Anyone know of maps of ancient and medieval Rome?

It’s amazing how many maps of historical phenomenon that there aren’t. I’ve been trying to track down maps of ancient and medieval Rome at different points in the city’s history. I can find plenty of Rome with the Servian walls around it – these were supposedly built by the second-to-last king of Rome, Servius Tullius, in the 6th century BC, but were almost certainly not built until the mid-4th century BC, probably in the wake of the Gallic attack on Rome in c. 390 BC. Then I can find one with the Aurelian walls – these were built on the orders of the emperor Aurelian (reigned 270-275 AD). But finding maps of early Rome, or of Rome at the time of Augustus, or of Rome in the early Middle Ages, is very hard.

The nearest I have come to one is at a really good site by the University of Virginia – http://www3.iath.virginia.edu/waters/timeline/ . It’s an interactive map of ancient Rome’s water supply, with the dates for the aqueducts, baths, fountains, wells etc. If one studied this in detail, and combined it with other maps and data, one could probably arrive at a rounded picture of the development of the city of Rome. However, surely such work has already been done – can anyone help me?