tommy408 ha scritto:
> I'm running a query that test a line if it crosses any polygon in a table,
> and if it doesn't I keep it. And it test 2600 lines.
>
> In postgres with postgis I run this query 2600 times ( different lines)
> which takes 300 milliseconds:
>
> PERFORM gid from terrains where ST_Crosses(v_line , the_geom) limit 1;
> IF NOT FOUND THEN
> // then keep
> END IF;
>
>
> With geotools I run this code for the same purpose which takes 1922
> milliseconds:
>
> Filter intersectFilter = CQL.toFilter("CROSS(the_geom, " + lineString +
> ")");
> Filter bboxFilter = ff.bbox(ff.property( "the_geom" ), envelope );
> Filter andFilter = ff.and(bboxFilter ,intersectFilter);
> FeatureCollection<SimpleFeatureType, SimpleFeature> collection =
> terrainPolygonSource.getFeatures( andFilter);
>
> if ( collection.size() == 0)
> // then keep lineString
>
> What am I doing wrong here? And I already loaded those geometries into
> memory. I only run the time test for this portion of the code. Is this the
> best I can get?
How did you load stuff into memory?
Anyways, if it's really in memory you're not using a spatial index,
that is why postgres is faster. You'll have to restructure your code
to create an use a JTS STRTree. However, for 2 seconds runtime,
it's probably not worth it (it has an up-front creation cost that
you have to factor in).
Cheers
Andrea
--
Andrea Aime
OpenGeo - http://opengeo.org
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