1.4.2.1. External DEM Selection



Help for External DEM Selection

With this function you can choose the source of your External DEM

The default external DEM is SRTM (see notes)

To manually choose SRTM, press the button "Reset"

Otherwise, have 2 options:

a) loading a GEOTIFF file. Do this via "Choose file" and select the corresponding tif file
If the file is correctly identified and read, all parameters are automatically filled.

b) loading a matrix, described by the parameters visible in the window. Currently, the matrix must
be organized as a DEM file produced by Gamma. If a Gamma parameter file is available, it can be
imported via the button "Import par", and all parameters are automatically loaded

In the Gamma format, the matrix is organized as follows:
columns are Latitudes, rows are Longitudes, the file is float, big endian

Conversion between Geoidal and Ellipsoidal Height: work in progress


Notes:

The tool automatically downloads SRTM files from internet

If anything fails, a message is printed but the tool
does not stop running

If a SRTM file is not found, it is created and filled with zeros

To re-download a file that was filled with zeros, delete it (the software will warn you if a
file filled with zeros is found)

SRTM files can be manually placed in DirSite/../SRTM