It's fun to steal real city maps and turn them into fantasy cities.
And those look like good examples. I did this with a map of London as well, circa 1600. I didn't have photoshop or anything similar at the time, so I actually printed it out, made a hand-drawn copy (onion paper and all that) which I then photocopied. I used the photocopies for various purposes, such as player maps and the like. It actually turned out really well.