I'm not sure how to go about this, so I'm asking the experts for their opinion. How would one go about mapping an actual location? In this case, let's say the Mediterranean Sea at some point during the Roman Republic.

Google Earth and other satellite images will allow one to see the shape of everything, however the problem comes when creating the actual coastline as difference clouds + threshold = randomness. I suppose since my goal is to make the map look like it dates from Roman times, accuracy is not paramount, however getting the general shape is important. Not to mention that everything is in the proper place in relative to other parts of the map, i.e. the Italian Peninsula can't look incredibly long while Greece looks squat, if you get my point.

Any thoughts? I don't think I've encountered any real-world maps on here yet.