[postgis-users] multipolygon polygon test intersects

[Nicolas Ribot]

> Hi all,
>
> How would I test if a given polygon intersects with one of the polygons
> currently in a multypolygon geometry?
>
> I tried the && operator but if I'm not mistaken it will test the given
> polygon against the bounding box of the whole multipolygon geometry and
> not each one individually.
>
> Thanx in advance.
>

Hi,

I think you will have to explode your multipolyons into single
polygons to do that.
A multipolygon is considered by postgis as a single object, thus &&
and overlaps (or other operators) will work on all polygons composing
the multi.

You can use dump() to generate polygons out of multipolygon, then test
each individual polygon.

HTH
Nicolas