I recently completed a city map for use in a Spelljammer short campaign I'm running with my gaming group. I had already created both a Spelljamming ship and a small scout ship based around the corpses of gigantic beetles and posted deckplans for both in the Finished Maps forum. Working on the background for those ship designs, I came up with an ancient Egyptian theme, with a race of advanced gnolls called Gnolleans who worship Anubis (since Anubis is a jackal headed humanoid in one form, and gnolls are hyena-headed humanoids, the relationship seemed natural.)
Since Anubis is intrinsic to this culture over the other deities worshipped, and because Anubis is the guardian of the underworld and the dead, (and Duat is the Egyptian word for the Underworld), I opted to call this the city of Duat.
In order to be fairly accurate in a representation of ancient Egypt, I began a quick study on ancient Egyptian architecture based on archaeological sites. What I actually did was hodge-podge an Egyptian capital city combining the Temple of Amun and other temples at Karnak, the Tomb of Nefretiti in the Valley of Kings, the smaller pyramid at Giza, artist renditions of the Libary of Alexandria into a single location.
First I created the central pyramid, included the wall and temple block that was near the original (but reduced to rubble in the present), added a Sphinx statue of the earliest Anubis statues (not in humanoid form, but sitting like a jackal and a sphinx). I determined that the religious center was the center of the city, and the area should include all the bulidings of state, the residences of the pharaoh and the nobility. Once that concept was down buliding a massive city around that became the essence of the design. Also many ancient fortifications are square or rectangular in design, something I've never designed a city to resemble, so decided that's what I'd do here.
Of the non-state precincts of the city, as the central part of the Slave Quarter (the eastern third of the city) and the Artisans Quarter (northwest corner) and Merchants Quarter (southwest of corner), since there are no ancient Egyptian ruins of towns and households (none have survived as ruins), I had to make that up, so I based their design on the City of Shibam in modern Yemen. It looks middle eastern, so I worked with that - and why those quarters are so sloppy in layout.
Here is the WIP thread I posted while creating this city map.
I created this entirely using Xara Photo & Graphic Designer 9, a vector drawing application. Though I often incorporate 3D elements in my maps, I did not do so in this example. As always, I use photorealistic images as object fills, many of those textures from CGTextures.com (a great source of free photo textures).
I am currently creating a detailed gazetteer of important locations in the City of Duat, of 32 places, and considering releasing this as a Gamer Printshop map product. I may even include a write up of my Gnollean race, their history, the development of its empire and its association with Spelljammer, at the same time include that this could be easily used in a non-Spelljammer campaign that needs elements of ancient Egypt - mummies, pharaohs, pyramids, all common to many D&D settings and other games - and sell it through DrivethruRPG.com where I sell my other map products.