[Tagging] Formally informal sidewalks

Svavar Kjarrval svavar at kjarrval.is
Fri Jul 14 10:20:03 UTC 2017

On fim 13.júl 2017 13:49, Andy Townsend wrote:
> Perhaps a few links to photos would help?
> It'd make it a lot easier for other people to visualise.

Don't think I have such photos on me and I'm fairly sure some people
wouldn't want links to copyrighted photos in Google Street View. I'll do
the next-best thing and provide links to OSM locations. If people check
them out on Google Street View or via other such sources, it would be
their business. The areas are mainly picked for visualisation, not
because I've found any specific routing issues.

A street segment with no sidewalks on either side:

A street with a sidewalk on either side but no marked crossings:
(Sidenote: If one tries to route from no. 73 to 42,
GraphHopper suggests a long route while Mapzen assumes the user is
already on the other side of the street)

A street segment where the paved sidewalk ends prematurely (same as I
described, except they do widen the street in that case):
(Sidenote: I do wonder if it would be alright to put a sidewalk talk on
the road segment at the end of that street)

On fim 13.júl 2017 14:08, John Willis wrote:
> In places complicated enough to warrant separate footpaths, then assuming they *cannot* cross the street wherever they want (and forced to go to crosswalks or signals) is by far the best choice. But where this complicated sidewalk tagging ends, and the minor, residential, and service roads without sidewalks begin interests me greatly. Is there a “footway_link” ? Not a traditional _link road, but a logical link to when sidewalks end - do they need some kind of “link” to the adjacent road so Routing continues on?
That's one of the issues I've been wondering myself. Routers seem to
have a hard time knowing when it's alright to suggest the user "jump"
onto the sidewalk from the road or vice versa if there isn't a footway
such as ones used for crossings. In cases where the footway ends
prematurely, the routing software doesn't know it may suggest such a
"jump" onto the street or not, and would be likely to give up on that
segment. I do understand there are probably justified reasons for them
not to do it without positive data allowing them to, so we might need to
input some type of data (like a link) telling the routing software that
such a connection is fine in that case. Sadly, I'm not sure what method
I'd be allowed to use since I haven't been able to find any tag or
method to do it.

On fim 13.júl 2017 14:17, marc marc wrote:
> can you give an exemple ? I never see this problem.
> I just test GraphHopper and Mapzen on 2 streets without sidewalk without 
> any routing problem.
This is, of course, not a problem when finding routes between two houses
on the opposite side of the street. There are problems where the routers
discover a footway nearby but that footway leads to a much longer route
when in fact it would be much quicker to walk on the street itself, as
the "common sense approach" would expect.
Here is an example of that:
(Sidenote: If one moves the points much closer to the street of
Aflagrandi, the routers will finally "get it", but these are not the
coordinates people would utilise when looking up the starting point and
the destination point.)

With regards,
Svavar Kjarrval

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