[Imports] [Talk-us] Proposing import of sidewalk data Seattle, WA, USA

Andy Townsend ajt1047 at gmail.com
Tue Aug 2 13:55:20 UTC 2016


On 01/08/2016 22:35, Meg Drouhard wrote:
> Hello,
>
> We are proposing to import open municipal sidewalk data from the city 
> of Seattle as described in this proposal: 
> http://wiki.openstreetmap.org/wiki/Seattle,_Washington/Sidewalk_Import.
>
> Imports will be tagged according to the sidewalk schema that we 
> propose here: 
> http://wiki.openstreetmap.org/wiki/Proposed_features/sidewalk_schema. 
> The schema is a proposal for standardization of conventions, rather 
> than changing or adding tags, and it is particularly concerned with 
> features of sidewalks that may aid or impede travel for people with 
> limited mobility.

 From reading that a number of potential issues occur to me - one of 
which is that it does appear to be a change to the way that crossings 
are mapped.  Your page says "recommend crossings be mapped as ways".  
http://wiki.openstreetmap.org/wiki/Tag:highway%3Dcrossing currently 
suggests nodes only (and there are people out there avidly changing 
crossings mapped as ways to crossings mapped as nodes). Whilst this may 
just be a clarification issue, at the very least you'd want to liaise 
with them so that you get their input.  Perhaps some examples (on the 
dev server) would help?

Whilst I can understand why you'd want to map e.g. drop kerbs for 
wheelchair use, I think you need to remember that most of the world is 
not like Seattle.  In most places in the world jaywalking isn't even a 
concept and you can cross a road anywhere that you like.  How are you 
going to model this?

Also on 
http://wiki.openstreetmap.org/wiki/Proposed_features/sidewalk_schema 
you've said " According to Routing/online_routers, routing options for 
pedestrians, wheelchair users, and blind persons significantly more 
limited than other routing use cases.".  This simply isn't the case for 
pedestrians - I'm not aware of a mainstream handheld router using OSM 
data that _doesn't_ support pedestrian routing.  My experience is that 
handheld routers often get confused when sidewalks are mapped 
separately, not because it's inherantly a bad idea, but because people 
tend to make a mess of it.  Mapping sidewalks as a separate way is (in 
both volume and connection terms) harder than mapping as 
left/right/both; there's more for mappers, especially new mappers, to 
get wrong.

Perhaps it would help to explain what you're proposing to do if you were 
to take a couple of examples of roads with and without sidewalks 
elsewhere in the world both north and south of the equator and show 
(again perhaps on the dev server) how you'd change them to sidewalks 
mapped according to your proposal?

One other question - how would I (from a routing / rendering 
perspective) know that "this road has a sidewalk" or "this sidewalk is 
adjacent to named road X"?  In my case I'm asking that because I'm 
rendering sidewalks as per 
http://www.openstreetmap.org/user/SomeoneElse/diary/38136 , but it's 
also relevant from a routing perspective as well.

Best Regards,
Andy




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