[OSM-talk] Overpass API / Overpass QL: center (and centroid) function?

[Christian Quest]

In my last overpass test with the new "out center" feature, it looked like
it was working only with XML output, not with the JSON (not GeoJSON) one.


2014-07-24 16:30 GMT+02:00 Stefan Keller <sfkeller at gmail.com>:

> Thanks again - I think I got it - including a bug:
> GeoJSON is still returning polygons! But with XML it works.
> E.g. replacing "[out:json]" with [out:xml] or exporting as XML.
>
> --Stefan
>
> 2014-07-24 15:48 GMT+02:00 Pierre Béland <pierzenh at yahoo.fr>:
> > Stefan,
> >
> > In your example, the parenthesis are making a union of the two requests.
> and
> > the greater then ( > ) is doing a recurse request.
> >
> > This example below is working. It extract independantly nodes and ways,
> > calculating the centroid for the ways.
> >
> > [out:json]
> > [timeout:25]
> > ;
> >
> >   node["shop"~"dairy"]
> >
> (45.70234306798271,5.8831787109375,47.864773955792245,10.590820312499998);
> > out meta;
> >   way["shop"~"dairy"]
> >
> (45.70234306798271,5.8831787109375,47.864773955792245,10.590820312499998);
> > out meta center qt;
> >
> > Pierre
> >
> > ________________________________
> > De : Stefan Keller <sfkeller at gmail.com>
> > À : Pierre Béland <pierzenh at yahoo.fr>
> > Cc : Talk Openstreetmap <talk at openstreetmap.org>
> > Envoyé le : Jeudi 24 juillet 2014 9h44
> > Objet : Re: [OSM-talk] Overpass API / Overpass QL: center (and centroid)
> > function?
> >
> > Salut Pierre
> >
> > Thanks - But this doesn't parse (see below). I'm getting:
> > Error: line 4: static error: Element "print" cannot be subelement of
> > element "union".
> >
> > -- Stefan
> >
> > [out:json]
> > [timeout:25]
> > ;
> > (
> >   node["shop"~"dairy"]
> >
> (45.70234306798271,5.8831787109375,47.864773955792245,10.590820312499998);
> >   way["shop"~"dairy"]
> >
> (45.70234306798271,5.8831787109375,47.864773955792245,10.590820312499998);
> >   out meta center;
> > );
> >>;
> > out meta qt;
> >
> > 2014-07-24 15:20 GMT+02:00 Pierre Béland <pierzenh at yahoo.fr>:
> >> Stefan,
> >>
> >> In your request, you make a recursive query that loads nodes from the
> way.
> >> In this example, the node and way queries are independant. For the way,
> >> the
> >> center command is used.
> >>
> >> [out:json]
> >> [timeout:25]
> >>
> >> ;
> >>
> >>  node["shop"~"dairy"]
> >>
> (45.70234306798271,5.8831787109375,47.864773955792245,10.590820312499998);
> >> out meta;
> >>
> >>  way["shop"~"dairy"]
> >>
> (45.70234306798271,5.8831787109375,47.864773955792245,10.590820312499998);
> >> out meta center qt;
> >>
> >> Pierre
> >>
> >> ________________________________
> >> De : Stefan Keller <sfkeller at gmail.com>
> >> À : Talk Openstreetmap <talk at openstreetmap.org>
> >> Cc : Roland Olbricht <roland.olbricht at gmx.de>
> >> Envoyé le : Jeudi 24 juillet 2014 8h19
> >> Objet : [OSM-talk] Overpass API / Overpass QL: center (and centroid)
> >> function?
> >>
> >> Hi,
> >>
> >> I'm trying to get a list of point features only (as GeoJSON or XML).
> >> This could serve as input e.g. to uMap. The problem is that the query
> >> returns points but also areas. This is actually correct - but I want
> >> these areas converted to point geometries too (centered, like
> >> ST_Centroid).
> >>
> >> I then found the modifcator/keyword "center" in the Overpass QL [1].
> >> But I still get polygons. See the query [2] below.
> >>
> >> Any ideas?
> >>
> >> --Stefan
> >>
> >>
> >> [1] http://wiki.openstreetmap.org/wiki/Overpass_API/Overpass_QL
> >>
> >> [2] http://overpass-turbo.osm.ch/ oder http://overpass-turbo.eu/
> >>
> >> *** Dairy (Käserei) Query ways/areas only... ***
> >>
> >> [out:json]
> >> [timeout:25]
> >> ;
> >> (
> >>  node["shop"~"dairy"]
> >>
> >>
> (45.70234306798271,5.8831787109375,47.864773955792245,10.590820312499998);
> >>  way["shop"~"dairy"]
> >>
> >>
> (45.70234306798271,5.8831787109375,47.864773955792245,10.590820312499998);
> >> );
> >> out meta center qt;
> >>>;
> >> out meta center qt;
> >>
> >> _______________________________________________
> >> talk mailing list
> >> talk at openstreetmap.org
> >> https://lists.openstreetmap.org/listinfo/talk
> >>
> >>
> >
> >
>
> _______________________________________________
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> talk at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/talk
>



-- 
Christian Quest - OpenStreetMap France
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