Stanford has just launched Orbis, a self described: “Geospatial Network Model of the Roman World reconstructs the time cost and financial expense associated with a wide range of different types of travel in antiquity.”
Scholars, laymen, educators, and students can use this tool to made traveling networks (by land and sea) for more than 751 ancient sites in the ancient world and are able to examine mileage distance, travel difficulty, and estimated time for traveling by foot or boat.
This is an amazing and innovative tool for those working in the ancient world. It is easy to navigate and quick to adapt. I highly recommend playing around – try to figure out how long it would take to get from Londinium to Antioch as a civilian or a soldier, by land or by sea.