Hi Tobias.
On 26.08.2010 23:52, Tobias Knerr wrote:
On 26.08.2010 22:25, Peter Wendorff wrote:
My approach would be - and I would like to get your opinions on that:
- a sidewalk is tagged like every other footway
highway=footway|path
(foot=yes)
(segregated=yes|no)
footway=sidewalk
name=NAME-OF-STREET
I understand why you like this approach: The mappers will essentially
draw the routing graph for you. ;-)
Well - yes, that's a good aspect, too - but not the only one.
Generally, individual ways for sidewalks and cycleways make it easier to
use the data for navigation, while adding tags (or relations) to the
roads themselves appears somewhat easier for renderers.
that depends...
I happen to write a (3D) renderer at the moment, so I assume this will
create some challenges for me. Simply drawing the footways and roads
independently will certainly look bad - there will either be gaps
between the sidewalk and the road or they will overlap. Unless, of
course, the distance between the sidewalk way and the road way is
exactly half the sum of their respective width tags' values ... which is
unlikely, to say the least. *g*
That's true, yes. I would like to add one (but not sure what is the
best) of the multilane-proposals - perhaps even the area proposal to it,
but that should be compatible AFAIK. If applied, you could decide wether
to render sidewalks separately or with a different implementation from
the informations you get via the relations.
Only using the relations I fear your problem is not solved, too:
Consider a street where at the side is a sidewalk, and in between
constantly changing a strip of grass, parking line, both of them, nothing.
How would you render that only using tags or relations?
I think there are issues where simply using the relations will fail, too.
So I will need to associate sidewalks with road sections. And therefore
- no geometric analysis necessary (finding parallel streets to unnamed
footways)
... I *will* need to do geometric analysis.
I agree - but did you think you can write a RENDERER without doing
geometry? :D
It's still possible, though (or so I hope, at least...), so your
proposed solution would be acceptable for me. It's actually nice that it
works well with today's editors, while other approaches require editor
or even API improvements. This will probably lead to fast adoption by
mappers.
2) dedicated sidewalks make it a lot more simple to tag crossing details
like islands etc.
Could you describe crossing layouts in more detail? I assume you would
model them like this
A B C
| | |
| | |
*--o--*
| | |
| | |
where A and C are sidewalks, B is a road, and *o are junction nodes.
If we use the existing tagging for crossings, then node o should be
tagged highway=crossing + crossing=island/...
except of that I prefer to explicitly tag crossings, yes.
So how would you tag the horizontal way? May I suggest that it is tagged
differently from A and C to make it easier to distinguish in software?
Currently I don't tag it differently. It's a footway/path as the
sidewalks are, too.
I use to add sloped_curb and tactile_paving to every crossing, but you
are right - that should be optional perhaps.
Applying sloped_curb and tactile_paving allows me to identify the way
you propose to tag different as "the way between sloped-curb and
sloped-curb with highway=crossing on the node(s) in between".
But you are totally right.
Any ideas how to call the crossing-way?
Highway=crossing is ambiguous with the crossing node itself and
therefore I would like to find another tag here.
Peter
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