User:Rjw62/Draft Guidelines for Sidewalk Mapping

Preamble

Opinions vary on whether it is better to map sidewalks (footpaths alongside roads; "pavements" in British English) as separate parallel highway=* ways in OSM, or simple describe them by adding tags to the main highway=* way that runs along the centreline of the road. Proponents of mapping separate ways point to the greater detail/precision this adds, and how it is the only way to allow proper pedestrian routing through complex intersections. Proponents of adding sidewalk* tags to the main highway argue that the whole highway is really one object (with different lanes for different traffic), and mapping the sidewalks separately can break routers.

This page aims to provide guidance for those wanting to map sidewalks separately, in order to reduce the problems it can cause, particularly for routers.

This page is currently a draft. Items that I think might be particularly controversial, and/or need further discussion are  highlighted in yellow .

Guidelines

If you are going to map sidewalks as separate ways in OSM then...

• Map the routes that are physically present
  Sidewalk ways should follow the pavement centre-line / natural walking route taken by pedestrians using them. Crossing nodes should be mapped at the actual position they exist at on the ground. If there is no physical sidewalk present on a particular side of the road, then do not map one there, even if people may chose to walk in the carriageway along that side.

• Tag both the road and sidewalk ways appropriately
  Add tags to the road and pavement ways to confirm that the routes are separately mapped sidewalks, to help data users understand the relationships:
  • Add footway=sidewalk on the sidewalk itself
  • Add sidewalk=separate on the associated road

• Tag the road name on the sidewalk
  Add the name of the road to the sidewalk,  using one of the in-use tags street:name=* or is_sidepath:of:name=* . This also helps data users and routers understand the sidewalk is part of the main road.

• Map all the crossings
  Ensure all designated crossings of the road are are mapped as ways between the sidewalks and the main road, so that they're available for routers to use. This includes signal-controled crossings, zebra crossings, and crossing points that are only indicated by a dropped curb (with or without tactile paving). The crossing route should be tagged with highway=footway + footway=crossing. The node at the point where the main road and the crossing way meet should be tagged with highway=crossing and other appropriate tags to describe the crossing. (Note that it may not be possible to do all this from aerial imagery alone. Local knowledge, a site visit or street-level imagery may be required.)

• Make sure connectivity is maintained
  Ensure that connectivity is maintained for routers between the road and sidewalks by
  • Continuing the sidewalks across any side roads if that would be the natural route for pedestrians to take, even if there is no crossing infrastructure present. (The section of the way that actually crosses the side road, would be better split from the sidewalk way, and tagged as footway=crossing.)
  • Where another path joins the sidewalk from the side, continue this way across the sidewalk and connect it to the main road, unless there is a convenient crossing point close by that is mapped.
  • Ensure that the end of any separately mapped sidewalk is connected back to the main road, either by stopping at a side road, driveway or connecting path,  or by adding an artificial link way with highway=footway + footway=link .
  •  Add any additional links between the sidewalks and the main road needed to cover natural desire-line crossing points.