"Subway map" style ancient Roman road map
The map at the following link presents an interesting style. It make no attempt to be geographically accurate. What it does is present the Roman road network in Europe in a manner that makes it easy for a commander on the march to establish best routes and determine how many days it will take. This paricular map is a 1624 replica of Roman map that is much older.
Many scans here:
It's an interestigng approach I hadn't thought about using. It also has some nice style effects.