I’ve also uploaded a script I wrote called get_quad.py, which will download USGS topographic maps automatically. This script naturally complements gdal_slice.py; using the two together allows for almost-totally automatic population of GPSdrive’s map database with high quality topographic maps.
usage: get_quad.py [-h] [-q] [-s STATE] (-g | -c COORD COORD)
Get DRG USGS quad for given latitude and longitude from LibreMaps.org
optional arguments: -h, --help show this help message and exit -q, --silent don't produce any output -s STATE, --state STATE Postal abbr. for the state in which the quad falls, so we don't need to look it up -g, --gps get coordinates from GPSd -c COORD COORD, --coords COORD COORD specify latitude N and longitude E (respectively) in decimal degrees; longitude should be negative, as all maps fall in the western hemisphere
Unfortunately, because of the way USGS maps are organized, the script needs to know the state in which the coordinates fall. If the -s flag is not given, this is inferred from the coordinates, but this lookup requires internet access.