What goes on your map is what's important for the purpose of the map and little to nothing else. Decide on why you're making this map and what's important or unimportant should become clear. For example, is this a historical map done during the height of the civilization to show the location of the royal cities or a recent map showing what's been lost? Who is the audience of the map? For example, a map showing the grandeur of the empire might have a slightly different slant than a civil works map highlighting irrigation systems and a military map showing defensible lines and fortifications will be different still.