Description:

The atmospheric correction extension is an extension to ArcView designed to accomplish a relative atmospheric correction on a multi-temporal set of Landsat Multi Spectral Scanner (MSS) and/or Thematic Mapper (TM) satellite imagery. The extension is designed to follow a three step iterative process which includes conversion of "raw" Digital Number (DN) ERDAS Imagine images to at-satellite (also known as exoatmospheric) reflectance or radiance, calculation of the Soil Brightness Index (SBI) and Green Vegetation Index (GVI) using the "Tasseled Cap" transformation, and relative atmospheric correction using Pseudo Invariant Features (PIFs). The extension also includes programs that allow the user to set environment variables for choosing the number of Pseudo Invariant Features (PIFs) and calculation of Vegetation Indices (VIs).

Three general environment variables of note include the $AVEXT and $USEREXT variables for arcview extension management, and the working directory for file management. $AVEXT represents the directory that contains arcview extensions. This directory may be write protected, especially if you are sharing your ArcView license over a network. In order to give any user flexability to add/delete extensions to suit their needs, ESRI has set up a second environment variable that arcview accesses for user extensions. This directory is represented by the environment variable called $USEREXT. If this variable is not set, you should do so. Commands for setting these variables will depend on the platform you are working from (Windows/NT or Unix). Basically, you will have to add a line that looks something like "SET USEREXT=C:\tvn\ext" in your autoexec.bat file for Windows/NT or "setenv USEREXT /auto/tvn/ext" in your .cshrc file for Unix systems. The project's working directory defaults to $HOME. You can change the working directory for your project either through the project's property dialog box or through the Set Working Directory choice in the View document user interface File menu. From Avenue, you can change the project's working directory with the request SetWorkDir (ESRI Help).

The $USEREXT directory is where you should download the atmospheric correction extension. This is where you should also save the table called "exoat.dbf", your help program ("hh.exe" & "hh.dat"), and your help file ("atmos.chm").

The atmospheric correction extension depends on both the "Imagine Image Support" (IIS) and "Spatial Analyst" (SA) extensions. It is assumed, then that both of these extensions are loaded prior to loading the "Atmospheric Correction" (AC) extension. IIS and SA, then, are Dependancies. If you load all three extension at the same time, the IIS and SA extensions will not load properly and the AC will not run. If this is done, you will not be able to uninstall the IIS and SA extensions after unloading AC. Please see ON-LINE HELP files for more details.
Download ATMOS EXTENSION Version 2.1 (right click and choose "Save Target As...")

Description:

This table contains information needed during the exoatmospheric correction step. This table must be stored in your $USEREXT directory before loading the Atmospheric Correction Extension or added manually to your ArcView project when running the scripts separately. Please see on-line help for details.
Download EXOAT TABLE (right click and choose "Save Target As...")
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