[OSM-talk] Sidewalk symmetry

Jmapb jmapb at gmx.com
Tue Apr 17 20:30:06 UTC 2018


The wiki contains some suggestions/guidelines about when to map 
sidewalks as separate footways versus when to encode them as tags on the 
main road. The basic recommendation seems to be that if there's a 
barrier or even a strip of grass between the two, a separate way is fine 
and even sometimes preferred (and the road should be tagged 
sidewalk=separate to indicate that it's been mapped as a separate way), 
but if the sidewalk is directly adjacent to the road, better to just 
imply it with a sidewalk=left/right/both tag.

My gut tells me that a corollary should be: If the sidewalk on one side 
of the road is mapped as a separate way, then the sidewalk on the other 
side (if there is one) should also be a separate way, even if it's 
directly adjacent to the road due to asymmetry of sidewalk design. Does 
this sound right? I certainly don't see any clean way to tag a road to 
indicate that one of its sidewalks has been mapped as its own way and 
the other hasn't.

(My personal feeling is that that it's better to avoid mapping sidewalks 
as separate ways unless there's a compelling reason that would outweigh 
the additional data clutter and routing complications. In some 
circumstances -- those where walking on the sidewalk, or on a particular 
side of a road with two sidewalks, has noticeably different routing 
implications -- it seems like a good idea.)

Thanks for you thoughts, jmb




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