[Tagging] sidewalks and tagging for the renderer

[Martin Koppenhoefer]

Am 11. April 2012 10:49 schrieb Komяpa <me at komzpa.net>:
> First, there are road behaviour rules, that basically disallow that.
> You MUST go to crossing to cross a road here.


you can't asume this to be a global law. In other countries (e.g.
Germany or Italy) you must use a pedestrian crossing if it is close to
you. If you are more then x meters away (i.e. you are in the middle of
a road) you can simply cross anywhere, provided you don't endanger the
traffic or yourself. I find it difficult to believe that belarussian
law urges pedestrians to only cross on a crossing, and if there is
none, they will have to walk kilometers just to cross the street, or
did I get this wrong?


> Second, if you want to hide sidewalks on rendering, postgis's
> ST_DFullyWithin is your friend. You don't have to TAG everything you
> can rather easily distinguish geometrically.


in the case of parallel ways it is impossible to tell whether you can
filter them out or not (there could be a separation or they could be
on different height levels), especially if people are mapping
sidewalks the same as separated footways. My main concern is routing,
not rendering. I wouldn't take them into account in routing, because I
feel you would get worse results.
E.g. 100 m South of the spot you posted above:
http://www.openstreetmap.org/?mlat=53.865988&mlon=27.651201&zoom=18&layers=M
Imagine you stand there and want to go to the parking on the other
side of the road:
http://openrouteservice.org/index.php?start=27.6511152,53.8661793&end=27.6513996,53.8661698&pref=Pedestrian&lang=de&noMotorways=false&noTollways=false
http://openrouteservice.org/index.php?start=27.6526656,53.8626553&end=27.6529552,53.8627217&pref=Pedestrian&lang=de&noMotorways=false&noTollways=false
You find this everywhere:
http://openrouteservice.org/index.php?start=27.6555434,53.866273&end=27.6557157,53.8662298&pref=Pedestrian&lang=en&noMotorways=false&noTollways=false

Another similar issue is that with these sidewalks people often don't
connect crossing footways to the street, they only connect them to the
sidewalk. There are examples for this also in your area, so
unfortunately simply omitting them won't do the job either, because
you would get gaps near crossings.


> Third, try to cross these not on the crossing staying alive:
> http://upload.wikimedia.org/wikipedia/commons/thumb/1/14/Partyzanski_praspekt_8.jpg/300px-Partyzanski_praspekt_8.jpg
> http://kp.ru/f/4/image/26/67/396726.jpg


I'll do next time I visit your town. What should be the problem? You
wait until there is no car coming or all cars stop and then you cross.

cheers,
Martin