens. Figure 1.10 Data Import Wizard - Step 2 of 3 dialog
8. Ensure the Column delimiters is Microsoft Excel CSV and click Next. Data Import Wizard - Step 3 of 3 dialog opens.
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Lesson 1.1 Creating a Project and Importing Data
Figure 1.11 Data Import Wizard - Step 3 of 3 dialog
9. Click Finish. The Import ASCII dialog is again displayed. 10. Click OK. The new geochem.gdb opens in your project. To set new current X,Y,Z coordinate channels: 1. Make sure geochem.gdb is the current database. 2. From the Coordinates menu, select Set Current X,Y,Z Coordinates. The Set current x,y channels dialog opens. Figure 1.12 Set current x,y channels dialog
3. Select Current X (Easting) and Current Y (Northing) channels as Long and Lat. When applicable, you can also set the Current Z (Elevation) channel. 4. Click OK. Your database now has set X and Y channels which can be seen by the inverse x and y on the right side of the channel header cell.
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Module 1: Working with Databases
Figure 1.13 Set coordinate channels Oasis montaj
Examine the data imported into the geochem database. Notice that the Long and Lat channels are displayed as decimal degrees. You will change this to degrees, minutes, seconds by editing the display parameters for the channel. To edit the display of a channel: Examine the data listed in the Project Explorer. You have two databases associated with your project. The highlighted database is the selected or active database. 1. Make sure that geochem.gdb is the active database. If it is not, click on the database in either the Project Explorer or the Workspace to select it and make it active. 2. Right-click in the Long channel header cell and select Edit. The Edit Channel dialog opens.
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Lesson 1.1 Creating a Project and Importing Data
Figure 1.14 Edit Channel dialog
3. From the Format list in the Display section, select Geographic. 4. For Decimals, enter 2. 5. Click OK. 6. Repeat steps 2 to 5 for the Lat channel. The coordinates are now displayed as degrees, minutes, seconds.
Geosoft Databases The figure below outlines the main characteristics of a Geosoft Database. Figure 1.15 Geosoft Database characteristics
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Module 1: Working with Databases Unlike traditional spreadsheets, the spreadsheet windows provide a view of your database instead of the actual data in the database. You can customise the spreadsheet to display data to your specifications. It also lets you work with data in the spreadsheet without actually making changes to the data until you decide to save the database. After you save the database, your changes are permanent. Channel Header Cells are label cells used to identify the type of data contained in a spreadsheet column. The channel headers provide a visual indication of the current status of the displayed channel. A black triangle in the top left corner of the header cell indicates the channel is read-only and may not be modified. When you import data, all of your data is automatically displayed. You may want to hide certain channels from display in the spreadsheet window. In this lesson you will learn about the numerous tools available in Target that allow you to work more easily and effectively with data contained within a Geosoft database. First you will hide a channel from the spreadsheet view of a database and then return that channel to the view. To hide a channel from view in the database: 1. In the Project Explorer, double-click the mag.gdb database. This is now the current database. 2. Click the channel header cell of the Mag channel. The Mag channel is selected. 3. Right-click and select Hide Column. The channel is hidden from the spreadsheet view; however, the mag.gdb database still contains the data. You can also hide the selected channel by pressing the Spacebar. To view a hidden channel in the database: 1. Click the channel header cell of the empty channel. The empty channel is selected. 2. Right-click and select List. A box appears beneath the empty channel header cell listing the available channels that currently are not being viewed in the spreadsheet window. 3. Select Mag and click OK. The channel is now displayed in the spreadsheet. If you know the name of the data channel, you can position the cursor in an empty channel header cell, type the name of the channel and press Enter.
Channel Protection When you import data into your database, it is automatically stored as protected data as indicated by the black triangle in the upper-left corner of the channel header cell. When channels are protected, the data within cannot be modified.
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Lesson 1.1 Creating a Project and Importing Data
To remove channel protection: Right-click the Mag channel header cell and clear the check mark beside Protected. The black triangle disappears and the channel is no longer protected. You can also select Protect None and all channel protections will be removed. To protect a channel: Right-click the Mag channel header cell and select Protected. The black triangle appears in the channel header cell and the channel is protected. You can also select Protect All and all channels will be protected from editing.
Profile Window The Profile window shows a graphical representation of the data in your Geosoft Database. The profile appears in a window attached to the database. You can display up to five profile windows and up to a total of 128 profiles. The figure below outlines the main characteristics of the Profile window. Figure 1.16 Profile window
To display a profile: Right-click in the Mag channel column and select Show Profile. The Profile Window opens below the spreadsheet.
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Module 1: Working with Databases
Figure 1.17 Profile of Mag channel
Profile windows are dynamically linked to the database. When you select a value or range of values in either the database or profile window, they are also highlighted in the other window. To remove a profile: Right-click in the "Mag" channel header cell and select Remove Profile. The profile is no longer displayed.
Saving a Project When you save a project, all changes are saved to the data you have in your project, including maps, grids and databases. To save your project: From the File menu, select Project then Save. - ORClick the Save Project
button on the Project Explorer toolbar.
If you close your project without saving it, you will be prompted to save any modified documents.
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Lesson 1.1 Creating a Project and Importing Data
In this lesson you: Created a project Created a new database Imported data Saved the project
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Module 1: Working with Databases
Lesson 1.2 Defining the Coordinate System In this lesson you will: Define the coordinate system for a database Edit the display of a database channel Create new projected coordinates Set the current X, Y channels
Understanding Geosoft Coordinate Systems A coordinate system defines how geographic coordinates on the earth (e.g., a point on the surface of an elliptical Earth) are projected onto a flat map sheet. When dealing with coordinate systems, it is important to be aware that the geographic map location (X,Y) of any information is either in an implied or a known coordinate system. If you do not define the coordinate system for your data, Oasis montaj assumes that all locations (X, Y) are in an “unknown” coordinate system. You must define map projections if you want to: Annotate maps with longitude, latitude locations Convert the location of information (data or grids) from one coordinate system to another Display information on a map that is in a different coordinate system Define a warped coordinate system to fit data to a desired map coordinate system Working with coordinate systems in Oasis montaj requires that the map coordinate system information be attached to the data. Once you have attached a coordinate system to a set of coordinate channels, a Geographical Information (*.GI) file is attached to your data. Data from different coordinate systems can be displayed together on the map, as long as the coordinate systems are defined. Oasis montaj handles any reprojections that may be required to properly display data together. A map coordinate system can be assigned to a pair of channels in a database, to a grid, and to a data view in a map. In most cases, this involves defining the coordinate system of the "X" and "Y" channels in a database. This coordinate system will then be passed on to grids when data is gridded and map views will inherit this coordinate system when they are created. Coordinate systems for data channels, grids and views can be viewed and modified at any time, although the modification of map coordinate systems requires specific and accurate knowledge of the coordinate system information. When you define (or modify) a coordinate system, the coordinates of the data (database, grid or map view) remain unchanged. However, when you reproject data into another coordinate system the numerical representation of the coordinates will change.
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Lesson 1.2 Defining the Coordinate System
Assigning a Coordinate System The Coordinate System tool assigns a known coordinate system to a pair of coordinate channels in a Geosoft Database. In this lesson, you will assign a coordinate system to coordinate channels in the geochem.gdb. To select the georeference database channels: 1. Make sure geochem.gdb is the active database. 2. From the Coordinates menu, select Coordinate System. The Georeference database channels dialog opens. Figure 1.18 Georeference database channels dialog
You can also right-click in a column header cell and select Coordinate System. 3. For the X channel, select Long. 4. For the Y channel, select Lat. 5. For the Set as current X, Y? option, select Yes. This assigns the Long and Lat channels as the X and Y coordinate channels that will be used for creating maps. 6. Click Coordinate System. The Coordinate System dialog opens indicating the current coordinate system is unknown. Figure 1.19 Coordinate System dialog
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Module 1: Working with Databases
To assign the coordinate system: 1. For the Coordinate system, click Geographic (long,lat). You can also copy coordinate system information from a Database, Grid, Voxel, Geosoft Projection, Esri Projection, Esri Coordinate System, Warp, Polygon, or GM-SYS Model. For more information on the selected projection method or to create a custom projection, click the More button . 2. From the Datum list, select GDA94. The Local datum transform defaults to [GDA94] (1m) Australia - onshore. 3. Click OK. The coordinate system is applied to the long and lat channels. These channels are now the current X and Y channels as indicated by the blue x and y markers in the channel header cells. To ensure consistency between your databases and grids, you should set the coordinate system for your databases before creating grids or maps from them. You can set Oasis montaj to prompt you to assign a coordinate system whenever you import data into a new database. To set this prompt, from the Settings menu, select Global Settings then General, click Next. Select Yes, for the "Specify coordinate system on import" parameter.
Creating a New Projected Coordinate System The New Projected Coordinate System tool takes existing coordinates and reprojects those coordinates to create a new set of coordinates in a different coordinate system. This is a four-step process; you will identify a pair of existing coordinate channels, verify or set their coordinate system, identify the new pair of coordinate channels, and verify or set the coordinate system for the new coordinate channels. In this lesson, you will create additional coordinate channels in your geochem database, which will contain projected (metre) coordinates, rather than the existing geographic (long, lat) coordinates. To create coordinates in a different coordinate system: 1. From the Coordinates menu, select New Projected Coordinate System. The Enter existing coordinate channels dialog opens. The Long and Lat channels are already selected as the current X and Y channels as these were assigned in an earlier step.
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Lesson 1.2 Defining the Coordinate System
Figure 1.20 Enter existing coordinate channels dialog
2. Click Next. The Coordinate System dialog opens. Currently, the coordinate system is set to a Geographic system: GDA94 (1m) Australia . Figure 1.21 Coordinate System dialog
3. Click OK. The Create new coordinate channels dialog opens. Figure 1.22 Create new coordinate channels dialog
4. For New X/Longitude channel, enter X_MGA50. 5. For New Y/Latitude channel, enter Y_MGA50. These are the new coordinate channels that will be reprojected from the existing geographic (lat/long) coordinates to projected (metre) coordinates. 6. Click Next. The Coordinate System dialog opens. By default, it remembers the last coordinate system that was entered, in this case, Geographic. You will now enter the appropriate projected coordinate system for the new coordinate channels.
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Module 1: Working with Databases
Figure 1.23 Coordinate System dialog
7. For the Coordinate system, click Projected (x, y). The coordinate system defaults to the parameters you entered when you selected the Projected (x, y) coordinate system option for the mag database, which in this case, is correct. Always verify that the coordinate system is set correctly for the channels you are assigning it to. 8. In this case the projection method dropdown will update to the correct projection method Map Grid of Australia zone 50, because you earlier set this projection method for the mag.gdb. 9. Click OK. Two new coordinate channels are added to the database and the MGA50 projection is now assigned; however, the current X, Y channels are still set to Long and Lat.
Setting the Current X, Y Channels Current X, Y (and Z) channels are used to define which pairs of coordinates will be used for creating maps. Blue x and y markers in the channel header cells indicate which channels are the current X, Y (and Z) channels. When you change the current coordinate channels, these markers also change. Now that you have reprojected your coordinates from longitude and latitude to MGA, you will select the X_MGA50 and Y_MGA50 channels as the current X and Y channels. To set the current X, Y channels: 1. From the Coordinates menu, select Set Current X, Y, Z Coordinates. The Set current X, Y channels dialog opens.
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Lesson 1.2 Defining the Coordinate System
Figure 1.24 Set current X, Y channels dialog
2. For Current X (Easting), select X_MGA50. 3. For Current Y (Northing), select Y_MGA50. 4. Click OK. The X_MGA50 and Y_MGA50 channels are now the current X and Y channels as indicated by the blue x and y markers in the channel header cells. Now would be a good time to save your project.
In this lesson you: Defined the database coordinate system Edited the display of a database channel Created new projected coordinates Set the current X, Y channels
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Module 1: Working with Databases
Lesson 1.3 Georeferencing Your Data In this lesson you will: Define a Warp Open a Map Edit a File
Georeferencing Georeferencing is the process of reprojecting data coordinates numerically. In Oasis montaj, georeferencing is a two-step process in which you first define a warp file (*.wrp) and then apply the warp file to your data or grid.
Defining a Warp There are three methods of defining a warp file. These are: Interactively: You use the mouse to select a point for warping and then click to identify the new location for that point. Semi-interactively: You use the mouse to define up to 4 control points for warping. For each point, the system shows the current coordinates and prompts you to enter new projection coordinates. Manually: You manually enter both the old and new positions in a dialog. The number of control points you define will determine the type of warping that is performed. This is described in the following table: Table 1.1 Types of translations
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No. of Points
Type of Translation
1
X, Y shift
2
X, Y shift, scale and rotation
Example
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Lesson 1.3 Georeferencing Your Data
No. of Points
Type of Translation
3
X, Y shift, scale (in X and Y) and rotation
4
Full quadrilateral warp (to warp one rectangular region into another)
>=2
Multipoint Warp performs an exact warp for all selected points.
Example
Use warping when you have data in an arbitrary coordinate system and want to locate the data in a real coordinate system. For example, you may have an image with only pixel coordinates and want to import the image into a map with projected coordinates. In this lesson, you will first georeference a database from local coordinates to Geocentric Datum of Australia (GDA) coordinates by defining a warp file manually. Later, you will georeference a geology map using the semi-interactive method. To manually define a warp: 1. Ensure that the mag.gdb is open and selected in your project. 2. From the Geophysics folder, open Mag Survey-LCL Grid info.txt in a text editor. These are the coordinates you will assign to the database. 3. From the Coordinates menu, select Georeferencing then Define a Warp. The Warp File Creation dialog opens. Figure 1.25 Warp File Creation dialog
4. For the Output Warp file name (*.wrp), enter local2gda. 5. For Warp Type, select 2-Point Scale & Rotate.
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Module 1: Working with Databases 6. For Definition Mode, select Manual. 7. Click OK. A Map projection window opens asking if you want to define the output coordinate projection. 8. Click Yes. The Coordinate System dialog opens. Figure 1.26 Coordinate System dialog
To assign the coordinate system: 1. The Coordinate System dialog should be displayed in your project. 2. For the Coordinate system select Projected (x,y). If a coordinate system has previously been defined in your project, Oasis montaj will default to the last chosen system. The destination Coordinate system for this exercise should be Projected, Map Grid of Australia Zone 50. If this is the case, please skip steps 3-4 below. 3. From the Projection method list, select Map Grid of Australia zone 50. For more information on the selected projection method or to create a custom projection, click the More button. 4. From the Datum list, select GDA94. The Local datum transform defaults to [GDA94] (1m) Australia - on shore. 5. Click OK. The Assign new coordinate 1 of 2 dialog opens. You will enter the coordinate information for the first point.
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Lesson 1.3 Georeferencing Your Data
Figure 1.27 Assign new coordinate 1 of 2 dialog
6. From the Mag Survey-LCL Grid info.txt file, cut and paste the Original X and Y coordinates (0.0, 0.0). 7. Cut and paste the New X and Y coordinates (714660.00, 6528300.00). 8. Click Next. The Assign new coordinate 2 of 2 dialog opens. You will enter the coordinate information for the second point. 9. Cut and paste the Original X and Y coordinates (2900.00, 4300.00). 10. Cut and paste the New X and Y coordinates (717560.00, 6532600.00). 11. Click Finish. The local2gda.wrp file is created and can be opened and viewed in a text editor. Next, you will apply the warp file to the database. To apply the warp to the database: 1. Ensure that the mag.gdb is open and selected in your project. 2. From the Coordinate menu, select Georeferencing then Warp Data. The New coordinate channels dialog opens. Figure 1.28 New Coordinate channels dialog
3. For the Current X/longitude channel, select X_local from the dropdown list. 4. For the Y/latitude channel, select Y_local from the dropdown list. 5. For the Warp definition file (.wrp), click the Browse button. 6. From the Geosoft Training Data folder, select local2gda.wrp and click Open. 7. For the Output X/longitude channel, enter X_MGA50. 8. For the Y/latitude channel, enter Y_MGA50 and click OK. The new coordinate channels are added to the database.
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Module 1: Working with Databases Now that you have georeferenced your database to MGA coordinates, you will select the X_MGA50 and Y_MGA50 channels as the current X and Y channels. To set the current X, Y channels: 1. From the Coordinates menu, select Set Current X, Y, Z Coordinates. The Set current X, Y channels dialog opens. Figure 1.29 Set current X, Y channels dialog
2. For Current X (Easting), select X_MGA50. 3. For Current Y (Northing), select Y_MGA50. 4. Click OK. The X_MGA50 and Y_MGA50 channels are now the current X and Y channels as indicated by the blue x and y markers in the channel header cells. Figure 1.30 New coordinate channels
Now would be a good time to save your project. Now that you have georeferenced your database, you will open a map to define a warp interactively.
Opening a Map In this exercise you are going to define a warp interactively by digitizing the control points on a map. Creating Geosoft maps will be covered in detail in a later module, for this exercise we are going to open a map that was created earlier.
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Lesson 1.3 Georeferencing Your Data
To open a map: 1. On the Map menu, select Open Map. The Open Map dialog appears. 2. From the Geosoft Training Data folder, select the Mt Palmer.map and click Open. The Mt Palmer.map is opened in your current workspace and should look similar to the map below. . Figure 1.31 Mt Palmer example map
Next, you will warp an unregistered scanned geology map to latitude and longitude coordinates using the semi-interactive method. You will begin by displaying the image that the geology map is stored as. To display the map to be warped: 1. From the Grid and Image menu, select Display on Map then Image (bmp,tiff,etc.). The Place an image on a map dialog opens. Figure 1.32 Place an image on a map dialog
2. For Image, click the Browse button and locate the Geology folder.
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Module 1: Working with Databases 3. Change the Files of type list to Tiff Image and select WA_geology-LL.tif and click Open. 4. For Location, select default registration. 5. Click New Map. The scanned geology map opens in a display window. Figure 1.33 Geology map
Now that you have opened the image that will be warped, you will define the warp file. To set up to define a warp file semi-automatically: 1. From the Geology folder, open the open WA_geology-LL info.txt in a text editor. These are the coordinates you will assign to the unreferenced map. Notice the coordinates of the four control points are in latitude and longitude. 2. From the Coordinates menu, select Georeferencing then Define a Warp. The Warp File Creation dialog opens. 3. For the Output Warp file name, enter mapwarp. 4. For the Warp Type, select 4-Point Quadrilateral Warp. 5. For the Definition Mode, select Semi-interactive. This method enables you to click on the map and enter coordinate information. 6. Click OK. The Map projection window opens asking if you want to define the output coordinate projection. 7. Click Yes. The Coordinate System dialog opens. To define the coordinate system: 1. For the Coordinate system, select Geographic (long, lat).
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Lesson 1.3 Georeferencing Your Data 2. From the Datum list, select GDA94. The Local datum transform defaults to [GDA94] (1m) Australia - onshore. 3. Click OK. A message window opens informing you to select point locations to use as control points for warping. These locations should be: as close to the edge of the map as possible; located at intersecting lines or meridians; and, collected in either a clockwise or counter-clockwise order. To collect warp control points: 1. Click OK on the Define Warp control points dialog. 2. Click the lower-left corner of the image. The Assign new coordinate 1 of 4 dialog opens showing the current pixel coordinates and the new coordinates. 3. Using the coordinates in the table below, enter the New X and Y coordinates for each of the corresponding corner control points: Approx. Pixel and Line Coordinates
Lat/ Long Coordinates
Lower Left
0, 0
-31.41935057
119.1333894
Upper Left
0, 455
-31.26137440
119.1333894
Upper Right
800, 455
-31.26137440
119.4098476
Lower Right
800, 0
-31.41935057
119.4098476
Corner
Right-click to access tools to zoom, pan and redraw the image display. 4. When you have entered all four New X and Y coordinates, click the Finish button. The new mapwarp.wrp file will be created.
Editing a File A Geosoft Warp file (*.wrp) is an ASCII file that can be edited in any text editor, such as Notepad. To open the warp file in a text editor: 1. From the Edit menu, select Edit a File. The Edit file dialog opens. 2. Click the Browse button and open mapwarp.wrp. 3. Click OK. The warp file opens in a Notepad window.
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Module 1: Working with Databases
When interactively selecting the control points, it is difficult to select the very edges of the image. Hence you will see in the warp file that the pixel coordinates, which should be one of 0, 455 or 800 (in accordance with the edges of the image) are not exact. If you wish you can use the text editor to adjust the pixel coordinates accordingly. Now that you have created the warp file and viewed it in a text editor, you will apply it to the raw, unregistered image. To apply the warp to the image: 1. From the Coordinates menu, select Georeferencing then Warp a Grid. The Warp a grid dialog opens. Figure 1.34 Warp a grid dialog
2. For the Input grid click the Browse button. 3. Locate the WA_geology-LL.tif file from the Geology folder, remembering to change the Files of Type to Geo Tiff (*.tif). This is the image that will be warped based on the warp file you just defined. 4. For the Warp definition file, click Browse and select mapwarp.wrp. 5. For the Output warped grid, click the Browse button. 6. For the File name, enter WA_geology-LL_warped.tif and for the Save as type, select GeoTIFF COLOR. 7. Click Save. 8. On the Warp a grid dialog click Default. A default cell size is calculated to give approximately the same number of grid cells in the new grid as are in the old. By clicking Default, this value is determined and may be modified as needed.
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Lesson 1.3 Georeferencing Your Data 9. Click Next. The New warped grid dialog opens. Figure 1.35 New warped grid dialog
10. Review the information and click Finish. Applying a grid warp is very memory intensive and can be timeconsuming for large or high-resolution images. Adding more RAM to your computer may decrease processing time. Now that you have applied the warp to the geology map, you will display it and examine the coordinates. To display the warped image: 1. In the Data section of the Project Explorer, expand the Grids category. 2. Right-click Grids and select Open Grids. The Add New Grid window opens. 3. Change the Files of type list to Tiff Image, select WA_geology-LL_warped.tif and click Open. The new warped map opens in a display window. As you move your cursor around, note the latitude and longitude coordinates displayed on the status bar. Figure 1.36 Geology map with latitude and longitude coordinates
Now would be a good time to save your project. To display the warped image on your map: From the Project Explorer, drag and drop WA_geology-LL_warped.tif into your Mt Palmer map.
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Module 1: Working with Databases The new warped map is reprojected on-the-fly to match the coordinates of the mag data. As you move your cursor around, note the projection and coordinate information displayed on the status bar matches the projection of the mag data. Figure 1.37 Geology map displayed with MGA coordinates on the Mt Palmer map
Now would be a good time to save your project.
In this lesson you: Defined a Warp Opened a Map Edited a File
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Lesson 1.4 Working with Database Tools
Lesson 1.4 Working with Database Tools In this lesson you will: Split a line Examine channel statistics Edit a channel Create a new channel Compute mathematical expressions Work with channel math expression builder Use profile options Create a distance channel Save the database
Database Tools There are a variety of tools within Oasis montaj that you can use to manipulate your databases. This lesson will introduce you to some of the more commonly used database tools that are available.
Splitting a Line Geophysical data is often collected in lines. When this data is stored in an ASCII format, the data is rarely stored in separate lines, rather the different lines are denoted by a line number field. The ‘Split a line based on a line channel’ tool is used to break up this type of data into separate lines. If you inspect your "mag" database, you will see that the data is currently in one line, but there is a "Line" channel that contains a series of line numbers. You are going to use that channel to split the database into separate lines. To split lines: 1. Select the mag.gdb database. 2. Right-click in the Mag channel header cell and select Show Profile. The profile is displayed below the database window. 3. From the Database Tools menu, select Line Tools then Split on Line Channel. The Split a line based on a line channel dialog opens. Figure 1.38 Split a line based on a line channel dialog
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Module 1: Working with Databases 4. For the Line to split, ensure D0 is selected. 5. For the Line reference channel, select Line. 6. For the Reset fiducial start values to zero, check the box. 7. Click OK. The database updates and displays the profile for line L11:0. Figure 1.39 Profile of Mag channel after splitting lines
Channel Statistics Statistical information about your data can be very useful for general quality control and to ensure the values are in range with what you would expect. You will now calculate statistics for the Mag channel in the mag.gdb database. Table 1.2 Methods for calculating statistics
To:
Do this:
Calculate statistics for selected cells
Click and drag to select the desired cells, right-click and select Statistics.
Calculate statistics for a selected line of the database
Click the channel header cell two times, right-click and select Statistics.
Calculate channel statistics for all of the selected lines in the database
Click the channel header cell three times, right-click and select Statistics.
The Stat Report dialog opens.
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Lesson 1.4 Working with Database Tools
Figure 1.40 Stat Report dialog
You can access the same statistic report by selecting Mark Statistics from the Database Tools then Report menu. To generate a line/channel report: 1. From the Database Tools menu, select Report then Line/Channel Report. The Channel data statistics dialog opens. Figure 1.41 Channel data statistics dialog
2. From the Channel(s) to calculate statistics list, select Mag. The report will be saved to stats.txt. 3. Click OK. If this is your first time opening a text file in Oasis montaj, the Select a default text editor dialog opens. Figure 1.42 Select a default text editor dialog
4. Click the Browse button to select a default text editor or click OK to select the default. The stats.txt report opens in a text editor.
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Module 1: Working with Databases
Figure 1.43 Line/Channel Report (data truncated for brevity)
To display the profile of a different line: 1. Click the line header cell in the top left corner of the spreadsheet. The line currently displayed is L11:0. 2. Right-click and select List. A list of all the line numbers in the current database is displayed. Each line number is like a worksheet in the spreadsheet window. When you view a new line number, a new worksheet opens in the spreadsheet window with the corresponding line number information. 3. Select L61:0. The spreadsheet window and the profile view update based on line L61:0.
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Lesson 1.4 Working with Database Tools
Figure 1.44 Profile of line 61
When the line header cell is selected, you can use the Page Up and Page Down keys to scroll through the lines. On line L61:0, notice that there are two drop-outs in the data. These are likely errors or noise that you would want to edit or remove from your data. You will now create a copy of the original Mag channel so that you can deal with these errors without modifying the original data. To copy a channel: 1. From the Database Tools menu, select Channel Tools then Copy Channel. The Copy a channel dialog opens. Figure 1.45 Copy a channel dialog
2. For Copy FROM, select Mag. 3. For TO, type Mag_edited. 4. Click OK.
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Module 1: Working with Databases The Mag channel is copied to the new Mag_edited channel.
Editing a Channel in the Database Now that you have made a copy of the Mag channel, you will edit the data by deleting the two drop-outs found on line L61:0 of the mag.gdb database. You can select data within either the speadsheet view or the profile window in order to edit it. To edit a channel using the Profile window: 1. Ensure you are viewing line L61:0. 2. Right-click in the Mag_edited channel and select Show Profile. 3. In the Profile window, click on the first spike. A square appears at this point in the profile and the corresponding data value of 0.00 is selected in the database. Figure 1.46 Spike selected in Profile window
4. Press the Delete key or the Spacebar on your keyboard. The dummy value (*) replaces the original value of 0.00. 5. Repeat steps 3 and 4 to delete the second spike. Now that you have removed the spikes, you will interpolate the data to fill in the gaps created when you removed the spikes. Interpolation uses the data located adjacent to the removed data points to populate those points with a new data value. To interpolate the data: 1. From the Database Tools menu, select Channel Tools then Interpolate. The Interpolate Dummies dialog opens.
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Lesson 1.4 Working with Database Tools
Figure 1.47 Interpolate Dummies dialog
2. For the Channel to interpolate, select Mag_edited. 3. For the Output interpolated channel, select Mag_edited. The interpolated values will be written back to the input channel. 4. For the Interpolation method, select Minimum Curvature and click OK. The gaps in the data created by editing the spikes are interpolated. You may want to zoom into your profile display to see more detail in the edited profile. To zoom in the Profile window: 1. In the Profile window, right-click and select Zoom. 2. Define the size of the zoom area by drawing a box. 3. Click to identify the location of the zoom box. Figure 1.48 Zoomed view of edited profile
To zoom out in the Profile window: Right-click in the Profile window and select Rescale All.
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Module 1: Working with Databases
Creating a New Channel You can create new channels in your database to store the results of filters, mathematical expressions, or other processing operations. You should create a new channel for storing any changes you make to the original imported data. In this lesson, you will create a new channel to store the results of a mathematical expression. To create a new channel: 1. Select the geochem.gdb database. This is now the current database. 2. In the empty channel header cell to the right of the Y_MGA50 channel, type Pb_ Zn and press ENTER. The Create Channel dialog opens. Figure 1.49 Create Channel dialog
3. For Decimals, enter 4. 4. Click OK. The new channel is added and is filled with dummy, or null, values, as indicated by a single asterisk. A single asterisk (*) indicates a dummy or null value. A double asterisk (**) indicates the channel is not wide enough to display the values and should be resized.
Computing a Mathematical Expression Now that you have added a new empty channel, you will use the advanced status bar feature in the spreadsheet window to apply a mathematical expression to the data selected in your spreadsheet window. You can select a portion of a channel, an entire channel on a single line, or the same channel on all lines in your database. In this example, the contents of the new channel will be the ratio of lead to zinc.
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Lesson 1.4 Working with Database Tools
To compute a new channel of data: 1. Click the Pb_Zn channel header cell three times. This ensures that all the data in that channel is selected, even if the data is stored in multiple lines or groups. 2. Press the equal sign (=) key on your keyboard. The status bar at the bottom of the spreadsheet window changes to "Formula=". 3. In the Formula= box, type Pb/Zn and press ENTER. The values are calculated and output to the Pb_Zn channel. Figure 1.50 geochem.gdb with new channel
Channel Math Expression Builder Now you will use the Channel Math Expression Builder to compute new data. With the Channel Math Expression Builder you can create, save, load and execute math expressions on data that is stored in database channels. In this example, you will use a true/false expression to create a new channel named High_Cu that contains only data where Cu is higher than 70ppm; if the value is less than that, the channel will contain a dummy value. To use the Channel Math Expression Builder: 1. From the Database Tools menu, select Channel Math. The Channel Math Expression Builder dialog opens.
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Module 1: Working with Databases
Figure 1.51 Channel Math Expression Builder dialog
2. From the list of Common tasks, select True/False statement. The Expression box at the top updates with an example mathematical expression: C0 = (C1>5000) ? (C1) : (DUMMY); where C0 is the name of a new channel, and C1 is the name of an existing channel. 3. In the Expression box, change the value of 5000 to 70. In this example, all Cu values greater than 70 ppm will be output to the new channel. You will now assign the channels. 4. In the Assign channels box, click in the box beside the C0 channel and enter High_Cu. A new channel called High_Cu will be created when this expression is computed. 5. From the list beside the C1 channel, select Cu. The expression that will be computed [C0 = (C1>70) ? (C1) : (DUMMY);] can be read as follows: the new High_Cu channel (C0) will contain values of Cu (C1) that are greater than 70 ppm; otherwise, a dummy value will be output. You can save your math expression for use at a later time or in another project. Enter a name in the Expression file box and click Save. It will be saved to an .exp file in your project folder. 6. Click OK. A new channel named High_Cu containing the results of this expression is added to your geochem database. Figure 1.52 geochem.gdb with two new channels
Next, you will use tools in the profile window to display and compare the values in the High_Cu and Cu channels to visually identify high Cu values.
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Lesson 1.4 Working with Database Tools
To compare profiles: 1. Right-click in the High_Cu channel and select Show Symbol Profile. The High_Cu values are displayed with a default symbol style. 2. Right-click in the Cu channel and select Show Profile. Figure 1.53 High_Cu and Cu profiles
Notice how the data is not displayed using the full profile window, because a subset of the data within the database do not contain Cu values (i.e. those samples were not assayed for Cu. You will now adjust the range of the X-Axis in order to ultilise the entire profile window to better view the data. To adjust the section of profile visible in the Profile window: 1. In the lower part of the profile window, place your cursor over the right side of the white box representing the visible section of the profile line on the X axis. The cursor changes to a double-headed arrow. 2. The values in the X-Axis represent the fiducial value. Drag the right edge of this box to the left until the upper fiducial value decreases to approximately 880. The data now fills the entire profile window.
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Module 1: Working with Databases
Figure 1.54 High_Cu and Cu profiles with adjusted X axis range
By displaying the two profiles in the same profile window, the high Cu values can be easily identified. However, note that the profiles are currently plotted to different vertical scales that are derived from the respective data ranges of their channels; the range for Cu is (8 to 121) and High_Cu is (70 to 121). You will now adjust the vertical (Y) scale of the profile window so that both profiles are plotted to the same scale.
Profile Options The Y-Axis Options dialog enables you to set scale options for the Y axis in the profile window. The following table summarizes the options available in the Y-Axis Options dialog: Table 1.3 Profile Options
Select this:
To do this:
Changing Lines Scale to fit for each line
Adjusts the scale in the profile box to fit each line that is displayed.
Same axis scale for all lines
The axis minimum and maximum scale values are kept the same when changing between lines.
Same dynamic range, centred for each line
Fixes the vertical scaling factor and displays the line in the centre of the window.
Profile Scaling
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Lesson 1.4 Working with Database Tools Select this:
To do this:
Scale each profile separately
All profiles are scaled separately.
Same axis scale for all profiles
Uses the same axis scale for all profiles that are displayed.
Same dynamic range, centred for each profile
All profiles are plotted using the same vertical scaling factor, but are centred individually on their own mid-data value.
Axis Direction Positive up
The Y-axis is positive in the upward direction, as in the Cartesian system, the positive Z direction is up, as are elevations.
Positive down
The Y-axis is positive in the downward direction, as when depth values increase downwards. If the data along the Y-axis increases downward, you can view the data as it naturally occurs, without altering the data.
You will now adjust the scaling options to more effectively compare the two profiles by adjusting the Y axis scale. To display the two profiles at the same scale: 1. In the Profile window, right-click and select Y Axis Options. The Y-Axis Options dialog opens. Figure 1.55 Y-Axis Options dialog
2. Select Same axis scale for all profiles and click OK. The profile display updates based on the same Y axis scale.
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Module 1: Working with Databases
Figure 1.56 Profiles with same Y axis scale
Creating a Distance Channel Currently the X-Axis of the profile window is scaled based on the fiducial value, which is essentially a "record" or sample number that is created when importing data into a Geosoft database. In practice it would be better to use a physical quantity such as distance to scale the profile window by. The Create a distance channel tool calculates a distance channel from provided X and Y channels. The first point on each line is at distance 0 and subsequent points are calculated from the cumulative distance down the line. A distance channel could be used to calculate the distance between points or stations. To create a distance channel: 1. From the Database Tools menu, select Channel Tools then Make Distance Channel. The Create a distance channel dialog opens. By default, the X_MGA50 and Y_ MGA50 channels are listed as the X and Y channels as these were selected as the current X and Y channels when defining the coordinate system for the database.
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Lesson 1.4 Working with Database Tools
Figure 1.57 Create a distance channel dialog
If you specify a Z channel, the distance channel will be calculated using all three axes. 2. Click OK. The distance channel is created and displayed in your spreadsheet window. Figure 1.58 Distance channel
You will now select the distance channel to use as the X-axis in the Profile window instead of the fiducial channel. To change the X-axis channel: 1. In the Profile window, right-click and select X Axis Options. The All-Panel Options dialog opens.
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Figure 1.59 All-Panel Options dialog
2. From the Select the Channel to use as X-Axis list, select Dist and click OK. The distance channel is now plotted on the X-axis. Figure 1.60 Distance channel plotted on X-axis
You cannot select a channel for the X-axis that is currently displayed as a profile.
Saving a Database Changing how data appears in the spreadsheet (i.e., showing or hiding channels) does not alter the data in your database; however, editing (i.e., adding or deleting channels or altering data values) does change your underlying database. You should save changes to your database whenever you perform a major editing or processing step. If you process your data and the results are not as you expected, you can restore your database to its previously saved state.
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Lesson 1.4 Working with Database Tools
To save changes to your database: 1. Select the geochem.gdb database. 2. From the Database menu, select Save Database Changes. You can also click the Save Changes icon window.
on the Database toolbar at the top of the database
The Save Changes message window opens asking if you want to save all changes to the current database. 3. Click Yes. Your database changes are now saved. 4. Select the mag.gdb database and repeat steps 2 and 3. To undo changes, select Discard Database Changes from the Database menu. This will restore your database to its last saved state.
In this lesson you: Split a line Examined channel and line statistics Copied and edited a channel Created a new channel Computed mathematical expressions Worked with the channel math expression builder Displayed multiple profiles and adjusted the profile options Created a distance channel Saved the database changes
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Module 1: Working with Databases
Lesson 1.5 Working with Array Data In this lesson you will: Import array data Add depth information to array data Visualize array data
Array Data Array data is data where multiple measurements are recorded at a given location. Examples of this data include seismic, induced polarization and some forms of electromagnetic data. In an array database, the multiple measurements are contained within a single data cell and are displayed in that cell using a mini-profile. Oasis montaj provides the ability to import, manipulate and visualize array channel information as well as array channel profile tools, including an Array Viewer to view your data. In this exercise, you will import conductivity data into an array database. The data in this case is modelled conductivity values derived from an IP/resistivity survey.
Import ASCII The Import ASCII enables you to easily import data from any ASCII spreadsheet or data file. The Data Import Wizard supports both Delimited and Fixed Field ASCII files. The Data Import Wizard also imports Microsoft Excel Comma Separated Value (CSV), Comma Delimited, White Space Delimited and Tab Delimited data files. To import an ASCII file into an array database: 1. From the Database menu, select Import and then Ascii. The Import ASCII dialog appears asking if you wish to import data into the current database, select No. The Create New Database dialog appears. 2. For the New database name, enter Mt Palmer Conductivity and click OK The Import ASCII dialog opens. Figure 1.61 Import ASCII dialog
3. For File to import the last file imported will be displayed by default. Click the Browse button, and from the Geosoft Training Data/Geophysics folder, select Mt Palmer Conductivity.txt.
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Lesson 1.5 Working with Array Data 4. Click Create Template. The Data Import Wizard - Step 1 of 3 dialog opens. Figure 1.62 Data Import Wizard - Step 1 of 3 dialog
5. Click Next. The Data Import Wizard - Step 2 of 3 dialog opens. Figure 1.63 Data Import Wizard - Step 2 of 3 dialog
6. Select Comma Delimited from the Column delimiters options. 7. Click Next. The Data Import Wizard - Step 3 of 3 dialog opens.
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Module 1: Working with Databases
Figure 1.64 Data Import Wizard - Step 3 of 3 dialog
It is always good practice to review your data to ensure that the wizard has selected the correct columns. 8. Click on each of the channels in the preview pane. 9. For each channel you can select an appropriate Channel Type. 10. For the "Line" channel select Line as the channel type. 11. For the "MtP_East", "MtP_Nth" and "Elevation" channels, select Data as the channel type. 12. For the "MtPalmer_Conductivity[0] channel, select Array as the channel type and enter 19 for the Size. 13. In the Channel Name field, enter Mt_Palmer_Conductivity. 14. In the Label field, enter Mt Palmer Conductivity. 15. Click Finish. The Import ASCII dialog is again displayed. 16. Click OK. The selected array channel is imported and displayed in the database.
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Lesson 1.5 Working with Array Data
Figure 1.65 Array Channel (Mt_Palmer_Conductivity) Imported into Geosoft database
To assign the coordinate system 1. Make sure Mt Palmer Conductivity.gdb is the current database. 2. From the Coordinates menu, select Coordinate System. The Georeference database channels dialog opens. 3. For the X channel, select MtP_East. 4. For the Y channel, select MtP_Nth. 5. For the Set as current X, Y? option, select Yes. This assigns the MtP_East and MtP_Nth channels as the X and Y coordinate channels that will be used for creating maps. 6. Click Coordinate System. The Coordinate System dialog opens indicating the current coordinate system is unknown. 7. For the Coordinate system, click Projected (x,y). The coordinate system defaults to the parameters you entered when you selected the Projected (x, y) coordinate system option for the mag database (Datum should be set to GDA94 and the Projection Method to Map Grid of Australia Zone 50), which in this case, is correct . Always verify that the coordinate system is set correctly for the channels you are assigning it to. 8. Click OK. The MGA50 projection is now assigned and the current X, Y channels are set to MtP_East and MTP_Nth.
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Module 1: Working with Databases
Adding Depth Information to the Array Array data is usually accompanied by some incremental 'base' property, which defines how multiple measurements at a single location are differentiated. Depending on the type of geophysical data, this array increment may be time, frequency, distance, depth or velocity. In order to process and visualize the data,this "base" information must accompany the array data. There are two ways of incorporating base information with array data. One is to import the base data as a separate array channel in the same database as the data array; The alternative is to 'attach' the base information to the data array channel. The Array Base Property dialog enables you to populate or edit the increment base property for a given array channel.
To add depth information to an array: 1. Select the Mt Palmer Conductivity database. 2. Right-click on the header cell of the Mt_Palmer_Conductivity channel. From the list of options select Array Base Properties. The Array Base Properties dialog appears. Figure 1.66 Array Base Properties dialog
3. From the Base dropdown menu, select Depths. 4. In the Initial Value, enter a value of 0. For the Increment field, enter a value of 0 to activate the fields, in which to enter the variable increments. In this case the depth increment increases with depth, therefore you have to enter the increment depths individually.
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Lesson 1.5 Working with Array Data 5. Enter the following index and depth values in the available fields: Index
Depths (m)
Index
Depths (m)
0
0
10
26.25
1
1.5
11
30.25
2
3.25
12
34.5
3
5.25
13
39
4
7.5
14
43.75
5
10
15
48.75
6
12.75
16
54
7
15.75
17
59.5
8
19
18
65.25
9
22.5
6. Click OK to finish.
Visualizing Array Data There are several means by which you can visualize array data in a Geosoft database. These are listed below: Profile Window - Plot your array in the profile window. You have the ability to choose a colour ramp for the profile plot. Plot Profile Figure - Plot your profile window as a separate "map" in your project workspace. Section Plot - Plot your array data as colours in each array cell. You have the ability to plot a section, profile, or both in each cell. Array Viewer - View each array of data in a separate viewer. The viewer enables you to customize the scale and other display parameters. It also enables you to create a separate plot of the array in your project workspace During this exercise you will investigate the features described above to change the appearance of your array database. To Visualize Array Data 1. In the Mt Palmer Conductivity database, select the Mt_Palmer_ Conductivity channel. 2. Right-click and select Array Prof/Sect Options. The Set cell profile/section options for an array channel dialog appears.
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Module 1: Working with Databases
Figure 1.67 Set cell profile/section options for an array dialog
3. Using the Cell Profile/Section options dropdown, select Profile and Section. 4. Click OK to finish. Your array channel is now coloured according to the data values in each cell. 5. Right-click the array channel header cell and select Array Section Colours. Figure 1.68 Set section colours for an array dialog
6. In the Colour table, click on the colour ramp. The Select Colour Ramp dialog appears. 7. From the Category dropdown list, select Geophysics and from the Files of Type dropdown lists, select All Types. 8. From the list of available colour ramps, select rainbow1.lut, click OK. 9. Click OK again to finish. The array channel section colours update accordingly. 10. Right-click the array channel header cell and select Array Profile Colours. The Set profile colours for an array channel dialog appears. Figure 1.69 Set profile colours for an array channel dialog
11. Repeat the procedure described in steps 6-8 to select the rainbow1.lut colour ramp. 12. Right-click the array channel header cell and select Edit. The Edit Channel dialog appears. 13. Set the Decimals to 2 and click OK. 14. Rick-click the array channel header cell and select Show Profile. The profile window now displays the array data in the specified colours.
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Lesson 1.5 Working with Array Data 15. Ensure you are looking at Line 1 of the Mt Palmer Conductivity database. In the profile window, right-click and select Plot Profile Figure. The Create a profile figure dialog appears. 16. In the Title field , enter Line 1 - Conductivity and click OK to finish. The profile plot is saved and displayed as a map in the project workspace. Figure 1.70 Mt Palmer Conductivity map
17. In the Mt Palmer Conductivity database, select the cell within the Mt_ Palmer_Conductivity array channel that corresponds to fiducial 25.0. 18. Right-click in that cell and select Array Viewer. The array channel profile viewer appears. Figure 1.71 Array Channel Profile Viewer
19. In the Base field, enter a value of 0. 20. Click on the Plot button. 21. In the Title field of the array profile dialog, enter "Line 1, Station 25 Conductivity". 22. In the X Axis Annotation field, enter "N Level" 23. In the Y Axis Annotation field, enter "Conductivity (mS/m)" 24. Click Plot. The individual array plot is saved and displayed as a map in the project workspace. 25. Click OK on the Array Channel Profile Viewer dialog.
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Figure 1.72 Line 1, Station 25 Conductivity Map
Your database should now look similar to the one shown in Figure 1.7 below. Figure 1.73 Mt Palmer Database
In this lesson you: Imported ASCII array data into a database Added depth information to the array Explored the array data visualization options Produced a profile plot of array data for a complete database line Produced a profile plot of an individual array cell
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Lesson 1.6 Filtering Databases and Grids
Lesson 1.6 Filtering Databases and Grids In this lesson you will: Apply a non-linear filter Apply a convolution filter Apply a filter to a grid Subtract grids
Filters Mathematical operators that modify a dataset in some way are known as Filters. Filters are a very important part of a geophysicists toolbox. The potential application of filters to geophysical data is unlimited and almost a discipline to itself, however they are generally used in two ways: To improve the signal to noise ratio of the data by identifying and removing noise To condition or enhance certain features in the data Oasis montaj provides numerous filters that can be applied in multiple dimensions. 1D filters are applied to a channel of data in a database, whereas 2D filters are applied to grid data and are commonly used in image processing applications. 3D filters can be applied to Voxels. Filters can also be applied in either the space domain, or the frequency domain via a Fast Fourier Transform (FFT). In this lesson, you will focus on space domain filters. To begin this lesson, you will display a profile of your original mag data. To display the original mag data on line 61: 1. Ensure your mag.gdb is open and selected in your workspace. 2. Right-click the header cell of the Mag_edited channel and select Remove Profile. The database and profile window update to show the original mag data on line 61:0. 3. Right-click the header cell of the Mag_edited channel again, and this time select Hide Column. The Mag_edited column is hidden from view. The column can be displayed at any time by right-clicking an empty header cell and selecting, List. Select the channel(s) to be displayed, from the list provided.
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Figure 1.74 Profile of line 61:0
When the line header cell is selected, you can use the Page Up and Page Down keys to scroll through the lines. On line L61:0, notice the two drop-outs that you removed and interpolated in Lesson 1.1. This time you will remove the drop-outs by applying a non-linear space domain filter.
Non-Linear Spatial Domain Filter The non-linear filter is a low-pass filter that can be used to locate and remove very short wavelength, high amplitude features from data. Data that is not defined as noise by the filter is not modified. This is particularly effective way to remove spikes from the data, but it can also be effective for removing short wavelength anomalies that are typically caused by man-made features, such as railway lines, buildings and power lines. To apply the non-linear filter: 1. From the Database Tools menu, select Filters, then Non Linear Filter. The Non-linear Filter dialog opens. Figure 1.75 Non-linear Filter dialog
2. For the Channel to filter, select Mag. 3. For the Output channel, enter NL_Mag.
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Lesson 1.6 Filtering Databases and Grids 4. For Filter Width, enter 3. This is the maximum width of the noise measured in data points. Features that are wider than this width will not be altered by the filter. 5. For Filter Tolerance, enter 500. Only noise of greater amplitude than this tolerance value will be altered. 6. Click OK. Now you will compare the filtered and unfiltered channel profiles to determine if the filter has removed the spikes. To view the profile of the filtered channel: Right-click in the NL_Mag channel header and select Show Profile. Figure 1.76 Comparison of Mag and NL_Mag profiles
Observe how the filter has removed the spikes and replaced them with values that are almost identical to the manual spike removal and interpolation done in an earlier lesson.
Convolution Filter The convolution filter applies a space-domain averaging filter to a channel. Depending on the coefficients used, the convolution filter can be used to exaggerate or smooth your data. To apply the convolution filter: 1. From the Database Tools menu, select Filters, then Convolution Filter. The Convolution Filter dialog opens.
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Figure 1.77 Convolution Filter dialog
2. For the Channel to filter, select Mag. 3. For the Output channel, enter Conv_Mag. 4. For the Filter File, click Browse and select laplace.flt. The Laplacian filter is a common space domain filter used to enhance high gradients. As such it is often used for source edge interpretation. 5. Click OK. The Laplacian convolution filter is applied and displayed in your new Conv_Mag channel.
Filtering Grids Filters are commonly used to smooth a grid before contouring in order to improve the appearance of the contours. In this application, 1 to 3 passes are usually sufficient. Another useful application is to produce a curvature grid. To do this, the Hanning filter is passed once over a grid and the result is subtracted from the original grid using the Grid Math Expression Builder. This residual is proportional to the curvature in the original grid, with zero values indicating inflection points. The curvature grid may be subsequently filtered to smooth noise. In this lesson, you will apply the convolution filter to remove the high frequency signal. Then, you will subtract this smoothed grid from the original mag grid to create a residual grid. To apply a filter to a grid: 1. From the Grid and Image menu, select Filters then 3x3 Convolution. The Grid Filters dialog opens. Figure 1.78 Grid Filters dialog
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Lesson 1.6 Filtering Databases and Grids 2. From the Input Grid File, click Browse, navigate to the Geophysics folder and select Mag_MC.grd. 3. For the New resultant Grid, enter mag_smoothed. 4. From the OPTION 1 - Select a Predefined Filter list, select Hanning. 5. Click OK. The new smoothed mag grid opens in a display window. Figure 1.79 mag_smoothed grid
Grid Math With the Grid Math Expression Builder, you can create, save, load and execute math expressions for your grid data. In this lesson you will create a residual grid by subtracting the smoothed grid from the original mag grid. To subtract grids: 1. From the Grid and Image menu, select Grid Math. The Grid Math Expression Builder dialog opens.
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Figure 1.80 Grid Math Expression Builder dialog
2. In the Expression box, enter G0 = G1 – G2. You can also select "Subtract 2 grids", from the Common Task dropdown list, instead of typing it manually. 3. In the Assign grids box, click in the list beside the G0 channel and type residual. A new grid called residual will be created when this expression is computed. 4. Using the Browse button beside G1, navigate to the Geophysics folder and select Mag_MC.grd. 5. From the list beside G2, select mag_smoothed.grd. 6. Click OK. A new residual grid is created and opens in a display window.
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Lesson 1.6 Filtering Databases and Grids
Figure 1.81 Residual grid
This residual grid represents the high frequency information in the data. Notice the additional features that can now be seen in the lower-right corner.
In this lesson you: Applied a non-linear filter Applied a convolution filter Viewed a hidden channel in the spreadsheet Applied a filter to a grid Subtracted two grids
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Module 2: Creating Maps Module 2 has Four Lessons: Lesson 2.1 Creating a Map
70
Lesson 2.2 Creating Contours
93
Lesson 2.3 Using CAD Tools
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Lesson 2.4 Using Geosoft Seeker
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Lesson 2.1 Creating a Map In this lesson you will: Examine parts of a map Create a base map Use the Map Manager Tool Plot survey lines and symbols Display a single grid and a colour-shaded grid Use the Colour Tool Plot a colour legend bar and a symbol legend
Mapping in Oasis montaj Oasis montaj can be used to create professional quality maps. Physically a map is a special graphic file (*.MAP) containing drawings and images. In practice, however, a map is far more useful than just a venue to display maps and images because it enables you to edit interactively, apply dynamic linking and track the map creation process. When you create or open a map in Oasis montaj, the system displays a Map window in the project. For a new map, the window is initially empty. For an existing map, all map elements are displayed when the window opens.
Parts of a Map When working with maps, you can add, change or delete groups and graphic items (such as lines, text or polygons) or attributes (line thickness, font, etc.) in one or more views. Before working with maps, you should be familiar with the hierarchy of views, groups, graphics items and aggregates in Oasis montaj maps.
Map Views Maps are composed of views. A view is used to organize and display information on a map. Maps consist of a Base view, which uses paper coordinates (i.e. those of the size of paper you choose) with an origin at the bottom left corner of the page, and a Data view, which uses ground coordinates. Map surrounds and graphic items, such as north arrows, titles and scale bars, are plotted in Base views and map coordinates, contours, and grids are plotted in Data views.
Groups A group is a set of graphics elements that make up a graphic component of the map. For example, a line path plot, a contour plot or a profile plot would all be separate graphics groups within the Data View. Examples of map groups in the Base view include:
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Lesson 2.1 Creating a Map north arrows scale bars map surrounds Examples of map groups in the Data view include: images (grids, images, plots) contours coordinates flight lines
Graphics Items Map groups, such as north arrows and contours, are composed of graphic items (lines, polygons and/or text) that you can select individually and add, delete or change (modify attributes).
Aggregates When raster data (grid) is displayed on a map it resides in a special group called an aggregate. An aggregate is another layer that contains grids and images. Aggregates are special because you cannot add or delete elements from them but you can manipulate them. For example, you can modify the colour display interactively using the Colour Tool and add shadows interactively using the Shadow Tool. Below is an example of a map created in Oasis montaj. Figure 2.1 Example map in Oasis montaj
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To create a new map: 1. Select the mag.gdb database. This is the current database. 2. From the Map Tools menu, select New Map then New Map from X,Y. The Data range to map dialog opens and displays the data range determined from the mag.gdb database. Figure 2.2 Data range to map dialog
3. Click Scan data. This will scan the projected X and Y channels of the current database (or selected database if no database is currently open) to determine the data range. 4. Click Next. The Create a new map dialog opens. Figure 2.3 Create a new map dialog
5. For the Map name, enter Mount Palmer. 6. From the Map template list, select landscape ledger or A3. 7. Click the Scale button. This automatically calculates a scale that will fit the data on the map. This value can be rounded to a more efficient number. 8. In the Map scale box, enter 25000 and click Finish. A new, empty map window opens in your project and the Map Navigation toolbar is now active above the map window. The Map Manager tool is displayed to the left of the Map window and can be hidden or pinned.
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Lesson 2.1 Creating a Map
Figure 2.4 Map window with Map Manager tool
Creating a Base Map The layout of your base map can either be a map or a figure style. Figure style maps have a layout with the title, scale bar and north arrow located at the bottom of the map, whereas map style maps have a layout with the title box, scale bar and north arrow along the right side of the map. The following figure shows the difference between the two styles. Figure 2.5 Different base map styles
You can modify and control certain elements of the base map, including the map surround, north arrow, scale bar, reference grids, latitude/longitude annotations, text blocks and titles. In this lesson, you will create a map style base map. To create a map style base map: 1. From the Map Tools menu, select Base Map then Draw Base Map.
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Module 2: Creating Maps The Basemap layout dialog opens. Figure 2.6 Basemap layout dialog
2. From the Map style list, select map. 3. Enter the following margin values: Map margins (cm.) bottom: 2.5 right: 18 top: 2.5 left: 7 inside data margin: 2 4. Click Next. The Full map style base map dialog opens where you can specify the display characteristics of the base map elements. Figure 2.7 Full map style base map dialog
5. For the Reference grid, choose crosses from the dropdown. 6. For the Reference grid spacing, enter 1000. 7. Click inside the Line colour box. The Color dialog opens.
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Lesson 2.1 Creating a Map
Figure 2.8 Color dialog
8. Select the grey colour box and click OK. 9. Click Next. The Map title block dialog opens. Figure 2.9 Map title block dialog
10. In the client text box, enter Geosoft. 11. In the map title text box, enter Regional Magnetic Survey. 12. In the sub-title text box, enter Mt Palmer, Australia and click Finish. The base map is plotted on your new map.
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Figure 2.10 Base map
Map Manager You can use the Map Manager tool to display and edit the Views and Groups in a map. This tool has a tree-like structure that contains two main branches representing the Base view and the Data view. Under each view, a number of groups are listed based on their display priority on the map. The group at the top of the list has highest viewing priority on your map; the group at the bottom of the list has the lowest viewing priority on your map. You can change the priority of a group by dragging it up or down in the tree list. The check boxes in the tree controls and indicates the visibility of an item. The Map Manager is accessed via a tab at the top left of the Map Window; by default it is hidden and will only appear when you hover your mouse over the tab. If you would like the Map Manager to be visible at all times in the map window, you can click on the Auto Hide (pin icon) at the top right corner of the Map Manager.
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Lesson 2.1 Creating a Map
Figure 2.11 Map Window with Map Manager visible
To open the Map Manager Tool: 1. On an open map hover your cursor over the Map Manager tab. The Map Manager window will slide open. 2. To lock the Map Manager in the open position, click on the Auto Hide (pin icon) at the top right corner of the Map Manager. The Map Manager Tool will lock in the open position. Figure 2.12 Map Manager Tool
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Plotting Survey Lines For data that has been collected on a series of lines, such as that in mag.gdb, you may want to display the line paths on your map. To plot the survey line path: 1. From the Map Tools menu, select Line Path. The Line path plot dialog opens. Figure 2.13 Line path plot dialog
2. To set the Horizontal offset of your line path labels, specify 4. Your line paths are plotted on your map with a gap of 4 pixels between the end of the line path and the label text. 3. Click OK. The line paths are plotted on your map.
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Lesson 2.1 Creating a Map
Figure 2.14 Base map with line paths
Now that you have created your base map and plotted the line paths, you will display a grid on it.
Displaying a Grid There are a number of options for displaying grids, include displaying grids, colourshaded grids, and multi-grid composites. Grids appear in the Project Explorer under the Grids section; you can view a grid simply by double-clicking on it. Opening a grid this way opens a view of the grid in a temporary map window. A temporary "grid map" view has limited functionality compared to a "full" map. However, it can also be saved as a map, in which case the map will appear in the Map section of the project explorer. However, care must be taken when saving a “grid map” to a full map, as it does not have a properly defined page size and scale. To display a grid on the map: 1. From the Map Tools menu, select Grid and Image Display then Grid. The Display Grid dialog opens.
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Figure 2.15 Display Grid dialog
2. For Grid name, click the Browse button. 3. From the Geophysics folder, select mag_MC.grd and click Open. 4. Click Current Map. The grid is displayed on your map. You can also select a grid from the Project Explorer and drag and drop it onto your map. Figure 2.16 Base map with lines and mag_MC.grd displayed on the map
Colour Tool With the Colour Tool you can interactively edit the colour display of your gridded data, store your custom colour configurations in specialized colour palette files (*.ITR, *.AGG, *.ZON, *.TBL and *.LUT) and apply the colour palette files to any of your grid image products.
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Lesson 2.1 Creating a Map
To open the Colour Tool: 1. In the Map Manager, locate the grid (AGG_mag_MC). 2. Double-click the (AGG_mag_MC) in the Map Manager. The Colour Tool opens. Figure 2.17 Colour Tool
The Colour Tool enables you to modify the current colour palette. The following are some of the methods you can use to modify the colour palettes: Scroll through the colour palette by clicking the colour rotation buttons. Stretch the range of a specific colour in the colour palette by clicking a colour, holding down the mouse button, and stretching the selected colour up or down on the colour bar. You can create a custom colour palette and apply it to your gridded data. You can then save your customised colour palette in (*.ITR, *.AGG, *.ZON, *.TBL and *.LUT) file formats. Click the Reset button to restore the colours to the settings in the last saved aggregate file. Toggle the Reverse Colours checkbox to flip the colour table. When experimenting with various palettes, you can make your colour changes and save them to a unique aggregate file. You can then reset the palette, experiment with another colour combination and save this combination to another file. When you want to compare a previous palette, simply load the corresponding *.AGG file. When displaying grids, you must specify a colour table. The default colour.tbl file is applied when you display a grid on your map. You may want to experiment with different colour tables to see how they affect the display of your data. To load a different colour table: In the Transform section of the Colour Tool, click Load from file. The Select Colour Ramp dialog opens where you can select from a variety of predefined colour palettes in several categories and formats.
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Figure 2.18 Select Colour Ramp dialog
Displaying a Colour-Shaded Grid The shaded relief image is a common method used to display geophysical and other types of data. This display technique creates a three-dimensional effect using two-dimensional rendering capabilities. The result is useful for checking the quality of the data and for data interpretation. When you create a colour-shaded grid, a new grid file is automatically created with “_s” after the original grid name. For example, mag.grd will become mag_s.grd. To display a colour-shaded grid: 1. From the Map Tools menu, select Grid and Image Display, then Grid. The Display Grid dialog opens. Figure 2.19 Display Grid dialog
2. The grid name is already populated in the field. Select the Apply shadow check box. 3. Check the Add Colour bar check box. 4. Click on the More button and then click on the Shading effect tab.
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Lesson 2.1 Creating a Map 5. Change the value in the Declination field to 90. 6. Click Current Map. The Colour Legend Bar dialog appears. Figure 2.20 Colour Legend Bar dialog
7. For the Title, enter Magnetics. 8. For the Sub-title 1, enter (nT). 9. Click the More button and then click on the Size Definition tab. 10. For the Label Decimals, enter 0. 11. For Maximum bar height (mm), enter 150. 12. Click the Locate button and click the map where you would like to place the lower-left corner of the legend bar. 13. Click OK. The colour legend bar for the shaded relief image is displayed on your map and the grid that is displayed on your map is updated to display as a colour shaded grid.
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Figure 2.21 Mount Palmer map with survey lines and colour-shaded grid and colour legend bar displayed.
To interactively adjust the illumination of the grid: 1. In the Data view of the Map Manager, double-click on the AGG_mag_MC group. The Colour Tool opens. Figure 2.22 Colour Tool
2. Click the Dynamic shadowing button
.
The Shadow Tool dialog opens. Figure 2.23 Shadow Tool dialog
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Lesson 2.1 Creating a Map 3. Click DynaShade. Your cursor changes to the shape of a sun. 4. Click and drag your mouse on your map. As you drag your mouse around the image, the sun illumination angle (inclination and declination) changes depending upon where you click the mouse. For example, clicking closer to the centre of the map will increase the inclination (the maximum is 90 degrees, analogous to a midday sun), whereas the declination will populate with a 0-360 degree angle depending upon where you click in relation to the centre point. 5. To apply the new sun angle settings, click Stop then click OK. You can also adjust the inclination, declination, scale, brightness and contrast values directly in the Shadow Tool dialog. 6. Click Cancel to close the Colour Tool. To move a Base group: 1. From the Map Manager, select the Scale_Bar base group. Re-sizing handles appear around the selected group and your cursor changes to a double arrow when you hover your cursor over the selected group on the map. 2. Click and drag the Scale_Bar above the title block in the lower-right corner. 3. Repeat steps 1 and 2 to move the North_Arrow and COLORBAR_mag_MC according to your own display preference. Next, you will add a logo to your map. To add a logo to your map: 1. From the Map Tools menu, select Grid and Image Display then Image (bmp,tiff,etc.). The Place an image on a map dialog opens. Figure 2.24 Place an image on a map dialog
2. For Image, click the Browse button. 3. From the Files of type list, select JPEG Image (*.jpg). 4. From the Logos and Legends folder, select geosoft-logo.jpg and click Open. 5. For Location, select fit to an area and click Current Map. The Define Area dialog appears. Click OK. 6. Using your mouse, define an area in the top-right corner on the map in which to place the image.
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Module 2: Creating Maps The Geosoft logo is added to your map. As with other base groups, the logo can be moved and resized as needed. Figure 2.25 Map with logo
Next, you will plot symbols for a subset of the geochemical data. Before doing this, however, you will split a channel based on sample types, select which group of samples to process and then examine the group statistics to determine the data ranges to plot. Select the geochem.gdb database file and examine the values in the TYPE channel. The samples are designated as either Auger samples or Soil samples. You will now split this channel into two groups representing these two sample types. This way the samples can be processed separately based on the sample type. To split the TYPE channel: 1. Select the geochem.gdb database. This is now the current database. 2. From the Database Tools menu, select Line Tools then Split on Line Channel. The Split a line based on a line channel dialog opens. Figure 2.26 Split a line based on a line channel dialog
3. For the Line to split, ensure Lgeochemistry:0 is selected. 4. For the Line reference channel, select TYPE.
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Lesson 2.1 Creating a Map 5. To ensure that the fiducial of the first point is set to zero, select the Reset fiducial start values to zero box. It should be checked as we last used this dialog to split the mag database into lines. The fiducial of the first point can be preserved (default), or you can set it to zero by checking the "Reset fiducial start values to zero" box. 6. Click OK. The database updates and displays line LAuger:0. Now that you have split the TYPE channel into Auger samples and Soil samples, you will select which line will be processed. To select lines: 1. Click the line header cell in the top left corner of the spreadsheet. The line currently displayed is LAuger:0. 2. Right-click and select Selections, then Selection Tool. The Line Selection Tool opens. Figure 2.27 Line Selection Tool
3. In the Line List, select LSoil:0 and click Deselect highlight. The LSoil:0 line is no longer selected and will not be included in further processing. 4. Click OK. Now that you have split the TYPE channel into lines and selected which line to process, you will examine the statistics to determine the data range for plotting symbols.
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To view the Auger line statistics: 1. Click the Au channel header cell two times. Only the Au values in the Auger line are selected. 2. Right-click and select Statistics. The Stat Report dialog opens reporting the Au channel statistics for all selected lines in the database, which in this case is only the Auger line. Figure 2.28 Stat Report dialog displaying the Au channel statistics for the Auger line
Note the mean and standard deviation; you will use these values to determine the ranges for plotting the classified symbols.
Plotting Symbols Plotting symbols on your map can be useful for visualizing the location and spacing of your samples. You will now plot symbols representing the Au concentration in the auger samples. To plot symbols: 1. From the Map Tools menu, select Symbols then Colour Range Symbols. The Classified symbol plot dialog opens. Figure 2.29 Classified symbol plot dialog
2. From the Classification channel list, select Au. 3. From the Number of ranges list, select 5.
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Lesson 2.1 Creating a Map 4. Click Ranges. The Specify Ranges dialog opens. Figure 2.30 Specify Ranges dialog
5. Enter the following range values: Parameter
Value
Description
Maximum Value for level 1
25
Mean
Maximum Value for level 2
50
Mean + approx. 1 standard deviation
Maximum Value for level 3
75
Mean + approx. 2 standard deviations
Maximum Value for level 4
100
Mean + approx. 3 standard deviations
6. Click Sizes. The Specify Sizes dialog opens. Figure 2.31 Specify Sizes dialog
7. Enter the following sizes: Symbol Size for level 1: 1 level 2: 1.5 level 3: 1.5 level 4: 2 level 5: 2.5 8. Click OK then click Colours. The Specify Fill Colours dialog opens.
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Figure 2.32 Specify Fill Colour dialog
9. Select the following colours: Select Colour for level 1: blue level 2: green level 3: yellow level 4: orange level 5: red 10. Click OK then click OK again. 11. Click Plot. The colour ranged symbols are plotted on the map. In order to see the ranged symbols more clearly, you may wish to make the shadedrelief image transparent. To adjust transparency: 1. From the Data view in the Map Manager, select the AGG_mag_MC group. 2. Moving the slider to the right, set the Transparency to 45%. The shaded-relief image is now partially transparent and the geochemical symbology are easier to see. Figure 2.33 Colour ranged symbols with transparent shaded-relief image
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Lesson 2.1 Creating a Map Next, you will add a legend describing the graduated colour symbol scheme on your map. To add a colour range symbol legend: 1. From the Map Tools menu, select Symbols then Colour Range Symbol Legend. The Classified Symbol Legend dialog opens. Figure 2.34 Classified Symbol Legend dialog
2. For Title for Legend, enter Au Concentration. 3. For Subtitle for Legend, enter (ppb). 4. Click Locate and the Locate Legend dialog appears. Click OK. Click the map where you would like to place the lower-left corner of the legend. 5. Click Plot. The colour range symbol legend is plotted on your map. As with other base groups, it can be moved and resized as needed. Figure 2.35 Colour ranged symbol legend
Now would be a good time to save your project.
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In this lesson you: Examined parts of a map Created a base map Used the View/Group Manager Tool Plotted survey lines and symbols Displayed a single grid and a colour-shaded grid Used the Colour Tool Plotted a colour legend bar and a symbol legend
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Lesson 2.2 Creating Contours
Lesson 2.2 Creating Contours In this lesson you will: Create quick contours Create multiple contour levels Create exact contours
Creating Contours Contours are lines drawn on your map at specified intervals or multiples of intervals that are derived from a gridded dataset. After you create a grid, you may want to generate contours and display them on your map. The contouring tool in Oasis montaj is specially designed to handle very large dynamic data ranges that are typical of Earth Science datasets. The following contour options are available: Quick - Uses default parameters. Contour - Uses user-specified parameters. This method generates simple or log contours. Log contour - Draws contours on a map using a specified grid in logarithmic mode. Have Control File - ASCII control file enables full cartographic cosmetic control of plotting options. Used for running in batch. If you simply want to create a contour map for basic interpretation, you can use the quick contouring method. This method generates default contours based on the data values in your grid. To create quick contours: 1. From the Map Tools menu, select Contour then Quick. The Contour dialog opens. Figure 2.36 Contour dialog
2. For the Grid file, use the Browse button to locate the mag_MC.grd in the Geophysics folder, and click OK. The contours are plotted on your map. You may want to turn off the display of the line path and colour range symbols. 3. Using the Zoom In tool on the Map Navigation toolbar (found at the top of the map window), zoom to the area shown in the figure below.
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Figure 2.37 Quick contours (zoomed)
4. On the Map Navigation toolbar, click the Auto Recolour Grids button
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This option recolours the displayed grid based on the extent of the grid within the map window. Figure 2.38 Quick contours (zoomed) with Auto Recolor Grids option selected
Next, you will create more customized contours at multiple levels. To create multiple level contours: 1. From the Map Tools menu, select Contour then Contour. The Create a contour plot of a grid dialog opens and remembers the input grid you previously selected.
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Lesson 2.2 Creating Contours
Figure 2.39 Create a contour plot of a grid dialog
2. For the Contouring option, ensure multiples of levels is selected. This option plots levels and their multiples. 3. For Interval level 1, enter 100. 4. For Interval level 2, enter 200. 5. Click OK. The updated contours are displayed on your map. Figure 2.40 Contours at 100 nT intervals
The contours are created every 100 nT (nanotesla). In addition, the level 2 contours specified at an interval of 200 nT have labels and are displayed with a thicker black line style. Depressions are indicated with a triangle. Notice that the contour lines are suppressed in areas where the contours are located close to one another. You will now regenerate the contours and examine additional parameters that control the characteristics of the output.
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To regenerate the contours using additional options: 1. From the Map Tools menu, select Contour then Contour. The Create a contour plot of a grid dialog opens and remembers the parameters you just used. 2. Click Options. The Contour options dialog opens. Figure 2.41 Contour options dialog
3. For smoothing option, select smooth and refine. 4. For suppression density (mm), enter 0. A value of zero means the contour lines will not be suppressed; they will be drawn regardless of how close together they are. 5. For high-low annotation, select none. 6. Click OK then click OK again. The contours are updated based on the options you selected. Figure 2.42 Contours without suppression (zoomed)
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Lesson 2.2 Creating Contours
Click Line Styles in the Create a contour plot of a grid dialog to specify the colour, weight and style of the lines and which levels have labels. You might want to determine the boundary of a particular zone or value in your data. You can create a contour at an exact level to define that boundary on your map. First, you will change the name of the multiple level contour group so you do not overwrite them when you create the exact level contours. To change the name of the contour group: 1. In the Map Manager, select the CONTOUR_mag_MC group. This group is highlighted. 2. Click the group again so it is in editing mode, type Multiple CONTOUR levels mag_MC and press ENTER. To create exact value contours: 1. From the Map Tools menu, select Contour then Contour. The Create a contour plot of a grid dialog opens and remembers the parameters you just used. 2. From the Contouring option list, select exact levels. This option plots only the exact stated contours. 3. For Interval level 1, enter 150 and clear the value of 200 from Interval level 2. This will create a contour at exactly the 150 nT level. 4. Click Line Styles. The Line colour and weight dialog opens. Figure 2.43 Line colour and weight dialog
5. For Line weight-colour level 1, select medium red. 6. Click Back. 7. Click OK. The updated contours are displayed on your map in a medium weight red line. You may want to turn off the display of your multiple level contours. You may also want to turn off the Auto Recolour Grids option on the toolbar.
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Figure 2.44 Contours at 150 nT
Now would be a good time to save your project.
In this lesson you: Created quick contours Created multiple contour levels Created exact contours
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Lesson 2.3 Using CAD Tools
Lesson 2.3 Using CAD Tools In this lesson you will: Create a new group Experiment with the editing tools
Creating a New Group If you are interpreting data, you may want to create an empty group that you can add information to and use as an overlay. For example, you may have created a map from a single grid and want to create an interpretation layer. Since the grid layer (group) cannot be edited directly, you can create an empty group to which you can add annotations. To create a new group: 1. From the Map Tools menu, select CAD Tools then New Group. The Create a new empty group in a view dialog opens. Figure 2.45 Create a new empty group in a view dialog
2. From the View list, select Data. This will add a new group to the Data view. 3. In the New group name text box, enter Interp and click OK. A new empty group labelled Interp is added to the Data tree in the Map Manager and the Map Group Editing toolbar is displayed below the Map Navigation toolbar at the top of the map window. Figure 2.46 Map Group Editing toolbar
When you create a new group, it is automatically added to your map and is in edit mode, meaning that you can start drawing your annotations. A new empty group is outlined with hatch marks indicating that it is editable. Figure 2.47 A new empty group
You can edit any group by selecting it in the Map Manager.
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To select a group for editing: 1. In the Map Manager, double-click the Interp group. The Interp group is now in Edit mode. Alternatively: 1. In the Map Manager select the Interp group. 2. On the Map Manager toolbar, click the Edit Vector Group button ( The Interp group is now in Edit mode.
).
The following table describes the editing tools available on the Map Group Editing toolbar. Table 2.1 Map Group Editing toolbar options
Select Use the arrow tool to select a group or view or items in a group while in editing mode. Click the arrow cursor on the item you want to select for single selection. A sizing box is displayed to indicate that the item is selected. By clicking and dragging it is possible to select multiple items in the dragging rectangle during group editing mode.
Draw Line Use this tool to draw straight lines on a map.
Draw PolyLine Use this tool to draw a segmented line (polyline) on a map. Click to define each point (direction change) along the line. Click the right mouse button and select Done to finish the line.
Draw Rectangle Use this tool to draw a rectangle on a map. Click once to define the upper left corner of the box. Drag the mouse to define the rectangle. Click again to complete the shape.
Draw Polygon Use this tool to draw a polygon on a map. Click to define each point (direction change) along the line. Click the right mouse button and select Done to complete the polygon.
Draw N-Sided Polygon Use this tool to draw a N-sided polygon on a map. Click to display Nsided polygon options dialog and specify the number of sides to plot. Drag the mouse to define the N-sided polygon. Click again to complete the shape.
Draw Circle/Ellipse Use this tool to draw a circle/ellipse on a map. Click once to define the upper left corner of the circle/ellipse. Drag the mouse to define the shape. Click again to complete the shape.
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Lesson 2.3 Using CAD Tools
Add Text Use this tool to add text to a map. Click to define the starting point. Type your message. You can use the sizing handles to change the size of the text box. Click anywhere outside the text box to finish. Select the text box and click the right mouse button to change the text attributes.
Draw Symbol Use this tool to add symbol shapes to your map. Click the location on the map where you want to display the symbol. A symbol is drawn using the current symbol settings. Select the symbol and click the right mouse button to change the symbol attributes.
Get Polygon Attributes Use this tool to acquire a colour or patterns from a polygon on the map. When you select this tool, the cursor will change to include an eyedropper (
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Apply Polygon Attributes Use this tool to apply fill colours and patterns to a polygon. When you use this tool, the cursor image will change to include a bucket (
).
Take some time to experiment with these editing tools.
In this lesson you: Created a new group Experimented with the editing tools
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Lesson 2.4 Using Geosoft Seeker In this lesson you will: Search for Data View Results Download selected data
Geosoft Seeker in Oasis montaj The Geosoft Seeker tool is designed to help you search for and download spatial data stored on global and corporate spatial servers including Geosoft DAP servers and WMS servers, as well as data discovered by the Dapple Search data service and spatial data indexed locally by Desktop Cataloger. From the Seek Data menu, select Seeker to open Seeker and find relevant exploration data. The steps to using the Seeker Tool: 1. Search – Use the search tools to define spatial and text criteria for the data you are seeking. 2. Results – Preview a dataset as a quick thumbnail view or in geographical context using the Preview map, and review metadata. 3. Download – Download selected datasets directly into open map or project. Figure 2.48 Seeker Tool in Oasis montaj
Sign in with a valid Geosoft ID is required in order to access public DAP Servers provided by Geosoft Inc or government sites. If you have not already signed in to your Geosoft ID, using Geosoft Connect, the Sign In with your Geosoft ID dialog will be displayed. Sign in to your Geosoft ID. For more information on your Geosoft ID see the topic Create your Geosoft ID in the Oasis montaj Getting Started How-To Guide, or see the My Geosoft Common Questions (https://my.geosoft.com/commonquestions) web page.
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Lesson 2.4 Using Geosoft Seeker In the following lesson you will search for, examine and download topographic data for the Mt Palmer project area.
Using the Seeker Tool Seeker will behave differently depending on whether you have an open map in your project. Without an Open Map: 1. If the dataset to be downloaded is completely within your area of interest, the entire dataset will be downloaded and displayed, if display option is selected. The dataset extent is used to create the new window. 2. If the dataset to be downloaded overlaps with your area of interest, the dataset will be windowed to the extent of your area of interest and displayed in a new window. The area of interest extent will be used to create the new map. The downloaded dataset will be saved in its original coordinate system. With an Open Map: 1. If you have an open map active the first time you open Seeker in your project, then the Search page will use the map to set your Area of Interest (AOI). You can modify the AOI or update the AOI from the current map extents ( ). 2. If the area of interest that you are using intersects with the open map and the dataset you have selected is completely within your area of interest, then the entire dataset will be downloaded and displayed in the open map. Otherwise, the dataset is windowed using the extents defined by your area of interest. 3. If the area of interest has been re-defined and does not intersect with the open map extents, then downloaded datasets cannot be displayed in the open map and will be displayed in a new window. To use the Seeker tool 1. Make sure that you have Mount Palmer.map selected in your project. 2. On the Seek Data menu, select Seeker. Seeker opens. Because your Mount Palmer map is selected, the search AOI is set to the extents of that map.
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Figure 2.49 Seeker Tool in Oasis montaj
3. In the Text Search field, type Topography and hit Enter. The Seeker Tool moves to the Results page. The Server pane displays the available data sources. 4. Within the Server pane, navigate under the Geosoft Public DAP Server to the SRTM Topography folder. 5. Check the box beside the dataset SRTM World Elevation 3 Arc-Second to select it. 6. Click on the Download radio button. 7. Click on the SRTM World Elevation 3 Arc-Second dataset in the download list to view the Download Properties for that dataset.(See the Download Properties table below for information on the download properties.) 8. Under Coordinate System, click on the Reproject to current map radio button. 9. Click on the Download All button. 10. Click Accept to accept the DAP terms and conditions of use. The grid file will download into your project and is available to use via the Project Explorer and the Map Explorer. It will also automatically display in your map.
Download Properties The Download Properties enable you to specify download options for individual or multiple datasets. Select (highlight) a dataset in the Download list to view the Download Properties for that dataset. The following options are available: Download Properties for all datasets
Destination folder
Use Browse button to specify the destination folder for all the datasets you are downloading. By default the destination is your working project folder.
Download Properties for individual datasets
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Lesson 2.4 Using Geosoft Seeker
Dataset name
Specify a name for the downloaded dataset.
Dataset type
Specify the dataset type for the download dataset, if applicable. Grids may be downloaded as Geosoft Grid (GRD) or ER Mapper (ERS) files. Images may be downloaded as GeoTIFF (TIF), ECW, or in the original file format. GIS files may be downloaded as a MapInfo TAB or ArcGIS Shapefile
Display
Select the display option to Download and open or Download only. Grids will display as single or shaded grids as set by the display options in the application settings.
Windowing
Select the windowing option to Window to the area of interest or Do not window. Windowing is only applicable to spatial dataset types. Note: selecting "Do not window" may result in a large data download.
Coordinate System
Select the coordinate system option to reproject to the current map, if applicable. Otherwise the original coordinate system of the dataset will be used.
Resolution
Select the Recommended or Original Resolution. The recommended resolution depends on area of interest and is not affected by the "Do not window" option. If Recommended is selected then another value in the range shown can be entered. Note: The estimated size is for an uncompressed file. The actual downloaded dataset will be compressed.
In this lesson you: Learned how to use the Seeker tool Downloaded SRTM World Elevation 3 Arc-Second data using the Seeker tool
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Module 3: Creating Gridded Data Module 3 has Three Lessons: Lesson 3.1 Gridding Using the Bi-Directional Method
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Lesson 3.2 Gridding Using the Minimum Curvature Method
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Lesson 3.3 Gridding Using the Kriging Method
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Gridding Data Gridding data is the process of spatial interpolation. The process of gridding takes point data and interpolates to determine the values at the nodes of a grid in between the data points. The resulting interpolated dataset is known as a grid. Figure 3.1 Gridding process
Oasis montaj provides seven methods for interpolating raw XYZ data to create a grid: Minimum Curvature: Interpolates the data by fitting a minimum curvature surface to the raw XYZ data points. This method is ideal when data is sparsely sampled and a relatively smooth variation is expected between data points. Bi-Directional Line Gridding: Rapidly interpolates data that is collected along roughly parallel lines. Kriging: Interpolates data using a geostatistical gridding method to determine a value at each grid node. It first calculates a variogram of the data, which shows the correlation of the data as a function of distance. This method is ideal when data is clustered and randomly distributed. Direct Gridding: Creates a grid from highly sampled data without using any interpolation. It is intended for use with over-sampled datasets such as LIDAR.
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Inverse Distance Weighted Gridding: Interpolates data using the Inverse Distance Weighting (IDW) algorithm. IDW gridding is primarily used to interpolate data where nearby data points are expected to influence one another. Tinning: Creates a Triangular Irregular Network (TIN) file and grids data using the Nearest Neighbour, Linear or Natural Neighbour methods. Trend Enforcement Algorithm: Designed to provide a solution that preserves the character of local trends while eliminating aliasing effects. You can also use the Multiple Channel Gridding tool to grid multiple channels using the same gridding method and parameters.
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Lesson 3.1 Gridding Using the Bi-Directional Method
Lesson 3.1 Gridding Using the Bi-Directional Method In this lesson you will: Determine the cell size Create a grid using the bi-directional gridding method Create a grid using the bi-directional gridding advanced options Use the navigation tools to compare gridding methods
Bi-Directional Gridding The bi-directional gridding method is a numerical technique for gridding parallel survey lines or roughly parallel lines, as illustrated in the following figure: Figure 3.2 Data distribution suitable for bi-directional gridding
Bi-directional gridding is ideal in these situations, especially if there is a high sample density down the lines relative to the line separation. Bi-directional gridding joins narrow features that extend from line to line perpendicular to the line direction. Bi-directional gridding does not use tie lines; if data on the tie lines is important, minimum curvature or kriging should be used. Bi-directional gridding cannot be applied to randomly distributed data. Bi-directional gridding uses linear, minimum curvature or Akima splines to interpolate grid nodes between lines in the direction of the overall trend of the data, which is usually perpendicular to the survey lines. In addition to trend enhancement, bi-directional gridding allows the method of interpolation to be selected independently for the down-line and across-line directions. Geological trends in the data can be emphasised by the appropriate orientation of the grid so that the across-line interpolation is in the direction of the trend. Bi-directional gridding can be 10 to 100 times faster than minimum curvature, and up to 1000 times faster than kriging. Bi-directional gridding has the following strengths: fast for processing large datasets better control in anomalous or high-gradient areas enhances trends in any direction
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Determining Cell Size If you have line data, the cell size should be 1/8 to 1/4 of the nominal line spacing or approximately half the nominal station spacing. If the cell size is not specified, the data points are assumed to be evenly distributed and the default cell size will be calculated as: 1/4 * (sqrt (grid area / # data points)). In this lesson, you will use the Ruler tool to measure the distance between lines in order to determine the cell size for this grid. To determine the cell size: 1. In the Map Manager, turn off the AGG_SRTM World Elevation 3 Arc Second and CONTOUR_mag_MC groups. 2. Zoom in to an area on your Mount Palmer map. 3. In the Map Manager, ensure the PATH_mag group is displayed. 4. Right-click on the map and select Measure Distance. 5. On your map, click on a line path and draw a perpendicular line from one line of data to the next closest line and click again to define the distance, now rightclick and select Done. The measured distance is displayed on the status bar of the map window. The line spacing in this dataset is approximately 100m; using 1/4 of the line spacing, the recommended cell size for this dataset is 25m. Now that you have determined the cell size to use, you will create a grid using the bi-directional method. You will run this twice; first using the default parameters, and then again adjusting some of the advanced parameters. To grid data using the bi-directional method: 1. Select the mag.gdb database. 2. From the Grid and Image menu, select Gridding then Bi-Directional Line Gridding. The Bi-directional gridding of line data dialog opens. Figure 3.3 Bi-directional gridding of line data dialog
3. For the Channel to grid, select Mag_edited. 4. For the Output grid, enter mag_BG. The file extension *.grd will be added automatically. 5. For the Grid cell size, enter 25. This is one quarter of the line spacing you measured above. 6. Click OK.
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Lesson 3.1 Gridding Using the Bi-Directional Method The gridded data created using the bi-directional gridding method opens in a display window in your project and the grid is added to your Project Explorer. Figure 3.4 Bi-directional grid
You can also use the Multiple Channel Gridding tool to grid multiple channels using the same gridding method and parameters. Before you grid the data again using the bi-directional advanced gridding options, you will measure the angle of the geological features or trends in the data. The angle that you measure will be entered as the trend angle. To use the measure angle tool: 1. Zoom in to the middle section of the mag_BG grid. 2. Right-click and select Measure Angle. 3. Click on the map and draw a horizontal line to the right. This represents the X-axis and should be drawn as horizontal as possible. The angle will be measured relative to this line. 4. Click again to draw another line along the geological trend in the data. The angle between these two lines is displayed on the bottom right of the status bar of the map window. The trend of this geological feature is approximately 100 degrees. You will now re-grid the data and specify this value as the trend angle in the advanced options.
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Figure 3.5 Measuring the trend angle
To grid data using the bi-directional gridding advanced options: 1. From the Grid and Image menu, select Gridding then Bi-Directional Line Gridding. The Bi-directional gridding of line data dialog opens and remembers the parameters you used the first time. 2. For the Output grid, enter mag_BG_trend100. 3. Click Advanced. The Advanced Gridding options dialog opens where you can specify advanced bi-directional gridding options.
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Lesson 3.1 Gridding Using the Bi-Directional Method
Figure 3.6 Advanced Gridding options dialog
The following are some of the key parameters that control the creation of the grid surface: Maximum line separation: The maximum separation distance allowed between lines. Areas enclosed by lines that are farther apart than this distance are represented by dummy values in the output grid. By default, the maximum separation is set to 1.5 times the average line separation. If the line to line separation maximum is too narrow, the output grid will consist of data strips that frame each survey lines, with blank grid areas in between. The width of the data strips depends on the number of cells that extend beyond the edges of the data. Maximum point separation: The maximum separation distance allowed between stations on a line. Gaps in lines wider than the station to station maximum are not interpolated. The default is to use the maximum line to line separation value. If the entered value is smaller than the output cell size, then internally it is increased to be equal to the output cell size. Data pre-sort option: This sorts each line so that all data points are consecutive in the gridding direction. You should exercise caution when presorting because data entry errors may result in the data being sorted out of order. The remove back-track data option causes data in the line that appears to backtrack to be removed. Use this option when processing airborne geophysical data. Trend angle: This parameter is intended to enhance geological features in the direction specified. The angle is measured counter-clockwise relative to the positive X-axis (which normally points to the east). Typically, you want to enhance features that are perpendicular to the survey line direction. If the trend angle is not specified, the default is to calculate the angle perpendicular to the survey line direction. For example, if your survey lines are
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oriented at N30E, the default trend angle will be calculated as either -30 degrees or 150 degrees. 4. For the Trend angle, enter 100. 5. Click Finish. The gridded data created using the bi-directional gridding advanced options opens in a display window in your project. Figure 3.7 Bi-directional grid with advanced options
Both grids created using bi-directional gridding should now be open in your project window. You will now compare the two to observe any differences created by use of the Advanced trend parameter. To set up the display for comparison: 1. Minimize all your database and map windows and ensure the mag_BG and mag_BG_trend100 grids are displayed. 2. Select the mag_BG window to make it the active window. 3. From the Window menu, select Tile Vertically. 4. On the Grid Toolbar at the top of the Grid window, click the Change Extent on All Maps button
.
This applies all map navigation commands to all the open map windows in the project. When you zoom in one window, you will automatically zoom to the same location in all other open windows.
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Lesson 3.1 Gridding Using the Bi-Directional Method Take some time to navigate around the maps, comparing the trends and outline of the major anomalies (magnetic highs). You should not actually notice much difference at all between the two grids. Recall that bidirectional gridding is designed to interpolate in the direction perpendicular to the survey lines. In this case, with EW trending survey lines, that angle is 90 degrees counterclockwise to X (east). You measured the strike of the main anomalies in the data for a trend of 100 degrees counterclockwise to East. There is not a large enough difference between the two angles, hence there is no marked differences between the two grids.
In this lesson you: Determined the cell size Created a grid using the bi-directional gridding method Created a grid using the bi-directional gridding advanced options Used the navigation tools to compare grids
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Lesson 3.2 Gridding Using the Minimum Curvature Method In this lesson you will: Create a grid using the minimum curvature method Examine the grid properties Create a grid using the minimum curvature advanced options
Minimum Curvature Gridding Minimum curvature gridding is a gridding method that fits a smoothest possible surface to the data points. It is best used when data is randomly distributed, when data is sampled along arbitrary lines or if you want to include tie lines. The following figure illustrates these types of data: Figure 3.8 Data distribution suitable for minimum curvature gridding
If the data is relatively smooth between sample points or survey lines, minimum curvature gridding should be used. If the data may be variable between sample locations, or is known to be statistical in nature (such as geochemical data), is poorly sampled or clustered, use the kriging method. Minimum curvature gridding has the following strengths: works with any spatial distribution of data does not impose a directional bias
Determining Cell Size If your data is distributed as random points, the cell size should be 1/4 to 1/2 of the nominal sample interval. If the cell size is not specified, the data points are assumed to be evenly distributed and the default cell size will be calculated as: 1/4 * (sqrt (grid area / # data points)) Because our geochemical data is randomly distributed, it is difficult to manually measure the nominal sample interval. In this lesson, you will grid the geochemistry data using the minimum curvature method and have the algorithm determine the cell size for you. You will then run it again after adjusting some of the advanced parameters to optimise the output grid.
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Lesson 3.2 Gridding Using the Minimum Curvature Method
To grid data using the minimum curvature method: 1. Make sure the geochem.gdb is the current database. 2. From the Grid and Image menu, select Gridding then Minimum Curvature. The Minimum Curvature Gridding dialog opens. Figure 3.9 Minimum Curvature Gridding dialog
3. From the Channel to grid list, select Au. 4. For the Output grid, enter Au_MC. The Grid cell size parameter is optional. By leaving it blank, the cell size will be calculated automatically. 5. Click OK. The gridded data created using the default settings for the minimum curvature method opens in a display window in your project. Figure 3.10 Minimum Curvature grid
The holes in the grid correspond to areas containing no data points in the original data. Later in this lesson you will re-grid the data using several advanced options. One of these options is the blanking distance; this is the distance within which missing grid cell values will be interpolated. This parameter can be adjusted to fill in holes in the grid if required. Now you will examine the properties of the grid that you just created.
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To examine the grid properties: 1. From the Grid and Image menu, select Properties. The Grid Properties dialog opens. Figure 3.11 Grid Properties dialog
2. From the Grid list, select Au_MC.grd and click Next. The Grid Properties dialog opens. Notice the calculated X and Y point separation (the cell size) is 23.08 m. Figure 3.12 Grid Properties dialog
You can also open the Grid Properties dialog by right-clicking a grid in the Project Explorer and selecting Properties. 3. Click Stats. The Grid Statistics dialog opens. Figure 3.13 Grid Statistics dialog
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Lesson 3.2 Gridding Using the Minimum Curvature Method 4. Click Histogram. The View Histogram dialog opens and displays the grid histogram. Figure 3.14 View Histogram dialog
Look at the statistics and the histogram. The data appears to be logarithmically distributed (log-normal). While the minimum curvature method attempts to create the smooth (linear) surface, because the Au data is log distributed, the output grid does not fit the original data very well. If you compare the grid statistics to the channel statistics of the original Au data, you can see that these values are different. For example, the original data has a minimum of 2 (ppb), where as the grid minimum is -13. Given that this is geochemical data, a minimum value that is negative is not realistic. You will now run the minimum curvature gridding again. This time you will specify a grid cell size of 25 m. You will also examine some of the advanced options, including the log option and the blanking distance. To grid data using the minimum curvature advanced options: 1. From the Grid and Image menu, select Gridding then Minimum Curvature. The Minimum Curvature Gridding dialog opens and remembers the parameters you used the first time. 2. For the Output grid, enter Au_MC_log.grd. 3. For the Grid cell size, enter 25. 4. Click Advanced. The Minimum Curvature Gridding – Advanced Options dialog opens.
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Figure 3.15 Minimum Curvature Gridding – Advanced Options dialog
The following are some of the key parameters that control the creation of the grid surface: Log Option: The logarithm (base 10) of the data can be gridded rather than the original data. Once gridded, the output grid can be stored as either the logarithmic data or it can be transformed back to the original units. Gridding the log of the data can be a very effective way to reduce distortion due to highly skewed data such as geochemical data. Blanking Distance: All grid cells farther than the blanking distance from a valid point will be blanked out in the output grid. The default is the nominal sample interval, i.e. 2*(sqrt (grid area / #data points)). This parameter should be set to just greater than the maximum sampling interval through which interpolation is desired. If there are too many holes in the resulting grid, increase the blanking distance appropriately. Tolerance: The tolerance required for each grid cell (%). The default is 0.1 percent of the range of the data. Decrease the tolerance for a more accurate grid. % Pass Tolerance: The required percentage of points that must pass the tolerance. The default is 99.0 percent. Increase this percentage for a more accurate grid. Maximum iterations: Iterations at the finest coarseness level will stop when the maximum number or iterations is reached (default is 100). At each greater coarseness, the maximum iterations is reduced by 2. Increase this value if more iterations are required to produce a more accurate grid. Internal tension: The degree of internal tension (between 0 and 1). The default is no tension (0), which produces a true minimum curvature grid. Increasing
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Lesson 3.2 Gridding Using the Minimum Curvature Method
tension can be used to prevent overshooting of valid data in sparse areas, although curvature in the vicinity of real data will increase. 5. From the Log option list, select log, save as linear. Because this is highly skewed geochemical data, the log option will be used. The log option transforms the data into log space, generates the grid based on the transformed data and outputs the resulting grid back in linear space. Procedure Note: If you use any Log option other than "linear", you should set the "Log Minimum" value to the minimum desired value in the output grid. In practice this should be the minimum value in the data from which you are generating the grid. 6. For the Blanking Distance, enter 225. All grid cells within this distance from a valid point will be interpolated. Grid cells that are further than this distance, will be left blank in the output grid. You will use the intelligent defaults for the remaining parameters. 7. Click Finish. The gridded data created using the advanced options for the minimum curvature gridding method opens in a display window in your project. Figure 3.16 Minimum curvature grid with log option and blanking distance of 225 m
8. Tile the Au_MC.grd and the Au_MC_log.grd grids and zoom in to the upperleft corner.
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Figure 3.17 Left, Au_MC.grd; right Au_MC_log.grd
Note the "hole"has been filled in on the latest grid. Check the grid and compare the grid statistics to the database statistics to determine whether you think the latter result is a better quality grid than the former.
In this lesson you: Created a grid using the minimum curvature method Examined the grid properties Created a grid using the minimum curvature advanced options
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Lesson 3.3 Gridding Using the Kriging Method
Lesson 3.3 Gridding Using the Kriging Method In this lesson you will: Compute the variogram Adjust the variogram parameters Create a grid using the kriging method
Kriging Kriging is a geostatistical gridding technique for random data, non-parallel line data or orthogonal line data, as illustrated in the following figure: Figure 3.18 Data distribution suitable for kriging
Use the kriging method if the data are variable between sample locations, known to be statistical in nature, poorly sampled or clustered. Kriging is ideally suited to geochemical or other geological sample-based data; it is rarely used with geophysical data, which tends to vary smoothly between data points. It first calculates a variogram of the data showing the correlation of the data as a function of distance. The greater the distance between data points, the greater the variation between the points. Based on the variogram, you can select a model that best defines the variance of the data. Because kriging can be slow, the size of a dataset may be a limiting factor in choosing kriging. Kriging has the following strengths: ideal for clustered data better control in anomalous or poorly sampled areas You will now use the kriging method. You will first compute the variogram, adjust the advanced options and then create the grid. To compute the variogram: 1. From the Grid and Image menu, select Gridding then Kriging. The Kriging dialog opens.
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Figure 3.19 Kriging dialog
2. For the Channel to grid, select Au. 3. For the Output grid, enter Au_K. 4. For the Grid cell size, enter 25. 5. Click Advanced. The Kriging - Advanced Options dialog opens. Figure 3.20 Kriging - Advanced Options dialog
The following are some of the key parameters that control the creation of the grid surface: Range/Slope: For spherical, Gaussian and exponential models, the range is the distance at which the variogram model reaches the sill value. Beyond the range, the data is uncorrelated. For the power model, this is the rate of climb, or slope for a linear model. Nugget: The nugget is the average error in each data point and is indicated by the intersection of the variogram model with the h=0 axis. The default is 0. Sill: This is the level at which the variogram becomes uncorrelated, or goes flat. The sill must be specified for the spherical, power and Gaussian models. Strike and Strike weight: These parameters control anisotropic gridding.
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Lesson 3.3 Gridding Using the Kriging Method 6. For Name of output variogram file, enter Au. 7. For Log option, select log, save as linear. This option will grid in log space and output the results in linear space. 8. For the Blanking Distance, enter 225. 9. For Variogram model, select spherical. 10. Click Variogram Only. The variogram is plotted and displayed in the variogram map window. Figure 3.21 Variogram
In general, the output variogram is good at matching the overall character of the data. Ideally, the red curve representing the variogram model should match the black line representing the observed data. Next, you will adjust the variogram parameters and then create the gridded data. To adjust the variogram parameters: 1. From the Grid and Image menu, select Gridding then Kriging. The Kriging dialog opens and remembers the parameters you used the first time. 2. Click Advanced. 3. For Range/Slope, enter 1300. 4. For Sill, enter 0.115. 5. Click Variogram Only. A File Validation window opens asking to overwrite the existing variogram. 6. Click Yes. The variogram is updated based on the adjusted parameters.
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Figure 3.22 Updated variogram
The updated variogram has a slightly better fit to the observed data. It has been shifted down and to the right. Now you will create the grid. To create the grid based on the variogram: 1. From the Grid and Image menu, select Gridding then Kriging. The Kriging dialog opens and remembers the parameters you used the first time. 2. Click OK. The gridded data created using the kriging method opens in a display window in your project.
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Lesson 3.3 Gridding Using the Kriging Method
Figure 3.23 Grid created using the kriging method
Using the navigation tools described earlier, compare the grids created using the three different gridding methods. Now would be a good time to save your project.
In this lesson you: Computed the variogram Adjusted the variogram parameters Created a grid using the kriging method
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Module 4: Working with Sections Module 4 has Four Lessons:
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Lesson 4.1 Creating Sections from Array Data
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Lesson 4.2 Creating Stacked Sections from Array Data
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Lesson 4.3 Creating Sections from a Plan Map
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Lesson 4.4 Import Section Grids into a 3D View
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Lesson 4.1 Creating Sections from Array Data In this lesson you will: Create section maps from Array data
Creating Sections from Array Data Oasis montaj has a number of features that enable you to create georeferenced section grids from array data, along with different styles of section maps. In this lesson you will: Create section maps from Array data Create maps with stacked 2D sections Create sections from a plan map Import section grids into the 3D viewer To create section maps from array data: 1. Make sure that the Mt Palmer Conductivity database is selected. Ensure you have selected the line(s) in the database that you want to use for your section(s). 2. From the Section Tools menu, select Create Section(s) from Data. The Create Section(s) from Data dialog opens.
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Lesson 4.1 Creating Sections from Array Data
Figure 4.1 Create Section(s) from Data dialog
1. Using the From radio buttons, select Database. 2. Using the Plot dropdown list, select the lines to plot as Selected lines. 3. Using the Data array dropdown list, select Mt_Palmer_Conductivity. The Depth array dropdown list becomes inactive because you earlier attached depth information to the array channel. 4. Click the More button. 5. Go to the Grid tab. From the Display method dropdown list, select inverse distance weighting. 6. Go to the Map layout tab. In the View width field, enter a value of 20. In the View height field, enter a value of 5. 7. Go to the Top profile tab. From the Topography dropdown list, select Elevation. Check the Plot top of section and Plot location symbols check boxes. 8. Now, click on the Calculator icon next to the Horizontal scale field. The field will populate with an appropriate scale based on the specified View width and View height. 9. From the Surrounds dropdown list, select Custom. 10. Click OK. The grids for each section are created and displayed in temporary maps within the project workspace. The Draw Section Surround dialog appears.
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Figure 4.2 Draw Section Surround dialog
4. Go to the Legend tab. In the Title field, enter "Mt Palmer Conductivity". 5. Click OK to plot the section maps. The section maps are displayed in the project workspace. Figure 4.3 Section map for Mt Palmer Conductivity Line 1
In this lesson you: Created section maps from array data
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Lesson 4.2 Creating Stacked Sections from Array Data
Lesson 4.2 Creating Stacked Sections from Array Data In this lesson you will: Create maps with stacked 2D sections
Creating Stacked Section Maps from Array Data Stacked section maps comprise a single map that contains multiple sections. Multiple sections can be aligned within a map in various ways, including in their relative georeferenced positions, depending upon whether the sections are parallel or not. To create a stacked section map from array data: 1. Make sure that the Mt Palmer Conductivity database is selected. Ensure you have selected the line(s) in the database that you want to use for your sections(s). 2. From the Section Tools menu, select Create Section(s) from Data. The Create Section(s) from Data dialog opens. Note that the settings and parameters are remembered from the previous section plotting exercise.
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Figure 4.4 Create Section(s) from Data dialog
3. In the Sections per map field, enter a value of 3. 4. In the Section map prefix field, enter the term "Stacked". 5. In the More section, go to the Extents tab. From the Alignment dropdown, select Align on eastings. "Alignment" can be chosen whenever your sections are parallel, in order to display them in relative position. 6. Click the OK button. The Draw Section Surround dialog appears. 7. Click OK to plot the stacked section map.
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Lesson 4.2 Creating Stacked Sections from Array Data
Figure 4.5 Stacked Section Map
In this lesson you: Created maps with stacked 2D sections
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Lesson 4.3 Creating Sections from a Plan Map In this lesson you will: Create a section map from a plan map
Creating a Section Map from a Plan Map The Create Section(s) from plan map tool enables you to create a cross sectional view with coordinates, reference grids, a plan view, topography profiles etc., without requiring the drillhole plotting extension. The resulting section maps can be used to: Plan drillholes interactively Display section grids or voxel slices Display geosurface slices in section Digitize geological interpretations to be used in wireframing In this exercise you will create a section from an existing plan map and plot a slice from a magnetic susceptibility voxel in the section. To create a section from a plan map: 1. Ensure that the Data layer of the Mt Palmer.map is selected in your project. 2. On the Section Tools menu, click Create Section(s) from Plan Map. The Section Parameters dialog will appear. Figure 4.6 Section Parameters dialog
3. On the Page Layout tab, check the Plot legend check box. 4. Go to the Section Location tab. In the Section Azimuth pane, ensure that the E-W radio button is selected and click on the Define button next to it. When you hover your mouse over the Mt Palmer map, the mouse cursor changes to a cross-hair. 5. Click the mouse once anywhere on the western edge of the map.
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Lesson 4.3 Creating Sections from a Plan Map 6. Move the mouse to the eastern edge of the map, as you do this a line defining the rectangular extent of the section window appears. 7. When you are happy with the extent of the section window, click the mouse once more. If required, you can now adjust the final position of the section window. Click to finish. 8. In the Thickness field within the Location and Orientation pane, enter a vale of 100. 9. Go to the Reference Grid tab. 10. From the Grid Options, select Crosses. 11. In the East, North and Elevation boxes, enter a value of 500. 12. Go to the Topography tab. 13. Check the Plot topography on section option and click the first Browse button. The Select File Type dialog appears. Figure 4.7 Select File Type dialog
14. Select Gridded topography (GRD, DEM) and click OK. 15. From the Topography folder, select Topo.grd and click Open. 16. Go to the Plan View tab. 17. Check both the Plot plan view and Include selected map groups check boxes. 18. From the Not selected list, select Data\AGG_mag_MC and click the > button. 19. Go to the Slices tab. 20. Check the Plot voxel slice check box and click Browse. 21. From the Geophysics folder, select Mt Palmer Susceptibility.geosoft_ voxel and click Open. 22. Click OK to plot the section map. Figure 4.8 Section Map
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The image shown in the section is a slice from a magnetic susceptibility voxel model. This slice is along the centre plane of the section window. The image in the plan view window is TMI.
In this lesson you: Created a section map from a Plan map
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Lesson 4.4 Import Section Grids into a 3D View
Lesson 4.4 Import Section Grids into a 3D View In this lesson you will: Import section grids into a 3D view
Importing Section Grids into a 3D View All of the grids created during the previous Section Tools exercise are georeferenced in 3D space. Therefore they can be very easily imported into a 3D map. The 3D viewer provides an integrated environment that includes all the tools, functions and settings to create a 3D map. You can add any number of 3D and 2D views and groups to our map, including planes, relief surfaces, grids, voxels, isosurfaces, drillholes and 3D import file formats. You can create a new 3D map or add a 3D view to an existing map. Once a 3D map and view are created, there are several means by which to import the grids into the 3D view. In this exercise you will create a 3D view and import section grids into it. We will look at the 3D viewer in more detail in a later lesson. To import section grids into a 3D view 1. From the 3D menu, select New 3D View. The New 3D View dialog opens. Figure 4.9 New 3D View dialog
2. For 3D View name, we can accept the default, Mt Palmer 3D.geosoft_3dv and click OK. 3. The 3D viewer opens, which enables you to manipulate both the data and the perspective of the 3D view. Figure 4.10 The 3D Viewer
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4. In the Project Explorer window, expand the Grids list. 5. Within the list of grids will be the three that were created, L1_IDW.grd, L2_ IDW.grd and L5_IDW.grd. 6. Use control select to select the three grids and then drag and drop them into the 3D viewer. The sections grids open in the 3D Viewer. Figure 4.11 Section grids within the 3D viewer
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Lesson 4.4 Import Section Grids into a 3D View
In this lesson you: Imported section grids into a 3D view
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Module 5: Creating a 3D Map Module 5 has Six Lessons:
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Lesson 5.1 3D Viewer
144
Lesson 5.2 Drape Data on a Relief Surface
146
Lesson 5.3 Working with Voxels
149
Lesson 5.4 Clipping Voxel Extents
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Lesson 5.5 Working with Isosurfaces
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Lesson 5.6 Creating Snapshots and Animations
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Lesson 5.1 3D Viewer In this lesson you will: Open a 3D view Plot topography in your 3D view
About the 3D Viewer The 3D Viewer provides an integrated 3D environment that includes all of the tools, functions and settings to create a 3D map. Using the 3D Viewer you can add any number of 3D and 2D views and groups to your map, including planes, relief surfaces, grids, voxels, isosurfaces, drillholes, 3D symbols, a variety of 2D map tools, and 3D import file formats. You can create a new 3D view or open an existing 3D view. In this lesson you will create a 3D view, explore the navigation tools and import and manipulate various data within the 3D view. To open a 3D view and plot topography 1. Ensure your 3D View, Mt Palmer 3D.geosoft_3dv, which we created in the previous lesson, is open in your current project. The 3D view should have the three Conductivity sections displayed. Now you are going to add some topography, in the form of a relief surface. 2. From the Add to 3D menu, select Relief Surface. The 3D Surface from a grid dialog opens. Figure 5.1 3D Surface from a grid dialog
3. For Surface relief grid, click the Browse button. 4. From the Topography folder, select SRTM World Elevation MGA 90m.grd and click Open. 5. For the Colour image/grid, click the Browse button. 6. From the Topography folder, select SRTM World Elevation MGA 90m.grd and click Open. 7. For Colour table, click inside the colour ramp. The Select Colour Ramp dialog opens.
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Lesson 5.1 3D Viewer 8. Using the Category dropdown list, select Topography. Then from the list of names, select the elevation.tbl and click OK. 9. Click OK on the 3D Surface from a grid dialog. The relief grid is displayed in the 3D Viewer. There is not much topographic variation in the project area. If you want to increase the vertical exaggeration of the relief surface in order to accentuate what variation there is, you can do so by selecting it in the 3D Manager and adjusting the "Scale" field in the Attributes pane. You can change the vertical exaggeration of all data in the 3D View by adjusting the Z-Axis Scaling in the Rendering Settings (Tools & Settings>>Rendering Settings). Figure 5.2 Relief grid in 3D Viewer
In this lesson you: Opened a 3D View Plotted topography in your 3D view
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Lesson 5.2 Drape Data on a Relief Surface In this lesson you will: Review interactive tools Drape data on a relief surface The following interactive tools are provided to navigate the display of your data in 3D: Table 5.1 3D Manager Tools
Icon
Tool
Description
Add Plane
Click this button to add any number of planes to the 3D view.
Section View
Click this button in order to create a section view, which is a 3D reference plane that you can manipulate to any orientation. From this plane you can generate section maps and also plan new drillholes.
Table 5.2 3D Navigation Tools
Icon
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Tool
Description
Shadow Cursor On
To toggle the visibility of the shadow cursor On/Off
Pan
To move the entire displayed view
Zoom In/Out
To zoom in and out of the displayed view
Rotate
To rotate the displayed view 360 degrees in all directions
Centre to Window
To centre the current 3D view in the 3D Viewer display window
Automatic Zoom On/Off
To automatically adjust the 3D view as objects are selected/deselected in the tree control
Zoom to Full Extents
To centre the 3D view based on the currently selected objects in the tree control
Automatic Redraw On
To refresh/redraw the 3D view automatically after changes are made
Redraw
To refresh/redraw the 3D view in the 3D Viewer window
North View
To set the observation point for the current view to directly north (looking south)
South View
To set the observation point for the current view
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Lesson 5.2 Drape Data on a Relief Surface Icon
Tool
Description to directly south (looking north)
East View
To set the observation point of the current view to directly east (looking west)
West View
To set the observation point of the current view to directly west (looking east)
Top View
To set the observation point of the current view to directly above (looking down)
Bottom View
To set the observation point of the current view to directly below (looking up)
User Defined View
To specify the inclination and azimuth of the view
Perspective/ Orthographic View
To select to display as either a perspective view or an orthographic view.
Create Snapshot
To create a snapshot of your current view.
Create Animation from Snapshots
To create an animation from a series of snapshots and export as, *.WMV or *.MP4 movie file format.
Right-click in the 3D Viewer for quick access to some of these navigation tools. You can also zoom in and out using the track wheel on your mouse. Take some time now to experiment with the 3D navigation tools. Next, you will drape magnetic data over the relief surface. To drape data on the relief surface: 1. From the Add to 3D menu, select Relief Surface. The 3D Surface from a grid dialog opens. 2. Using the Browse button for Colour image/grid, locate the Geophysics folder and select Mag_MC.grd. 3. For Colour table, click inside the colour ramp. The Select Colour Ramp dialog opens. 4. Using the Category dropdown list, select Geophysics. Then from the list of names, select the colour.tbl and click OK. 5. Click OK on the 3D Surface from a grid dialog. The mag data is now draped on top of the relief grid.
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In this lesson you: Reviewed interactive tools Draped data on a relief surface
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Lesson 5.3 Working with Voxels
Lesson 5.3 Working with Voxels Add a voxel to your 3D view Manipulate the voxel colour distribution
Geosoft Voxels The term Voxel is short for "volume pixel", the smallest distinguishable cubic part of a three dimensional image, in effect the 3D counterpart if the 2D pixel. At Geosoft, the Voxel is a 3D volume made of of a number of voxels, each containing a volume and a unique data value that represents some measurable quantity, such as magnetic susceptibility, density or conductivity. Voxels can be created by numerous means; by 3D inversion and geological modelling in both Oasis montaj and other software. Within Oasis montaj, they can be created using several gridding methods, such as Kriging, Inverse Distance Weighting and Direct Gridding. These options can be found within the 3D gridding option, either within the 3D menu within Oasis montaj, or from the Voxel menu in the 3D viewer. You will now open a voxel of magnetic susceptibility in the 3D viewer. To add voxel to 3D view 1. From the Add to 3D menu, select Voxel. The Add a Voxel to 3D dialog opens. 2. For the Voxel name, click the Browse button. 3. From the Geophysics folder, select Mt Palmer Susceptibility.geosoft_ voxel and click Open. 4. Click the OK button. The voxel appears in the 3D viewer.
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Figure 5.3 Voxel displayed in 3D View
To manipulate the voxel colour distribution 1. Ensure VOX_mt palmer susceptibility is selected in the 3D Manager. 2. On the Attributes tab, click the Colour Tool button. The Voxel Colour Tool dialog appears. Figure 5.4 Voxel Colour Tool
3. Click on the Use a linear distribution ( ) button. The Linear Transform dialog appears, click OK. 4. Click OK to exit the Voxel Colour Tool. The voxel colour in the 3D Viewer is updated.
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Lesson 5.3 Working with Voxels
Figure 5.5 3D Viewer with updated voxel colour distribution
In this lesson you: Added a voxel to your 3D view Manipulated the voxel colour distribution
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Lesson 5.4 Clipping Voxel Extents In this lesson you will: Change the visual extent of the voxel by interactive clipping
Manipulate Voxel Extents by Clippping By using the Clipping pane within the 3D Viewer, voxels and other 3D data can be clipped in any orientation. Voxels have an additional clipping option in that enables you to clip the voxel using its data value. For voxels, data values can be clipped interactively by moving the sliders on the Data bar. Data values can also be clipped manually by specifying a data range in the text boxes provided (minimum value on the left, maximum value on the right). To manually specify the data clip region, click inside the Data text boxes and specify the minimum and maximum values and then press the Enter key. The voxel will be clipped to your specified data extent. To interactively modify the data clip region, use your cursor to move the bottom sliders (bottom inward facing arrows) from either end of the slider bar, as shown in the image below: Figure 5.6 Clipping tab showing Data slider
Your voxel data range will be updated interactively as you move the Data slider bars. Note that you can move the data range bar (centre bar), which will maintain the data range while interactively changing the voxel data values. To change the visual extent of the voxel by interactive clipping 1. In the 3D Manager, turn off the item Surface_SRTM World Elevation 90m. 2. Select VOX_mt palmer susceptibility in the 3D Manager. 3. Select the Clipping tab below the 3D Manager.
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Lesson 5.4 Clipping Voxel Extents
Figure 5.7 Clipping pane below the 3D Manager
4. On the Y axis, click on the left slider icon and drag it approximately half way to the right (~6530000N). 5. Check the Modify Orientation check box underneath the Y axis slider. 6. In the Dip field, enter a value of 75. Rotate the 3D view to best observe the dip change. The voxel extents updates accordingly.
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Figure 5.8 Clipping pane in the 3D Viewer
To change the visual extent of the voxel by data clipping 1. Reset the clipping sliders so that the voxel is fully visible. 2. In the left (minimum) Data field , enter a value of 0.015 and press the Enter key. This interactively modifies the low value of the Data clip region. Only the voxel cells valued at 0.015 SI or greater will be visible.
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Lesson 5.4 Clipping Voxel Extents
Figure 5.9 Clipped data value of 0.015
In this lesson you: Changed the visual extent of the voxel by interactive clipping
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Lesson 5.5 Working with Isosurfaces In this lesson you will: Create and display an isosurface
Isosurfaces An isosurface is a 3-dimensional surface that passes through points of equal value. Isosurfaces can be thought of as 3D contours. Isosurfaces are written to a geosurface file that is able to save many isosurfaces extracted from the same voxel. This enables you to copy a single file with all its isosurfaces to another location, or to easily share your results with colleagues to collaborate on projects. Using Geosoft tools, there are three different ways to create isosurfaces from a voxel: Visually clip the minimum data values from a voxel and automatically extract an isosurface at the specified clip value. Create a single isosurface at a specified value. Automatically create multiple isosurfaces using a linear, log or user-specified distribution. To create and display the isosurface: 1. Click on the Define isosurface using data clipping values icon within the clipping pane (
).
The Create Isosurface from Voxel dialog opens and is automatically populated with the Input voxel name, the Output geosurface name, the Surface Properties value (this is the minimum data clip value you specified) and the Colour. Figure 5.10 Create Isosurface from Voxel dialog
2. Change the Colour to grey. 3. Check the Create closed surface check box. 4. Click OK.
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Lesson 5.5 Working with Isosurfaces The geosurface (SURF_Mt Palmer Susceptibility) and the isosurface (Isosurface >0.015) are added to the 3D Viewer. 5. Turn off the display of the VOX_mt palmer susceptibility layer to see the isosurface more clearly. Figure 5.11 Isosurface at a value of 0.015
In this lesson you: Created and displayed an isosurface
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Lesson 5.6 Creating Snapshots and Animations In this lesson you will: Create snapshots from the 3D view Manage snapshots Create an animation from the snapshots
3D Snapshots and Animations 3D View snapshots are like bookmarks of individual states of your current 3D View; they enable you to capture and return to a favorite location, or state, of a view quickly and easily. For example, if you are working on a complex 3D model and would like to share specific views with your colleagues, you can create a number of snapshots that will save the viewing angle and location, the 3D View extents and display settings, as well as the 3D groups visibility, transparency and clipping settings. Use the Create Animation tool from Snapshots dialog to create an animated sequence (or movie) based on selected snapshots associated with the current 3D View. The sequence of snapshots are connected together by animated transitions; it can be previewed in the dialog and saved to a high quality movie format such as MP4 or WMV. Next, you will create a series of snapshots of your 3D view. To create a snapshot of a 3D view: 1. In the 3D view select the Create Snapshot icon ( toolbar in the 3D Viewer.
) from the navigation
The Create Snapshot dialog opens. Figure 5.12 The Create Snapshot dialog
2. Specify the Name as 0.015 Isosurface. 3. Click OK. 4. Repeat these steps twice more, once rotating the 3D view, then turning on the Surface_SRTM World Elevation MGA 90m layer in the map manager. Next, you will manage the snapshots you created in the previous step. To manage snapshots: 1. Right click in the data view and select Manage Snapshots. The Manage Snapshots dialog opens.
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Lesson 5.6 Creating Snapshots and Animations
Figure 5.13 The Manage Snapshots dialog
2. In this dialog, you can reorder, delete and go to the snapshot view. 3. To view in 3D click the View in 3D icon ( and to delete, click the red X.
). To reorder, use the Arrow icons
4. When you are satisfied with your selections, click Close to return to your 3D view. Next, you will create an animation from your 3D snapshots. To create an Animation from your 3D snapshots: 1. In the 3D view select the Create Animation from Snapshots icon ( the navigation toolbar.
) from
The Create Animation from Snapshots dialog opens. Figure 5.14 The Create Animation from Snapshots dialog
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Module 5: Creating a 3D Map 2. Change the Duration (s) of the three snapshots to 1s. You can also change the Transition from one snapshot to the next, as Zoom Out, Spin, Pause and Direct, using the dropdown lists. You can Include each snapshot or not, using the check boxes. 3. Click the Play icon ( ) to preview the animation. 4. Click the Export Movie button to export the animation. The Export Movie dialog opens. Figure 5.15 The Export Movie dialog
5. Enter Mt Palmer as the Name and change the Resolution to 1080p HD 16:9 (1920x 1080). 6. You can click the More button to access the Frame rate and the Custom resolution parameters. We can leave the Frame rate to the default (30 frames per second) and we have already selected our resolution, so we can leave this unchecked. 7. Click the OK button. The movie file will be saved to your project folder.
In this lesson you: Created snapshots from the 3D view Managed your snapshots Created an animation from the snapshots
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Module 6: Wireframing Module 6 has Five Lessons:
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Lesson 6.1 Creating a Geostring File and Adding Features
162
Lesson 6.2 Digitizing Interpretations on Section Maps
166
Lesson 6.3 Editing Geostring Files
169
Lesson 6.4 Wireframing Interpretations
173
Lesson 6.4 Sharing 3D Data
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Lesson 6.1 Creating a Geostring File and Adding Features In this lesson you will: Create a geostring file Add a polygon feature to a geostring file
Explicit Modelling Geological Interpretation and Wireframing Explicit modelling in Oasis montaj enables you to build 3D models from 2D interpretations drawn on section or plan maps. There are four main parts to the modelling workflow: Create a series of horizontal or vertical section maps containing the data to support your interpretation. Digitize two-dimensional (2D) interpretations on section or plan maps. Open the 2D interpretations in the 3D Viewer and wireframe (connect) them together to form 3D volumes and/or surfaces. Use the analysis tools to extract information from the volumes and surfaces. Volumes and surfaces can be used as geological constraints in geophysical inversion, that is the process of producing a 2D or 3D model from geophysical data. A very important factor in geophysical inversion is non-uniqueness: for any observed geophysical response, there are infinite individual geological models that can cause that response. Many of those models are not going to be geologically realistic. Therefore it is very important to use as much geological data as possible to constrain the inversion, that is, keep it within the geologically reasonable range of models. Recall the conductivity sections you have been working with in previous lessons; that data is derived from 2D inversion. If you look at the sections, it is evident in each that there is a sub-horizontal conductivity contrast. This contrast is likely to represent the transition from overlying, conductive regolith into poorly conductive Archean greenstone basement. As the gold in this area is associated with the Archean basement, it is important to know the depth of this transition wherever possible. If you can interpret a 3D volume of the regolith from and between these sections, you could use this volume to revise and better constrain the magnetic susceptibility model that we also have in our 3D view. In this lesson you will use explicit modelling to build a 3D volume of regolith from the conductivity sections.
Geosoft Geostring Files Geosoft geostrings are 3D vector files that store digitized interpretations drawn on section maps. Both polygon and polyline features can be stored in the same file. Geostrings store the following information:
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Lesson 6.1 Creating a Geostring File and Adding Features
XYZ locations Coordinate system Attributes including feature names and symbology The coordinate system for the geostring is automatically set based on the current database. You can use the tools available on the Geostrings toolbar, displayed below the Navigation toolbar in the map window, to create a geostring file, digitize interpretations, manage the geostring and edit the vertices in a geostring file. The toolbar is active when a Geostring is added to a map. The toolbar is displayed within the map window when you create or open an existing geostring from one of the following menus: Map Tools, Section Tools, or DH-Plot menu. Figure 6.1 Geostrings Toolbar displayed on the Mt_Palmer_Conductivity_L1.map
To create a geostring file: 1. Close the 3D Viewer window and Mt Palmer 3D.map. 2. Open Mt Palmer Conductivity_L1.map. (The section map not the profile plot.) Ensure that Mt Palmer Conductivity.gdb is selected. 3. From the Section Tools menu, select New Geostring. The New Geostring for Geological Feature Interpretations dialog opens. Figure 6.2 New Geostring for Geological Feature Interpretations dialog
4. For Output geostring name, enter Mt Palmer Interp. 5. Click the Coordinate System button. The Coordinate System dialog opens.
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Figure 6.3 Coordinate System dialog
The Coordinate system is automatically set to GDA94 / MGA zone 50 based on the projection of the Mt Palmer Conductivity.gdb. 6. We can accept the default projected coordinates. Click OK. To add a polygon feature to a geostring file: 1. To the right of the Features to digitize box, click the Add new feature button ( ). The Add Feature dialog opens. Figure 6.4 Add Feature dialog
2. For Name, enter Regolith. The Digitization type is Polygon by default. 3. Click the Appearance buttons and change the Edge and Fill colours to blue. 4. For Description, enter Uneconomic cover sequence and click Add. The Regolith is added to the list of Features to digitize. 5. Click OK.
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Lesson 6.1 Creating a Geostring File and Adding Features
You can manage your features by clicking the Manage Geostring button ( ) on the Geostrings toolbar. You can also import features from another Geostring file.
In this lesson you: Created a geostring file Added a polygon feature to the geostring file
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Lesson 6.2 Digitizing Interpretations on Section Maps In this lesson you will: Prepare section maps for digitizing Digitize polygon interpretations on section maps
Snapping Snapping can make digitizing more efficient and accurate. If snapping is on when digitizing an interpretation on a section map, a red circle will appear around the tip of the cursor when it comes within 10x10 pixels of the specified Snap To item. The following table describes the three snapping options and their snapping circle colours: Table 6.1 Snapping Options
Snapping Circle Colour
Snap To Option
Description
True Drillhole Locations
The cursor will snap to the true X, Y, Z location along the drillhole trace from the interval or point in the specified drillhole database.
Pink
Projected Map Groups
The cursor will snap to the X, Y, Z location of the specified map group projected onto the centre plane of the section.
Red
Geostring Features
The cursor will snap to the X, Y, Z location of the specified geostring feature. Polygon and polyline features can snap to other polygon and polyline features including to polygons and polylines of the same feature.
Orange when snapping to a vertex; Red when snapping to an edge
To prepare section maps for digitizing 1. Open the three "Mt Palmer" conductivity section maps created earlier. Size the maps so that you can see the section grids as clearly as possible. 2. Select Mt_Palmer_Conductivity_L1.map. 3. Go to the Map Tools menu, select Contour and then Contour. 4. For the Input grid file, browse to the Geosoft Training Data folder and load L1_ IDW.grd. 5. For the Contouring option, choose exact levels. 6. For the (smallest) Interval Level 1, enter a value of 10. 7. Click on the Line Styles button.
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Lesson 6.2 Digitizing Interpretations on Section Maps 8. For the Line weight-colour level 1, select thick-black. 9. Click Back and then OK. 10. Repeat steps 2-9 for MtPalmer_Conductivity_L2.map and MtPalmer_ Conductivity_L5.map, making sure to use the appropriate section grid for each map. 11. Go to the Settings menu, select Map Settings and then Snap Grid Resolution. 12. Set the resolution to 1 mm and click OK. To digitize geological polygon features on a section map: 1. In the Project Explorer, ensure that the Maps tree is expanded. 2. Double-click Mt Palmer_Conductivity_L1.map to make it the current map. 3. From the Feature list on the Geostrings toolbar, select Regolith. 4. Click Digitize Interpretations (
) on the Geostrings toolbar.
5. Click the Toggle Snapping button. 6. From the Snap To list, select CONTOUR_L1_IDW in the Projected Map Groups section. When you hover the digitization cursor over the contour on the section map, observe how it changes. If you allow the cursor to rest for a moment, you will see the following information reported in a tooltip: The map group the cursor is snapping to The X, Y, Z position (along the centre plan of the section) 7. Digitize a polygon for the regolith layer. Start by digitizing (and snapping to) the contour. When you need to digitize along the topography, choose Topography from the Snap To dropdown. 8. To close the polygon, right-click and select Done. Figure 6.5 Regolith polygon interpretation on Mt_Palmer_Conductivity_L1.map
9. Repeat this process digitizing a regolith polygon on the following section maps: Mt_Palmer_Conductivity_L2.map Mt_Palmer_Conductivity_L5.map
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If you recreate a section map or replot the holes on a section map, the interpretations in the geostring file will remain visible on the map.
In this lesson you: Prepared section maps for digitizing Digitized polygon interpretations on section maps
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Lesson 6.3 Editing Geostring Files
Lesson 6.3 Editing Geostring Files In this lesson you will: Change the colour of a feature in a geostring Add a feature to a geostring Digitize a polyline interpretation Delete an interpretation from a section map Delete a feature from a geostring View a summary of the interpretations on section maps View the interpretations in the 3D Viewer
Editing Geostring Features The Manage Geostring and Interpretations Properties tools on the Geostrings Toolbar enables you to edit your geostring file and all its associated features and interpretations. Using these tools, you can add and delete features, or change the properties of an interpretation after it has been digitized. In the Manage Geostring tool, you can also import features from another geostring that were digitized on the same drillhole project, by another user or in another workspace. To change the colour of a feature: 1. On the Geostrings toobar, click Manage Geostring. The Manage Geostring dialog opens. 2. Select Regolith and click the Edit selected feature button ( The Edit Feature dialog appears.
).
3. Click inside the Fill colour box and select red from the Colour palette. 4. Click OK on the Colour palette. 5. Click inside the Edge colour box and select red from the Colour palette. 6. Click OK on the Colour palette. 7. In the Edit Feature dialog, click Save. 8. In the Manage Geostring dialog, click OK. The colour of the Regolith feature automatically updates on the section maps. Next, you will add a new feature to the geostring. To add another feature to the Geostring file: 1. On the Geostrings toolbar, click Manage Geostring. 2. Click the Add new feature button. The Add Feature dialog opens. 3. For Name, type temp. 4. For Digitization type, select Polyline. 5. Change the Colour to blue.
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Module 6: Wireframing 6. Click Add. 7. Click OK. Next, you will digitize a polyline interpretation on Mt_PalmerConductivity_L1.map. To digitize a polyline on a section map: 1. Activate the Mt_Palmer_Conductivity_L1.map to open it in the Data View. 2. On the Geostring toolbar, click the Digitize Interpretations button (
).
3. From the Current Features dropdown list, select temp. 4. Digitize a polyline line along the base of the section grid for the length of the section. 5. To end the polyline, right-click and select Done. Figure 6.6 Mt_Palmer_Conductivity_L1.map showing polyline and polygon features of the geostring
Next, you will delete the polyline that you digitized on the section map. To delete an interpretation: 1. On the Geostrings toolbar, click Interpretations 2. Click to select the blue "temp" polyline interpretation. Once selected it will be bounded by a cyan border. 3. On the Geostrings toolbar, click the Delete Selected Interpretation(s) button ( ). You can select multiple interpretations by holding the Control key on your keyboard. Next, you will delete the temp feature from the geodatabase. To delete a feature from a Geostring file: 1. On the Geostrings toolbar, click Manage Geostring (
).
2. From the Features to digitize list, select temp. 3. Click the Delete selected feature button (
), then Yes.
4. Click OK. The "temp" feature will be deleted from the Geostring file.
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Lesson 6.3 Editing Geostring Files
It is not necessary to delete interpretations from a feature before deleting the feature. This was only done so you would learn how to perform both tasks. Next, you will view the Geostring Table to see a summary of the digitized interpretations on each section map. To view the Geostring Table: 1. On the Geostrings toolbar, click the Geostring Table button ( The Geostring table appears.
).
Figure 6.7 Geostring table for Mt Palmer Interp.geosoft_string
2. Click Close. After selecting a section map, you can click the Delete button to delete all the interpretations for the selected section. All the interpretations for all the features are deleted from the geostring and this action cannot be undone. If you see a row in the table highlighted in pink, this indicates that the section map cannot be found because it was either moved or renamed. Select the row and click the Find Missing Map button to browse and select the missing map. You will now view the interpreted geostring file in the 3D Viewer. To view the geostring in the 3D Viewer: The 3D Viewer opens displaying the Mt Palmer 3D 3D view. 1. In the 3D Tools, turn off all the displayed planes and surfaces and 3D objects. 2. From the Add to 3D menu, select Geostring. 3. For Geostring File, browse and select Mt Palmer Interp.geosoft_string and click OK. Your section interpretations are displayed in the 3D Viewer.
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Figure 6.8 3D Viewer with Mt Palmer Interp geostring
In the 3D Manager, the geostring file is listed as the top node under 3D Objects. Within the geostring item, the sections that have interpretations for the feature are listed. Figure 6.9 Geostring in 3D Viewer tree list
You can turn off the visualisation for some of the other map groups to help you see the geostring file more clearly. Viewing the geostring alongside other data may help indicate which interpretations require editing. Changes to interpretations are done on the section map and the geostring will automatically update in the 3D Viewer.
In this lesson you: Changed the colour of a feature in a geostring Added a feature to a geostring Digitized a polyline interpretation Deleted an interpretation from a section map Deleted a feature from a geostring Viewed a summary of the interpretations on section maps Viewed the geostring in the 3D Viewer
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Lesson 6.4 Wireframing Interpretations
Lesson 6.4 Wireframing Interpretations In this lesson you will: Start a wireframing session Join polygons to form a closed surface wireframe Add ends to a closed surface Save a surface to a geosurface file View the total surface area and total volume for a surface
Wireframing Wireframing is the process of joining 2D interpretations to form 3D surfaces. In Oasis montaj, this process is streamlined, efficient, and intuitive. After starting a wireframing session, you click interpretations in the 3D Viewer to form the wireframe. All the required tools are found in the Wireframing Tools panel that displays when a wireframing session is in progress.
Geosurfaces Geosurfaces are 3D vector files that store the results of wireframing or isosurface creation. The files can be saved and shared with others, and also used in voxel math expressions and VOXI constraint building. Geosurfaces store the following information: XYZ locations Coordinate system Attributes including feature names and colours The coordinate system for the geosurface is automatically set based on the geostring used to create the wireframe. Isosurfaces, created from a voxel, are also stored in geosurface files. To start a wireframing session: 1. From the Wireframe menu, select Start Wireframing. The Start Wireframing dialog opens. Figure 6.10 Start Wireframing dialog
2. The Geostring to wireframe field should contain the Mt Palmer Interp that you have just loaded into the 3D View. If not, click Browse and load the appropriate Geostring.
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Module 6: Wireframing 3. For Feature to wireframe, select Regolith. 4. Click OK. The Wireframing Tools are displayed on the right side of the 3D Viewer; note that you are in Wireframing Mode. The regolith interpretation polygons are bounded in yellow. Figure 6.11 3D Viewer with Wireframing Tools displayed
To create a closed surface by wireframing polygons: 1. The Geostring to wireframe field should contain the Mt Palmer Interp that you have just loaded into the 3D View. If not, click Browse and load the appropriate Geostring. 2. For Feature to wireframe, select Regolith. 3. Click OK. 4. In the 3D Viewer, click to select the closest polygon to you in the 3D view. The selected polygon is bounded by a cyan border. 5. Click the adjacent polygon. You now have the beginning of a wireframe body. Both ends are bounded in cyan meaning you could continue adding to the wireframe from either side. 6. Select the remaining polygon to add it to the wireframe body. If you have interpretations that belong to the same active feature that need to be treated as separate wireframes, click the Add New Wireframe Body button. For instance, the same rock type may occur in two separate areas (separated by a fault) or may bifurcate. 7. To add ends to close the wireframe body, click the Create Wireframe Ends button (
) on the Wireframing Tools panel.
8. Choose Conical, accept the default settings and click on both ends to close the body. Both ends are now closed off.
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Lesson 6.4 Wireframing Interpretations
To save the volume to a Geosurface file: 1. When you are finished, click on the Save Wireframes as Geosurface File located within the Wireframing pane. 2. Select the Palmer Geosfurface file and click OK. The Wirefaming session closes and the Regolith feature is appended to the Palmer Geosurface file in the 3D View, which now displays both features. Figure 6.12 Wireframed body with closed ends in 3D Viewer
While wireframing, you can use the Undo/Redo buttons on the Wireframing Tools panel or use the Ctrl+Z and Ctrl+Y shortcut keys, respectively. To save the wireframes to a geosurface file: 1. On the Wireframing Tools panel, click the Save Wireframes as Geosurface File button (
).
2. For File name, enter Mt Palmer Regolith and click Save. The surface Regolith is added to the 3D Objects tree. Figure 6.13 Mt Palmer Regolith geosurface in 3D Viewer tree list
To view the Total Surface Area and Total Volume for the Regolith surface: 1. In the 3D Objects tree, select the Regolith object under SURF_Mt Palmer Regolith . 2. Click Properties in the Attributes tab. The Geosurface Properties dialog opens.
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Module 6: Wireframing Information about this surface, including Total Surface Area ("Area") and Total Volume ("Volume") are displayed. 3. Click Close.
In this lesson you: Started a wireframing session Joined polygons to form a closed surface wireframe Added ends to a closed surface Saved a surface to a geosurface file Viewed the total surface area and total volume for a surface
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Lesson 6.5 Sharing 3D Data
Lesson 6.5 Sharing 3D Data In this lesson you will: Export a Geosurface to a DXF Export a 3D View to a 3DV file
Sharing Data from a 3D View, the 3DV File Exporting a 3D View as a 3DV file creates a *.geosoft_3dv file which is a package of all the data that is listed in the 3D Viewer tree. The display options (i.e. zoom, rotation, which layers are turned on/off, transparency, colours, etc.) are also written to the 3DV file. This is an easy way to create a single file for all the data in the 3D View so you can move the View and datasets to another folder, or to share the View and data with a colleague to collaborate on a 3D project. Vector datasets in the 3D view (such as Geosurfaces) can be exported to an AutoCAD 3D DXF file, which is an almost universally recognized file format within our and other 3D capable geoscientific software. In this lesson we will first export the Mt Palmer Regolith Geosurface to a 3D DXF file. We will then export the entire 3D view to a 3DV file. To export a Geosurface to a DXF: 1. From the Export menu in the 3D Viewer, select AutoCAD DXF File. The Select Map Groups to Export dialog opens. 2. Select SURF_Mt Palmer Regolith from the Not Selected column. Use the single arrow button to move it into the Selected column and click OK. 3. Accept the default file name for the output DXF. 4. Click OK. The DXF is added to the project folder. To export a 3D View to a 3DV file: 1. From the Export menu in the 3D Viewer, select Geosoft 3DV File. The Export 3D View to Geosoft 3DV File dialog opens 2. For Output 3DV name, enter Mt Palmer. 3. Click OK. The Mt Palmer.geosoft_3dv file is added to the project folder. You can import this file into any other Geosoft project that is saved, in any location. From the 3D menu, simply select Imports and then Import Geosoft 3DV file. This will extract the packed contents (voxels, girds, geostrings, geosurfaces) to the folder where the project is saved.
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In this lesson you: Exported a Geosurface to a DXF Exported a 3D View to a 3DV file
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