A shared repository for CAD/CAE graph transformations
Download all hgt files for Poland (this will take a while, but can be safely interrupted).
$ wget -r -nc -nH --accept-regex='.*N[1-5][0-9]E0[2-5][0-9].*' https://dds.cr.usgs.gov/srtm/version2_1/SRTM3/Eurasia/
Compile https://github.com/Podsiadlo/terrain using
cmake . && make
Run
tergen -o out -Y -d Data/SRTM3 -x 3000 -y 3000 -z 3000 -i 1 -j 1 -k 1 -N 54.5 -S 49 -E 14.07 -W 24.09
to get terrain data for poland