Mapping Ferries, Circles, Curves

I'm building contemporary subway-style maps of historic railway networks and updating everyone on the progress. You can buy or preorder here.

Diagrammatic transit maps, like the ones I’m building, have two primary principles: even stop spacing and clear, straight lines. There’s a lot more to it, of course, as the Transit Maps blog makes abundantly clear, but those are the basics.

Ferry lines throw one of these – straight lines – clear out the window.

The differences between the straight and curvy ferry lines are quite apparent.

When I first started to draft the DC/Baltimore map, I wanted to make sure the ferry lines were included but that they would be straight, dammit. This looked great on the great white vastness of a blank canvass. It looked less great when I started adding water. Suddenly, the ferries were travelling along the beach, or the docks were in the middle of the river. It was ugly and flew in the face of what we intuitively know about how ships work.

But I didn’t want to make the same mistakes as the Sydney ferry map, and the St. Petersburg map didn’t work with my stop symbology. I wanted to show the stop circles halfway on land, halfway off, with the ferry line easily sliding behind as it wound its way back to Baltimore.

This meant curves, and that meant circles, and that meant high school geometry:

 Not really the work I did, but it's the basic problem, if I remember correctly. The rest involved tangents and sine/cosine stuff. I don't remember.

Not really the work I did, but it's the basic problem, if I remember correctly. The rest involved tangents and sine/cosine stuff. I don't remember.

After cutting the Illustrator-generated circles appropriately, I made it into a series of symbols I could paste together. Once a line is finished from Baltimore to wherever, I stitch each of the line segments together and move them onto the right layer. The final product doesn’t look quite as neat as the original straight line, but I think the result is pretty good.

From a historical perspective, there aren’t really ferry-fans in the same way there are railfans. Schedules, wharfs, and old maps are very difficult to find online, leaving me to hunt around on Google Maps for clues as to where a given ferry actually landed.

Of course, most of these towns don’t even exist anymore, if they ever were more than a pier in the middle of the countryside. That means the only way to know on which side of the river a wharf was is to look for the wharf road, which generally does still exist, or find some subdivision named for local geography.

All in all, this is a much more laborious process than a simple rail line, but it is well worth it. Many times, these ferry runs were the only easy way to get to remote river and island communities. Even if they only ran once a day or even once a week, they were a lifeline. I can only imagine what it was like to go on an overnight river cruise from Baltimore to West Point or Washington with the most backcountry of folk. The whole point of this project is to lift the veil of expertise that shrouds historic transportation networks, and this important part of the network is very much shrouded.