Sorry, I guess I wasn't quite clear with my question. With a "hexmap" I mean a map that is based on a hexgrid, not a regular map that simply has hexes overlain. Coastlines, rivers, roads, borders etc should still be freehand. Basically looking for a hexcrawl type thing.

The problem isn't that it's impossible to do with Gimp/Inkscape (I can't afford Adobe products I fear), but rather that it's exceedingly tedious. Gotta place those hex symbols absolutely correctly or it'll look crappy. The usual .svg hex grid generators do centerdots, so it can be done, but... it's just... a lot of really fiddly work anyway.