first of all, I'm not looking for an automatic conversion tool.

I got bitmap maps of a fantasy world and I would like to have a lat/lon file of coast/ rivers/ etc. (the bitmap has lat/lon grids).

my first idea was to use the bitmap as a background image in a vector program (inkscape? DrawPlus?), draw vectors along the requested parts (coast, rivers, etc.), then convert the resulting vectors into lat/lon (ie. CSV file). but well, I'm a bit lazy and would prefer not to have to write the SVG to latlon program and was wondering if any of you had a better idea to solve my problem ?

TIA, Pyer