Am 22.03.2011 19:59, schrieb M∡rtin Koppenhoefer:
2011/3/22 Peter Wendorff<wendo...@uni-paderborn.de>:
...it is a tag that you use
only on independent ways. The sidewalk is already comprised in the
main road according to our data model,
Where is this data model? I would say: nobody thought about sidewalks at
creating the data model - it's not defined.
If you claim that highway=residential includes sidewalks, that's new to me -
and neither proofed nor (well) documented
http://wiki.openstreetmap.org/wiki/Editing_Standards_and_Conventions#Divided_highways
"A divided highway (also separated highway) is any highway where
traffic flows are physically separated by a barrier (e.g., grass,
concrete, steel), which prevents movements between said flows. "
By foot I can cross grass without any problem - probably without
perceiving it - same by bike.
By foot I can cross concrete and steel probably, too - while not without
perception.
While in the case of sidewalks there is indeed a physical separation
(the kerb), it still doesn't quality because that kerb doesn't prevent
movements between said flows.
Sitting in a wheelchair and being 60 years old most probably I am
prevented from crossing a curb of 12cm height - at least upwards.
You start to wide the scope of OSM from car drivers to pedestrians - but
you don't want to spread your scope to more!?
and adding a separate highway=footway indicates that there is a barrier
between the footway
and the road.
There is! Ask the next wheelchair user or old man/woman with a walking frame
about the barrier a curb of normal height is for him.
I agree that this part of our model is not very mature, and that it is
always relative to the means of transportation if a barrier is
preventing movement or not. Also in the case of dual carriageways you
might physically be able in some cases / with some vehicles to change
to the other way, even if not legally permitted.
Still I keep the idea that sidewalks should be mapped in another way
then independent footways, and this other way should not redefine
highway=footway (i.e. use another tag). Any tagging of them with
highway=footway is tagging for the routers/renders.
I remember the big discussion about natural=tree.
The critics there has been the meaning of the ancient proposal: tree
should stand for lone standing or significant trees
The question was: Is it correct to add a "only" to that sentence or not?
The same I see in your argumentation:
Footway was intended to map footways. Nobody - probably - thought about
mapping sidewalks at that time.
I agree: there should be a distinction - that's why footway=sidewalk is
our solution for that.
But to say, sidewalks are NO footways, is definitely wrong.
Yes: you can say, the highway=footway is mapping for the renderer - but
I don't care about the standard renderer to display sidewalks everywhere
and everytime. I can perfectly life with saidewalks not being rendered -
or only, if the space is left.
But I don't see the argument to not map sidewalks as footways.
If you don't want to render sidewalks in zoom levels up to 17 or 18
(higher zoom levels have enough space to render it nearly everywhere),
you CAN exclude sidewalks mapped with highway=footway, footway=sidewalk
very easily.
Mapping for the renderer would be to not use highway=footway - because
the renderers does not interpret footway=sidewalk in a good manner, yet.
regards
Peter
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