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

Pierre Béland pierzenh at yahoo.fr
Thu Jul 24 13:48:21 UTC 2014


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;
>
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>
>
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