[Accessibility] Best way to map sidewalks ?

[Clifford Snow]

On Sun, Jan 17, 2021 at 8:11 AM pierrick pratter via Accessibility <
accessibility at openstreetmap.org> wrote:

> Opensidewalk proposal is still in "draft" status since 2016 and has never
> been voted on and AccessMap.io doesn't seem to use OSM for sidewalk data, I
> have compared the map of seattle and OSM and part of the city are mostly
> not mapped with sidewalks at all way there not even the crossing nodes, so
> the routing system seem to use a different DB
>

Sidewalks in Seattle have been continuously updated while AccessMap is
likely using data that is very stale. But it is using OSM data as can be
seen by looking at the github page for AccessMap.io. AccessMap.io also has
my city's OSM data the only available data source. AccessMap.io does use
the City of Bellingham's open data for routing.

Mapping sidewalks as separate ways is well documented in the wiki. See
https://wiki.openstreetmap.org/wiki/Sidewalks and
https://wiki.openstreetmap.org/wiki/Tag%3Afootway%3Dsidewalk

>
> The only drawback I see from sidewalks as metadata is geometry as parkings
> lanes have their tags (
> https://wiki.openstreetmap.org/wiki/Key:parking:lane ) and kerb height
> can be added on the crossing node or on the road itself.
>
> Routing system already exploit elevation data like Osmand without needing
> the tags on each way.
>

FYI - AccessMap uses elevation data from a separate source, like OSMand and
Brouter.

>
> An app that I tried for visually impaired people is GetThere (
> https://play.google.com/store/apps/details?id=com.LewLasher.getthere&hl=en_US&gl=US
> ), and it seems to base itself on the structure of the street
> (street-crossings and main street itself) to route it's users.
>
> For wheelchairs I only found OpenRouteService (
> https://maps.openrouteservice.org/ ) that works for Europe only and
> require to have everything mapped as a separate way, but it is not because
> OpenRouteService is built this way that the OSM community as to map this
> way.
>

OpenTripPlanner, OTP, does use either method for routing although it seems
to randomly use the street instead of the sidewalk.

>
> This way of mapping as to be thoroughly discussed, I didn't find any up to
> date talk with a lot a participant that ended with a voted proposal and I
> feel that it as not been thought in the way the OSM database is built, as
> sidewalks are part of a road like parkings lanes or even cycleways it is
> logical and easier to maintain than a whole cities with interconnected
> lanes.
>
>
> This is why I wanted to have feedback from associations, or even users
> themselves because I don't see this schema used anywhere else than some
> cities and our job as contributors is to keep the data as easy as possible ?
>

Another way to look at what we do is mapping what exists. Obviously there
are two distinct ways to map sidewalks. I choose mapping sidewalks as
separate ways because I believe that creates a better resource for routing
engines to avoid barriers to pedestrians especially those in wheelchairs.
Impressively, footway=sidewalk has more than 2M instances according to
taginfo.

Best,
Clifford
-- 
@osm_washington
www.snowandsnow.us
OpenStreetMap: Maps with a human touch
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