Vellum,

My first response, "Because I could." Actually, haven't spent the time to learn Gimp or Inkscape. Have a RPG city that needed fleshed out as a rough draft.
Excel on work and home systems, so was able to work on it anywhere and in bitesize time increments. I have a new version to post, but found an interesting way to use lines to creat a cobblestone appearance on roads.