[OSM-talk] OSM Wikidata SPARQL service updated

Yuri Astrakhan yuriastrakhan at gmail.com
Mon Aug 14 15:10:39 UTC 2017

mmd, the centroids are calculated with this code, let me know if there is a
better way, I wasn't aware of any issues with the minute data updates.
      wkb = wkbfab.create_linestring(obj)
      point = loads(wkb, hex=True).representative_point()

Your query is correct, and you are right that (in theory) there shouldn't
be any ways without the center point. But there has been a number of ways
with only 1 point, causing a parsing error "need at least two points for
linestring". I will need to add some special handling for that

You can see the error by adding this line:
   OPTIONAL { ?osmId osmm:loc:error ?err . }
The whole query --  http://tinyurl.com/ydf4qd62  (you can create short urls
with a button on the left side)

On Mon, Aug 14, 2017 at 5:18 AM, mmd <mmd.osm at gmail.com> wrote:

> Hi,
> Am 13.08.2017 um 19:49 schrieb Yuri Astrakhan:
> > * all ways now store "osmm:loc" with centroid coordinates, making it
> > possible to crudely filter ways by location
> out of curiosity, can you say a few words on how your overall approach
> to calculate centroids for ways? As we all know it's an endless pain to
> get that information out of minutely diffs :)
> I have to say that I'm pretty much unfamiliar with SPARQL and just tried
> the following query. My expectation was that I won't get any results,
> making me wonder if my query has some issue?
>   ?osmId osmm:type 'w' .
>   FILTER NOT EXISTS { ?osmId osmm:loc ?osmLoc }.
> } LIMIT 100
> BTW: A quick search on Github yielded the following:
> https://github.com/nyurik/osm2rdf. Would that be the right place to look
> for more details?
> Best,
> mmd
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