[postgis-users] Point, Polygon - Does not intersects

[Andreas Forø Tollefsen]

I meant take the two geometries into QGIS.


2014-02-17 11:49 GMT+01:00 Andreas Forø Tollefsen <andreasft at gmail.com>:

> Hi,
>
> I am running the current setup:
>  "POSTGIS="2.0.2 r10789" GEOS="3.4.0dev-CAPI-1.8.0" PROJ="Rel. 4.7.1, 23
> September 2009" GDAL="GDAL 1.9.0, released 2011/12/29" LIBXML="2.7.8" (core
> procs from "2.0.1 r9979" need upgrade) RASTER (raster procs from "2.0.1
> r9979" need upgrade)"
>
> I have two tables with geometries. Both include polygons representing
> administrative units. One at the first level and one at the second level.
> I want a table that includes all the second level polygons where
> available, and where not available I want the first level polygons.
>
> To find the level 1 polygons for filling the gaps where level 2 is N/A, I
> thought about finding where the centroid of level one polygons does not
> intersects with the polygons for level 2.
>
> Hence, I tried:
>
> SELECT g1.name, g1.geom INTO gadm2_level1_union_selected FROM
> gadm2_level1_union g1, gadm2_level2_union g2 WHERE
> ST_Intersects(g1.centroid, g2.geom)=FALSE;
>
> I also tried the ST_Disjoint(g1.centroid, g2.geom).
>
> My problem is that this is running for ages without finishing. This should
> be such a simple query, but I have used half of the day running it. If I
> take the two geometries into PostGIS and run a spatial query to find the
> points from level 1 not intersecting with polygons of level 2, it takes 15
> seconds.
>
> What could be the issue with my query?
>
> Thanks!
> Andreas
>
>
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