Extensions are add-on programs that provide advanced geographic information system (GIS) functionality. When you load an extension, ArcView's user interface changes to reflect the functionality in the extension. New menus, menu items, buttons, and tools may appear, and new options may be available in existing dialogs.
If you have your own copy of ArcView, this extensions dialog can be accessed by choosing the Extensions option from the File menu when the Project Window is active. While in the Project Window, you can load and unload extensions at any time during an ArcView session.
ArcView allows you to load different extensions for different projects or make your extension choice(s) the default for ArcView. Keep in mind that the more extensions you load, the slower ArcView will run. Therefore, you may only want to load the extensions that are being used in your project rather than loading them all at once.
ERDAS IMAGINE is an image processing software program that is used for image mapping and visualization, image processing and advanced remote sensing. The IMAGINE Image Extension allows you to integrate remotely sensed images with your GIS vector layers by directly reading ERDAS IMAGINE .img files into ArcView views and layouts. If you open a project that uses an extension that is not currently loaded, ArcView will automatically load the extension for you. If you are not using the ArcView project file provided on this CD-ROM, follow the steps below to load the IMAGINE extension manually.
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To load the extension, go to the Project Window and click File/Extensions. This gives you a dialog box that allows you to choose which extensions you would like to load. Choose the IMAGINE Image Support extension by checking the box next to it. Click OK. |
Alternatively, open the ArcView project file containing the extension, go to the Project Window, click File/Open project, and choose the file landcov.apr. The project may take a minute or two to load. Read and close the introductory page and then only the landcov.apr project window will be open. This window shows a list of the thematic views available in the project. Select the Tutorial View and click the Open button at the top of the list. This window may be moved and resized to make use of the full screen.
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Next, click the Add Theme  button
and navigate to the d:/data/jasp directory on your CD-ROM drive. Choose Image Data Source as your Data Source Type. Here you will find an .img file named jasp90.img. This is the 1990 land cover classification of Jasper County in State Plane projection. Add this to your view by clicking on the file then clicking OK. |
Click the Add Theme button again. Using the same data directory, change the Data Source Type to Feature Data Source. This allows you to see the shapefiles (ArcView's preferred file type). Click on the file named st_jasp.shp to add the major streets theme to your view. Turn the themes on by checking the gray boxes next to the theme names.
The roads vector layer is now overlain on the image. Try using the zoomin 
and zoomout 
buttons to explore the data.
This extension was created for users to import LIDAR beach mapping data sets directly into ArcView. LIDAR beach mapping data are composed of elevation measurements of the beach surface and were acquired during aerial topographic surveys. The file format used to capture the LIDAR data is referred to as "x, y, z", where x is longitude, y is latitude, and z is elevation. This extension automatically loads the "x,y,z" points into a table and displays them as a shapefile.
Before you begin this tutorial, you will need to have acquired a LIDAR data set. These data sets can be extracted from the BeachMapper software application provided on volume 2 of this CD-ROM set, or by the web-based LIDAR Data Retrieval Tool (LDART). For more information about the BeachMapper application, click here. To use LDART, click here.
To load the LIDAR Loader extension into your project file, you must first move this extension (lid_load.avx) from the d:/exten folder on volume 1 of this CD-ROM set into the Environmental Systems Research Institute (ESRI®) extension folder on your computer's hard drive. The path for the ESRI extension folder is shown below.
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To load the extension, open ArcView or your project file, go to the Project Window and select Extensions from the File menu. This gives you a dialog box that allows you to choose which extensions you would like to load. Choose Lidar Loader Extension by checking the box next to it. Click OK. |
Open a new View, and you will see that the Bex the Dog button 
has been added to the standard set of icons along the top row. Click this button
and you will be prompted to search for the LIDAR data file you created. Shortly, you will
be prompted for an output name and location. This will be the ArcView shapefile version of the
text file you created with BeachMapper or LDART.
A note of caution: Depending on your computer system specifications (e.g., processor, disk space, amount of RAM), it may take quite a long time to process large LIDAR BeachMapper data sets in ArcView. To ensure you will not overload the processing capability of your computer, check the file size of the LIDAR Beach Mapping data text file you download. A data set no larger than 1 megabyte is recommended for this test of your system.
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This is all you have to do. The extension will load your text file as a table, add it as a new Theme to your View, classify the "x,y,z" points by the elevation in a simple green colormap, and save the point data to the shapefile you named. You can edit the colormap by clicking on the legend for the point theme. For more information about editing the legend, click here. |
For information on making contours with this theme, click here.
Listed below are a few of the built-in extensions that come with ArcView 3.0.
MrSID® ArcView Extension
MrSID is an image compressing software package that retains all spatial information and allows faster drawing time. The MrSID ArcView extension allows users to view MrSID compressed images in ArcView. This extension is provided with ArcView V. 3.1 software.
Database Themes extension
The Database Themes extension provides multi-user, client-server access to data managed by ESRI's Spatial Database
Engine (SDE). The Database Themes extension is not available on the Macintosh, Windows 3.1, or Windows for Workgroups.
Digitizer extension
The Digitizer extension provides support for digitizing tablets. You can use a digitizing tablet to create and edit
shapefiles, and as your general input device for using ArcView (instead of a mouse). The Digitizer extension is not
available for UNIX or the Macintosh operating systems.
CAD Reader extension
The existing CAD drawing support in ArcView V. 2.1 is now implemented as an extension in ArcView V. 3.0.
Support has been added for MicroStation® DGN files, AutoCAD® Release 13 drawings, and binary DXF files.
JPEG Image extension
JPEGs are a common file format for images and were previously not accessible in ArcView. The JPEG Image extension
allows you to add .jpg files to views and layouts.
In addition to the pre-loaded extensions listed above, ArcView also provides several other useful extensions, including the
Projection extension. These extensions have an .avx suffix and are located in the following directory structure:
ESRI/Av_gis30/Arcview/Samples/ext.
To make these extensions available, simply copy them from the ESRI/Av_gis30/Arcview/Samples/ext as shown in the image below and paste them into the ESRI/Av_gis30/Arcview/ext32 folder. For additional help and information, look up extensions in the ArcView help files.
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