Some thoughts that trouble me... To me it seems obvious that width values, independently on how they are measured, are at best estimates, as measuring them is in most cases dangerous or requires good technical equipment. I guess that most width values in the database are reality estimates (I don't think that this is an unjustified extrapolation from my own mapping - 99.9% of my width tagging based on estimates). Estimates are relatively easy for narrow roads if you have street-level photographs. They become much more unreliable for wider roads. I solve this by using only lanes count for wider roads. Precise width measurements are difficult to impossible, but fortunately they are also less important than the lanes count for the end user.
The discussion about including/excluding sidepaths/sidewalks becomes also irrelevant if we were only to use the lanes count as that counts only motor traffic lanes. Would also overcome another aspect of the width definition: If we use width for the entire road, i.e motor-traffic lanes, shoulders, sidewalks, cycle lanes/tracks/paths, tree rows between foot and cycleway, ... we do in the end not know enough about the the actual widths of the different component "lanes". Width values are useful and easy to estimate from street-level photographs for sidewalks, cycle paths/lanes/tracks, certainly to within 0.5m precision. We need in any case a good system for regrouping parallel ways that belong to the same street. A relation seems to me the better option, but in any case, whatever approach we pick now, we will face an nearly impossible amount of retrofitting work. Anything we do on this from now will not make the problem go away with the existing stock of data. Volker <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Virus-free. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> On Fri, 18 Sep 2020 at 22:35, Tobias Knerr <o...@tobias-knerr.de> wrote: > On 17.09.20 02:35, Taskar Center wrote: > > This is yet another example why "sticking" the sidewalks onto the > > highway (as a tag) rather than mapping them as separate ways is > > appearing to be less and less practical. Please see our sidewalk schema > > proposal > > <https://wiki.openstreetmap.org/wiki/Proposed_features/sidewalk_schema> > > from several years ago. > > Your sidewalk proposal unfortunately doesn't really address the crucial > shortcoming of separately mapped sidewalks: The lack of a reliable > mechanism for figuring out which section of road a given sidewalk way > belongs to. > > I agree that we should be able to give sidewalks their own geometry, but > we _also_ need the relationship between sidewalk and road. So far, all > the proposals attempting to support the former end up sacrificing the > latter. > > There have been some promising discussions recently around the > sidepath_of idea, but that's still just brainstorming. Until a practical > solution is found and actually used in the database, sidewalk mapping > will remain a choice between two options that are broken in different ways. > > As for the main issue of the thread: I would welcome a clear definition > for the meaning of width. In my own mapping and when writing the > relevant code in OSM2World, I have counted sidewalks etc. as part of the > road's width if they are mapped as tags on the main way. But I would of > course change that if there finally was a documented and widely > agreed-upon recommendation. I don't care so much which one it is - but > we need one. > > _______________________________________________ > Tagging mailing list > Tagging@openstreetmap.org > https://lists.openstreetmap.org/listinfo/tagging >
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