Creating a DEM index file

You use the DEM Index File Creator module to create the required index file for orthorectification based on a series of tiled DEM files. This module must be run early in the workflow, because other CATALYST Enterprise modules require an existing index file.

When you run the DEM Index File Creator module, the module opens the first DEM tile in the specified DEM folder (for example, tile1.pix) and extracts information about the tile, including the data type, projection, pixel resolution, and grid alignment. The module then uses this first tile as a reference for all other tiles.

Next, the module opens all other tiles in the DEM folder in sequence, comparing the information against the reference tile. If any of the details do not match the reference tile, the module rejects the file as a "bad" tile and logs a warning.

After all of the tiles have been examined, the DEM Index File Creator module creates a DEM index file (index.txt) and a PCIDSK file (index.pix). These files list all the valid DEM files in the source folder that can be used for DEM processing, and provide information on each. Various CATALYST Enterprise modules use these index files as the value of the DEM Source parameter.

The index files are created in the same folder as the input DEMs.

Important: All of the information in the DEM index file must be correct. In CATALYST Professional Focus, open the first DEM tile and ensure that the DEM covers the entire area of your project. Also ensure that the projection and other information is correct. Correct any errors by editing the DEM index file in a text editor, such as Notepad. Correct bad tiles and regenerate the index file by rerunning the DEM Index File Creator module.

For more information about the module parameters, see the DEM Index File Creator module.

For an example of the format of a DEM index file, see the Format of the DEM index file.