Creating a DEM index file

The DEM Index File Creator module preprocesses and creates the required index file for orthorectification based on a series of tiled DEM files. You must run the DEM Index File Creator module before you ingest your data if you are using a tiled-DEM folder as a DEM source.

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 of the other tiles.

After extracting the tile information, the DEM Index File Creator module opens each tile in the DEM folder in sequence, comparing the information with the reference tile. If any of the details do not match the reference tile, the module rejects the file as a "bad" tile , and then writes a warning to the log file.

After examining all of the tiles, the DEM Index File Creator module creates a DEM index file (index.txt) and a PCIDSK file (index.pix). These files list all of the valid DEM files in the source folder that can be used for DEM processing, and provide information about each one. The generated index files are used as input in the DEM Source parameter in other CATALYST Enterprise modules, such as the Tie-Point Collection and Refinement module.

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

Note: It is important that all the information in the DEM Index file is correct. To confirm that the information is correct, open the first DEM tile in CATALYST Professional Focus and ensure that the DEM covers the entire area for your project, and ensure that the projection and other information is correct. If it is not, open the DEM index file in a text editor, and then manually edit the DEM information, including correcting any bad tiles. Regenerate the index file by rerunning the DEM Index File Creator module.

For more information, see: