[postgis-users] get the biggest intersection

[Stephen Woodbridge]

Try:

select count(*) from polygons where not isvalid(geometry);

if count > 0 then

select count(*) from polygons where not isvalid(geometry) and not 
isvalid(st_buffer(geometry, 0.0));

you can do an update to fix these:

update polygons set geometry=st_buffer(geometry, 0.0) where not 
isvalid(geometry);


-Steve W

On 6/20/2012 7:54 AM, Denis Rouzaud wrote:
> Hi all,
>
> I have a table of line and a table of polygons. For a given line, I
> would like to get the polygon which has the biggest intersection with
> the line.
> I tried something like this:
>
> CREATE OR REPLACE FUNCTION distribution.get_zone_id(geometry) RETURNS
> integer AS '
>      DECLARE
>          inputgeom ALIAS FOR $1;
>          id_poly integer;
>      BEGIN
>          SELECT id INTO id_poly
>              FROM  polygons
>              WHERE ST_Intersects(inputgeom,geometry) IS TRUE
>              ORDER BY ST_Length(ST_Intersection(inputgeom,geometry)) DESC
>              LIMIT 1;
>          RETURN id_poly;
>      END
> ' LANGUAGE 'plpgsql';
>
> But I have the following error:
> ERROR:  Error performing intersection: TopologyException: side location
> conflict at 553524.92178241001 147945.03792368001
>
> If anyone has any idea, tip or whatever, it is very welcome!
>
> Greetings,
>
> Denis
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