Good maps of Marrakesh are hard to find, especially if you want an accurate representation of the Medina and in particular the souk area.

On line, Google Maps is pretty much useless in the Medina. Open Street Map is somewhat better, but still not great.

Of printed maps, the tear-proof 2010 Rough Guide map of Marrakesh and Essaouira, though out of print and a bit out of date, was the best, and may be available second-hand on Amazon or elsewhere. The 2005 edition, not quite as good, may be cheaper. These are the only maps which cover the souk area accurately.

Failing that, the Villes en Couleurs Marrakesh and Essaouira map (available on line from Éditions Laure Kane) is a reasonable fall-back. Locally, Marrakech Evasions or Marrakech My Map, produced by Bab Sabaa Publishing, and available at some riads and hotels and from some tourist shops around the Jemaa el Fna (try the one by the Grand Balcon du Café Glacier), is better than nothing.