[OSM-dev] Highway Statistics: counting the number of roads along a junction/roundabout

Peter Wendorff wendorff at uni-paderborn.de
Mon Jan 28 12:08:42 GMT 2013


Hi.
I guess most of the roundabouts are not modeled as a relation, and I 
don't think that would be necessary.
A roundabout should be a closed way tagged as highway=roundabout.
=> to get all roundabouts fetch all ways tagged as such.

To count all ingoing/outgoing streets for all roundabouts, I would
- fetch all nodes of that roundabout
- for each of these nodes fetch all ways connected to it
- count them.

Additionally you should
1) look for oneway tags: only ingoing/outgoing
2) for dual carriage ways, especially trunk roads, but often in cities 
that applies to other road types as well, probably you want to find out 
if a pair should be counted as one street only: one ingoing oneway, one 
outgoing oneway, usually they are neighboured, roughly pointing to the 
same direction, and share the same name.
3) depending on your use case ignore footways as they are often 
sidewalks just crossing.

regards
Peter

Am 28.01.2013 12:27, schrieb Martin Alegre:
> Dear all,
>
> I need to generate some statistics on highways. More precisely, given 
> an OSM file of a city, I would like to find out which is the average 
> number of roads along a junction/roundabout?
> Does anybody has some experience doing that? Given the OSM 
> documentation, it seems to be, that the only way to do that is by 
> looking for <relation>'s, right? My intuition is that
> if inside a given <relation> ... </relation>, a junction exists, then 
> the rest of <way>'s inside that <relation> are the roads along that 
> junction. Is this reasoning correct?
> I'm thinking of using Osmium for that purposes.
>
> Best
>
>
> _______________________________________________
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> dev at openstreetmap.org
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