[OSM-dev] [OverpassAPI] Distinguish request matching features and referenced content ?

[Martin Raifer]

There are several ways to accomplish a kind of separation between the
"matched" content and the "referenced" (geometry containing) objects.
The most basic one would be to simply divide the query into two: First
only outputting the matched content, and second outputting referenced
objects. This has the downside of putting more load on the Overpass
server than what is actually needed. A better solution would be to
output the referenced content without any tags (by using `out skel;`
after the recurse-down – see overpass-turbo's wizard how this can be
done): Then you can distinguish between the main "information objects"
which have tags and the "geometry-providing" referenced stuff which
doesn't have any tags on them. This approach also reduces network
traffic, as fewer tags means less bytes to be transferred.

Martin

On Sun, Sep 27, 2015 at 7:02 PM, François Lacombe
<fl.infosreseaux at gmail.com> wrote:
> Hi all,
>
> I'm currently trying to import some features from OSM a in a DB by
> using several Overpass queries.
>
> As for loading any referenced content (nodes in ways, members in
> relations), those requests contain "(._;>;);" statement.
>
> I'm not able so far to distinguish the request matching content and
> the referenced content since all is coming between <osm> markups.
>
> My logic dealing with requests results is also trying to convert
> referenced nodes and members the same way as the request matching
> content since the logic doesn't know which is request matching or not.
>
> Should I improve my logic or get a cool way to obtain the output below ?
> In this example, only the way is matching request statements, nodes
> are part of the way.
> <osm>
>   <way id="xxxxx" ... >
>     <nd ref="yyyyy"/>
>     <nd ref="zzzzz"/>
>   </way>
>
>   <reference>
>      <node id="yyyyy"/>
>      <node id="zzzzz"/>
>   </reference>
> </osm>
>
> The processing logic would only deal with the way and ignore the nodes.
>
> Many thanks in advance for any help, all the best,
>
>
> François Lacombe
>
> fl dot infosreseaux At gmail dot com
> www.infos-reseaux.com
> @InfosReseaux
>
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