[Accessibility] Question about accessibility tagging, key:incline, and sidewalks

[Michael Maier]

On 24/01/16 23:09, Charles Basenga Kiyanda wrote:
> Hi,

> From an accessibility point of view, is it better to map the sidewalk as
> a separate entity or to specify the existence of the sidewalk as
> metadata on the way representing the street? 

Hi Charles,

I have supervised several wheelchair-mapping projects in Austria, and
from my experience the only viable solution is mapping the sidewalks
separately.

One of the major reasons is the correct mapping of kerbs (or curbs) and
their height. Only if the kerb is mapped as a point on a line, a router
can decide if it is a barrier or not (a kerb can be a small step for a
man, or an insurmountable obstacle for a wheelchair user).

You can see an example crossing with kerbs here:
https://wiki.openstreetmap.org/wiki/File:Crossing_a2l.png
The JOSM style used is "Wheelchair Routing Attributes", it can be found
in the "Map Paint Styles" setting.
I've also created an accompanying preset called "sidewalks, kerbs &
entrances 4 wheelchair-users".

Other arguments for explicit mapping of sidewalks include:
* calculation of segment lengths for routers is more exact
* traffic signals can be circumvented if only valid for cars
* simpler tagging with a lot less prefixes
* easier to implement for routers


As a sidenote to inclination, do you also map the lateral inclination of
ways? We've used the tag "incline:across" for that, as this is also a
criteria for wheelchair accessibility.

> Thanks very much,
> 
> Charles

I've also set up a (small) demo instance of an OSRM with two profiles
(normal and electro wheelchair) on my private server, which works well
with explicitly mapped sidewalks:

http://mm.linuxtage.at/osm/routing/wheelchair-normal/?z=18&center=47.074194%2C15.449508&loc=47.074336%2C15.449848&loc=47.074871%2C15.451916&hl=en&ly=&alt=&df=&srv=

As this is my private test server, only Austria is imported, and it will
not be online for any longer than end of February. But feel free to use
the profiles for setting up your own instance!
https://github.com/species/osrm-wheelchair-profiles

If you have any questions, just ask :-)

Michael

-- 
Michael Maier, Student of Telematics @ Graz University of Technology
OpenStreetMap Graz                         http://osm.org/go/0Iz@paV
http://wiki.osm.org/Graz
http://wiki.osm.org/Graz/Stammtisch

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