Hi Frank, so these are the steps I used on my ubuntu machine: 1. Download the Copernicus Data and unzip 2. create the virtual tif-image gdalbuildvrt all.vrt *.TIF 3. cut the 1°x1° tiles with the perl script this results in almost 65GB of uncompressed tif tiles 4. convert every tif-tile to hgt using the following loop for i in N*.tif ; do gdal_translate -strict -q -eco -of SRTMHGT $i hgt/`basename $i tif`hgt ; done ; rm -f *.hgt.aux.xml ; 5. I found out that the file N27W000.hgt is completely empty, so all tiles with the identical content are empty also. with the following commands I removed the empty tiles mv N27W000.hgt EMPTY.hgt; for i in N*.hgt ; do if diff EMPTY.hgt $i ; then rm -f $i; fi done ; rm -F EMPTY.hgt; Now I got 25GB in 1001 hgt tiles -- Sent from: http://gis.19327.n8.nabble.com/Mkgmap-Development-f5324443.html