[postgis-users] create holes in ocean polygons with island polygons

paul.malm at lfv.se paul.malm at lfv.se
Tue Aug 20 06:34:59 PDT 2019

I have a table with ocean polygons and would like to create holes in those polygons with an island layer (including island polygons).
I've tried this:

UPDATE public."Ocean"
SET the_geom = ST_Multi(ST_Difference("Ocean".the_geom, b.the_geom))
FROM "Islands" as b
WHERE ST_Intersects( "Ocean ".the_geom,  b.the_geom)
Postgresql reports  5 uppdates.
But there are no holes in the ocean polygons, in the location of the islands.

What are I'm doing wrong?

Kind regards,
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