I am trying to do some processing on some very large polygon layers. However I am running into various geometry errors such as:
NOTICE: Ring Self-intersection at or near point 470396.52017068537 141300.52235257279
CONTEXT: PL/pgSQL function st_intersection(geometry,raster,integer) line 10 at RETURN QUERY
SQL function "st_intersection" statement 1
NOTICE: Ring Self-intersection at or near point 504154.61769969884 140782.04115761846
CONTEXT: PL/pgSQL function st_intersection(geometry,raster,integer) line 10 at RETURN QUERY
SQL function "st_intersection" statement 1
NOTICE: Ring Self-intersection at or near point 505255.50242871145 140803.34860398644
CONTEXT: PL/pgSQL function st_intersection(geometry,raster,integer) line 10 at RETURN QUERY
SQL function "st_intersection" statement 1
NOTICE: Ring Self-intersection at or near point 510312.46970004693 141215.29256710084
CONTEXT: PL/pgSQL function st_intersection(geometry,raster,integer) line 10 at RETURN QUERY
SQL function "st_intersection" statement 1
NOTICE: Ring Self-intersection at or near point 510312.46970004693 141215.29256710084
CONTEXT: PL/pgSQL function st_intersection(geometry,raster,integer) line 10 at RETURN QUERY
SQL function "st_intersection" statement 1
NOTICE: Ring Self-intersection at or near point 511839.50335641927 141115.85781738357
CONTEXT: PL/pgSQL function st_intersection(geometry,raster,integer) line 10 at RETURN QUERY
SQL function "st_intersection" statement 1
NOTICE: Ring Self-intersection at or near point 515064.03024010791 140895.68087158105
CONTEXT: PL/pgSQL function st_intersection(geometry,raster,integer) line 10 at RETURN QUERY
SQL function "st_intersection" statement 1
NOTICE: Ring Self-intersection at or near point 519233.18724611058 140881.47590733573
CONTEXT: PL/pgSQL function st_intersection(geometry,raster,integer) line 10 at RETURN QUERY
SQL function "st_intersection" statement 1
NOTICE: Ring Self-intersection at or near point 521072.73011588014 141044.83299615697
CONTEXT: PL/pgSQL function st_intersection(geometry,raster,integer) line 10 at RETURN QUERY
SQL function "st_intersection" statement 1
NOTICE: Ring Self-intersection at or near point 523331.31943088671 141144.26774587421
CONTEXT: PL/pgSQL function st_intersection(geometry,raster,integer) line 10 at RETURN QUERY
SQL function "st_intersection" statement 1
NOTICE: Ring Self-intersection at or near point 523331.31943088671 141144.26774587424
CONTEXT: PL/pgSQL function st_intersection(geometry,raster,integer) line 10 at RETURN QUERY
SQL function "st_intersection" statement 1
NOTICE: Ring Self-intersection at or near point 523395.24176999065 140725.22130063715
CONTEXT: PL/pgSQL function st_intersection(geometry,raster,integer) line 10 at RETURN QUERY
SQL function "st_intersection" statement 1
NOTICE: Ring Self-intersection at or near point 524531.63890961662 140810.45108610913
CONTEXT: PL/pgSQL function st_intersection(geometry,raster,integer) line 10 at RETURN QUERY
SQL function "st_intersection" statement 1
I have tried the function suggested here: https://trac.osgeo.org/postgis/wiki/UsersWikiCleanPolygons
for cleaning geometries, the code I have used being:
UPDATE public.mytable
SET geom=cleangeometry(geom);
With the result:
ERROR: GEOSisSimple: IllegalArgumentException: This method does not support GeometryCollection arguments
and also
UPDATE public.valid_mytable
SET geom=ST_MakeValid(geom);
This one works, but only if I first change my geometry column to geometry
ALTER TABLE public.mytable ALTER COLUMN geom SET DATA TYPE geometry;
Which then leaves me with a table that no longer works with my other functions!
ERROR: Relate Operation called with a LWGEOMCOLLECTION type. This is unsupported.
I have tried changing the columns back to geometry(MultiPolygon)
ALTER TABLE public.my_table ALTER COLUMN geom SET DATA TYPE geometry(MultiPolygon);
But this fails
ERROR: Geometry type (GeometryCollection) does not match column type (MultiPolygon)
I have tried going through PostGIS in Action (Second Ed) http://www.manning.com/obe/ but I can only find functions for finding invalid geometries, but my data-set is so big to fix this manually, I really need something that will fix them automatically.
I have been able to isolate the problem polygons, when I try and run ST_MakeValid() I get the result:
ERROR: Geometry type (GeometryCollection) does not match column type (MultiPolygon)
********** Error **********
ERROR: Geometry type (GeometryCollection) does not match column type (MultiPolygon)
SQL state: 22023
I did a type check on my geometry column, and it said the type was "MULTIPOLYGON"