Version 7 (modified by dac, 21 months ago) (diff)

Added gdalwarp command

Q: What format should my DEM be in when using aplcorr?

APL expects the Digital Elevation Model (DEM) to be in a 1-band ENVI BIL or BSQ file format. This is a simple binary format where the data is stored as a string of binary information with an accompanying header file that describes the number of bands / lines / samples. Further information on this file format can be found in the ENVI tutorial:

The elevation data should be projected in WGS84 Latitude and Longitude with heights referenced to the WGS84 spheroid. If possible a Digital Surface Model (DSM), providing the top of canopy / building height is preferred.

For preparing a DEM for use in APL the ARSF DEM scripts (available to download from can be used. For more details on usage see the tutorial.

You can convert an existing DEM (providing the heights are referenced to the WGS84 spheroid) using GDAL, for example:

gdalwarp -t_srs EPSG:4326 -of ENVI in_dem_utm.tif out_dem.dem