Render area:footway

[ZeLonewolf]

Recently, there have been a series of edits on foot paths in Washington, DC. (See the history of:
https://www.openstreetmap.org/relation/12194017)

In summary, the area of these footpaths were tagged highway=pedestrian + area=yes, presumably because that combination currently renders in Carto. However, the area of foot paths are not correctly tagged highway=pedestrian based on the wiki description of this tag. On review of the wiki, it seems like area:highway=footway is the best available option for tagging the area around footways. However, this tag does not render in Carto.

I suggest that the tag area:highway=footway ought to render in the same style as highway=pedestrian + area=yes. This will provide a rendering tag for footway areas and discourage inappropriate usages of highway=pedestrian.

[ZeLonewolf]

Showing difference between rendering footway areas and current behavior (based on partial tile refresh):

[501Ghost]

A side-effect of this is that it encourages people to map more area:footway because it will render nicely, but I don't think that's what we want. We want to encourage people to spend their time mapping more interesting things.

[jeisenbe]

@ZeLonewolf this is a partial duplicate of #180 which requested rendering of all area:highway= features way back in Sep 2013, and was closed as declined. This comment explains why most concisely: #180 (comment)

The request has been made a couple of other times, e.g. #1483, but it remains not feasible technically once we consider what will happen with bridges and tunnels

[1ec5]

Are the technical and stylistic considerations still significant if area:highway=pedestrian is treated as an alias of highway=pedestrian area=yes but other area:highway values continue to be unsupported? Seems like any issue around layers and bridges already affects pedestrian areas anyways.

[imagico]

The main consideration speaking against that is the lack of a viable long term strategic concept behind the idea.

All of the issues with rendering area:highway=* in general of course also apply to rendering area:highway=pedestrian. Some of them already cause problems with existing rendering of highway areas (see #529, #2046 and #3872 in particular).

There are also still very unclear semantics about the whole area:highway mapping concept. When the idea was originally developed some wanted there to be a 1:1 relationship between linear highway ways and area:highway polygons. But some think that an area:highway polygon can - like in the example linked to above - also correspond to dozens of linear highways with complex topology. If and how tunnel and bridge tagging should be applied to area:highway polygons is also something where there seems to be no agreement on. Taginfo shows 385 area:highway features with a bridge tag and 152 with a tunnel tag (of 170k features in total). So this is not a common practice. Does that mean the polygons should inherit the bridge/tunnel status from the linear highways? But that would require the mentioned 1:1 relationship - which is practically not maintained either.

Finally we would not want to incentivize mappers to manually buffer the linear highways to map constant width roads/paths so if we would want to render area:highway polygons we definitely would want to equally render roads with a width tag in their ground unit width at higher zoom levels - which is technically challenging as well and would require revising the decision on ground unit rendering (#1290).