Differentiate vehicle ferry routes

[quincylvania]

Whether or not you can drive onto a ferry is a critically important detail for route-planning and navigation. But OSM maps tend to render all ferry routes the same way. This is a good opportunity to innovate.

In the below example, one route is a massive oceangoing vessel that fits RVs, the other is a motorboat that might fit a couple dozen people, tops. It's impossible to tell the difference in the rendering.

Another consideration is that of tolls. There are a number of toll-free car ferries in the US and Canada, meaning tolls shouldn't be implied. Since toll roads are rendered distinctly in americana, tolled ferries might should be as well.

[ZeLonewolf]

It looks like the transportation_name layer does not have toll tagging, so we would have to get that added to OpenMapTiles. (OSM object, tile feature). This should be a pretty straightforward add, though it would help our case to have some examples of paper maps that differentiate this.

[1ec5]

It seems like there isn’t very much precedent for distinguishing ferry lines by their characteristics in print maps, at least in the maps in my collection. I don’t have any examples of maps that give auto ferries a different color or dash pattern than passenger ferries, for instance.

In fact, in their maps of New York State and California, Rand McNally treats any ferry as exotic enough to warrant a generic “Ferry” label:

In this map of Long Island, the American Map Company labels every passenger ferry as “Passenger Ferry” instead of by its name. They also provide an inset with phone numbers of automobile ferries to call for fares and schedules.

The Kentucky Transportation Cabinet’s official state highway map does indicate that the ferries they operate are tolled, while the Louisiana Department of Transportation and Development labels free ferries on their map:

Engels Maps, a local publisher in the Cincinnati area, goes a step further, labeling the ferry with the exact fare for cars. This ferry had a famously consistent fare for many years, though they’ve since raised the rate.

The Washington State DOT’s official map shows not only state route shields on its ferry lines but also “Passenger Only” and duration labels:

[quincylvania]

@1ec5 Thanks for the rundown! Its clear paper maps tend to treat ferries are unusual enough and complicated enough to just describe them with labels. But the labels do specify toll vs. free and vehicle vs. passenger, so I think there's precedent to distinguish them somehow in Americana. Text-only is one option, but I think we can do better with the lines, even if slightly.

Here's another example from NPS (no stroke differences):

[1ec5]

Yes, I think there are a few possibilities here:

• At a zoom level low enough that a ferry line is barely visible, apply a point-placed label instead of a line-placed label.
• Clearly label “passenger” versus “vehicle”. Are these two modes sufficient, or do we need to distinguish permission to carry a bicycle on board? Is the ferry’s name important enough to show alongside this information?
• Clearly label free versus tolled, in keeping with our existing treatment of toll roads.
• The NPS map indicates seasonality. I think we should consider a “seasonal” gloss for roads as well as ferries: Append gloss to labels of exotic road types #503.

This possibly calls for several new fields to be exposed through OpenMapTiles. I think it would be the style’s responsibility to come up with the descriptive text, because it needs to be localized and could depend on the available space. We could even decide to represent these attributes using icons beside labels, similar to public transportation maps.

[ZeLonewolf]

Since the toll attribute already exists in the transportation layer, this is probably the easiest add. However, I think we would need to add ferry tolling information to the transportation_name layer if we wish to use text labels rather than a line treatment. So I think that styling choice needs to be determined before I can submit a PR to OpenMapTiles. I also proposed in the linked ticket that we only tag the toll=no case, which should be the rarer situation.

[quincylvania]

At a zoom level low enough that a ferry line is barely visible, apply a point-placed label instead of a line-placed label.

I like this a lot, just have to see if it's useful in dense places with lots of ferries.

Clearly label “passenger” versus “vehicle”. Are these two modes sufficient, or do we need to distinguish permission to carry a bicycle on board?

I count 381 ferry routes in OSM with foot=yes and bicycle=no. There must be more without proper access tags. This is an edge case, but it would be useful to display if feasible, at least when bikes are disallowed. No one wants to bike to a ferry just to be denied boarding.

Is the ferry’s name important enough to show alongside this information?

OSM typically just puts "Origin-Destination" (with various formatting) in the name tag. I think this info is quite useful when the route is too long to show entirely on screen at once (based on the zoom). But to improve formatting and localization, it might be better to use the from and to tags instead of name. Though there are cases where name has something useful, like the Staten Island Ferry.

I think we should consider a “seasonal” gloss for roads as well as ferries

Agreed.

We could even decide to represent these attributes using icons beside labels, similar to public transportation maps.

I'd be interested to see what this might look like. We could also adjust the icons for the ferry terminals to indicate access if all the ferries terminating there have the same access. Like this for passenger ferry terminals:

[1ec5]

We could even decide to represent these attributes using icons beside labels, similar to public transportation maps.

I'd be interested to see what this might look like. We could also adjust the icons for the ferry terminals to indicate access if all the ferries terminating there have the same access.

Similar to how NPS maps append amenity icons to place labels, we could append mode-of-transportation indicators to the ferry labels using a format expression:

We could keep the icons small and match them to the label color to avoid drawing too much attention. That said, I think glosses would be straightforward enough and well-justified by existing maps. We have a legend now, but we probably shouldn’t rely too heavily on it, since users aren’t guaranteed to consult it.

[1ec5]

AAA’s Hawaii map is a rare map that distinguishes auto and passenger ferry lines by color: