[OSM-dev] XML xPath or trick to get way bounds

François Lacombe fl.infosreseaux at gmail.com
Sun Apr 30 00:09:37 UTC 2017


Hi Imre,

Thank you for this answer :)

The first item with Oapi is great, I wasn't aware it was possible to ask
for such information.
All the data I process is get from OApi and queries have to be adapted a
bit to work as expected

I'm not so familiar with osmtogeojson or osmium-tool but it can be useful
too.


Have a nice weekend, all the best

François


*François Lacombe*

fl dot infosreseaux At gmail dot com
www.infos-reseaux.com
@InfosReseaux <http://www.twitter.com/InfosReseaux>

2017-04-24 17:34 GMT+02:00 Imre Samu <pella.samu at gmail.com>:

> >With osm xml format (overpass, josm), is there any technique to get the
> bounds of a given way ?
> >I want to get min lat/lng and max lat/lng without processing the whole
> document (which can be pretty big)
> > ... Thanks in advance for any hint
>
> I am not sure if I understood your problem correctly,  but there are some
> interesting  *extended osm xml formats with geometries.*
>
> *Overpass API* [1] has a different XML outputs:
> * "out geom" : Add the full geometry to each object."
> * "out bb"      : Adds only the bounding box of each element to the
> element."
> * "out center": This adds only the center of the above mentioned bounding
> box to ways and relations."
> [1] https://wiki.openstreetmap.org/wiki/Overpass_API/Overpass_
> QL#Print_.28out.29
>
> so this query http://overpass-turbo.eu/s/oA4    " way(24710885);   out
> geom; "
> calculate the bb + add geometries for the nodes;
>
>   <way id="24710885">
>     *<bounds minlat="47.5082028" minlon="19.0240336" maxlat="47.5084101"
> maxlon="19.0268190"/>*
>     <nd ref="268581277" lat="47.5082713" lon="19.0268190"/>
>     <nd ref="700251685" lat="47.5082049" lon="19.0265792"/>
>     <nd ref="700251660" lat="47.5082028" lon="19.0265032"/>
>     <nd ref="268583145" lat="47.5082056" lon="19.0264232"/>
>     <nd ref="2859100026" lat="47.5082971" lon="19.0248566"/>
>     <nd ref="3114752087" lat="47.5083150" lon="19.0245494"/>
>     <nd ref="268583146" lat="47.5083293" lon="19.0243048"/>
>     <nd ref="4451395635" lat="47.5084076" lon="19.0240419"/>
>     <nd ref="268583147" lat="47.5084101" lon="19.0240336"/>
>     <tag k="highway" v="residential"/>
>     <tag k="is_in" v="Budapest"/>
>     <tag k="name" v="Retek utca"/>
>     <tag k="oneway" v="yes"/>
>   </way>
>
>
> As I know *osmtogeojson*  [ https://github.com/tyrasd/osmtogeojson ]
> supporting Overpass API's extended geometry output modes.
>
> And  *osmium-tool   *has a similar special command: * "osmium
> add-locations-to-ways " *  to create a "Node Locations on Ways" ,
> so it is easy to calculate the bounding box.
>
> <way id="123"...>
>   <nd ref="12" lon="3.141" lat="5.926"/>
>   <nd ref="13" lon="2.111" lat="1.222"/>
> </way>
>
> more info:
> * https://blog.jochentopf.com/2016-04-20-node-locations-on-ways.html
> * http://docs.osmcode.org/osmium/latest/osmium-add-locations-to-ways.html
>
>
> If the preprocessing is ok, then maybe you can use *"osmium-extract" *
>  to "create geographical extracts from an OSM file"    and drop the
> unwanted nodes ...
> * http://docs.osmcode.org/osmium/latest/osmium-extract.html
> * https://blog.jochentopf.com/2017-02-06-expedicious-and-exa
> ct-extracts-with-osmium.html
>
>
> best,
>  Imre
>
>
> 2017-04-24 8:26 GMT+02:00 François Lacombe <fl.infosreseaux at gmail.com>:
>
>> Hi all,
>>
>> With osm xml format (overpass, josm), is there any technique to get the
>> bounds of a given way ?
>>
>> I want to get min lat/lng and max lat/lng without processing the whole
>> document (which can be pretty big)
>>
>> This would be useful to list all nodes from my db contained into that
>> bounds prior to process ways.
>> I want to prevent numerous queries to check if each individual node
>> exists or not while importing ways, assuming that some nodes already exist
>> and some other don't.
>>
>> The question can be extended to relations if possible
>>
>> Thanks in advance for any hint
>>
>> All the best
>> Francois
>>
>> _______________________________________________
>> dev mailing list
>> dev at openstreetmap.org
>> https://lists.openstreetmap.org/listinfo/dev
>>
>>
>
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