Yes, we use on that server very old PostGIS.
"POSTGIS="1.1.6" GEOS="2.2.3-CAPI-1.1.1" PROJ="Rel. 4.6.0, 21 Dec 2007"
USE_STATS"
The most important reason to repair these geometries is that we want to upgrade
to PostgreSQL 8.3 and current PostGIS. According to my tests, it is impossible
to dump back these invalid geometries to newer PostgreSQL/PostGIS environment.
Maybe Geos 3.x is refusing them. I do not know now.
And Yes, You are right, in current version of PostGIS Your function will return
correct geometry. In our old PostGIS (1.1.6), the result is blank.
Ivan
On Wednesday 25 March 2009, Obe, Regina wrote:
> Ivan,
>
> Which version of PostGIS are you running?
>
> Do a:
>
> SELECT postgis_full_version();
>
> to have it return.
>
> When I run your below query, it returns a polygon that looks like this
>
> POLYGON((-266469.87 -1233431.41,-266423.25 -1233425.84,-266423.23
> -1233426.17,-266422.74 -1233434.54,-266422.75 -1233439.44,-266425.68
> -1233439.9,-266457.02 -1233444.89,-266463.17 -1233437.07,-266463.27
> -1233436.29,-266469.15 -1233437.08,-266469.84 -1233431.65,-266469.87
> -1233431.41),(-266463.92 -1233431.02,-266463.01 -1233431.01,-266463
> -1233431,-266463.92 -1233431.02),(-266459.41 -1233430.46,-266458.67
> -1233436.67,-266451.29 -1233435.76,-266451.1 -1233437.26,-266438.9
> -1233435.75,-266439.07 -1233434.35,-266426.37 -1233432.65,-266427.07
> -1233426.46,-266439.85 -1233428.04,-266459.41 -1233430.46))
>
> Although if your table requires multipolygons which I suspect it does, you'll
> want to wrap in a ST_Multi like
>
> SELECT AsText(ST_Multi(BuildArea(Collect(b.final_geom)))) as filtered_geom
> FROM (SELECT MakePolygon((/* Get outer ring of polygon */
> SELECT ExteriorRing(a.the_geom) as outer_ring /* ie
> the outer ring */
> ), ARRAY(/* Get all inner rings > a particular area */
> SELECT ExteriorRing(b.geom) as inner_ring
> FROM (SELECT (DumpRings(a.the_geom)).*) b
> WHERE b.path[1] > 0 /* ie not the outer ring */
> AND (NPoints(b.geom) > 2 AND IsClosed(b.geom))
> ) ) as final_geom
> FROM (SELECT g.geom As the_geom
> FROM Dump(geomFromText('MULTIPOLYGON(((-266469.87
> -1233431.41,-266423.25 -1233425.84,-266423.23 -1233426.17,-266422.74
> -1233434.54,-266422.75 -1233439.44,-266425.68 -1233439.9, -266457.02
> -1233444.89,-266463.17 -1233437.07,-266463.27 -1233436.29,-266469.15
> -1233437.08,-266469.84 -1233431.65,-266469.87 -1233431.41),(-266463.92
> -1233431.02, -266463.00 -1233431.00, -266463.01 -1233431.01,
> -266463.92 -1233431.02), (-266459.41 -1233430.46,-266458.67
> -1233436.67,-266451.29 -1233435.76,-266451.1 -1233437.26,-266438.9
> -1233435.75,-266439.07 -1233434.35,-266426.37 -1233432.65,-266427.07
> -1233426.46, -266439.85 -1233428.04,-266459.41 -1233430.46)))')) As g
> WHERE NPoints(g.geom) > 2 AND IsClosed(g.geom)
> ) As a
> ) As b
>
> Hope that helps,
> Regina
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Ivan
> Mincik
> Sent: Wednesday, March 25, 2009 4:37 AM
> To: PostGIS Users Discussion
> Subject: Re: [postgis-users] reparing invalid geometry (polygon defined
> byoneor two points)
>
> Thanks for Simon's blog, I have found very interesting things there.
> I hope I understand what's going on in that function, but I always get
> empty geometry result.
>
> As test I tried following:
>
> SELECT AsText(BuildArea(Collect(b.final_geom))) as filtered_geom
> FROM (SELECT MakePolygon((/* Get outer ring of polygon */
> SELECT ExteriorRing(a.the_geom) as outer_ring /* ie
> the outer ring */
> ), ARRAY(/* Get all inner rings > a particular area */
> SELECT ExteriorRing(b.geom) as inner_ring
> FROM (SELECT (DumpRings(a.the_geom)).*) b
> WHERE b.path[1] > 0 /* ie not the outer ring */
> AND (NPoints(b.geom) > 2 AND IsClosed(b.geom))
> ) ) as final_geom
> FROM (SELECT g.geom As the_geom
> FROM Dump(geomFromText('MULTIPOLYGON(((-266469.87
> -1233431.41,-266423.25 -1233425.84,-266423.23 -1233426.17,-266422.74
> -1233434.54,-266422.75 -1233439.44,-266425.68 -1233439.9, -266457.02
> -1233444.89,-266463.17 -1233437.07,-266463.27 -1233436.29,-266469.15
> -1233437.08,-266469.84 -1233431.65,-266469.87 -1233431.41),(-266463.92
> -1233431.02, -266463.00 -1233431.00, -266463.01 -1233431.01,
> -266463.92 -1233431.02), (-266459.41 -1233430.46,-266458.67
> -1233436.67,-266451.29 -1233435.76,-266451.1 -1233437.26,-266438.9
> -1233435.75,-266439.07 -1233434.35,-266426.37 -1233432.65,-266427.07
> -1233426.46, -266439.85 -1233428.04,-266459.41 -1233430.46)))')) As g
> WHERE NPoints(g.geom) > 2 AND IsClosed(g.geom)
> ) a
> ) b
>
> Result is empty geometry. After removing both IsClosed conditions
> geometry will appear. Why ? Where can be mistake ?
>
> Ivan
>
>
>
> On Tue, Mar 24, 2009 at 1:24 PM, Obe, Regina <[email protected]>
> wrote:
> > Ivan,
> >
> > Oops more of a variant. I see you have invalid polygons as well not
> > just rings. Hmm try this instead. I didn't check my logic, but
> > hopefully you get the idea if this doesn't compile.
> >
> > This is a bit of overkill if you have no multipolys with invalid rings.
> > But I'll leave as an exercise for you to figure out the simpler variant
> > if you need it.
> >
> > CREATE OR REPLACE FUNCTION remove_invalidpoly(geometry)
> > RETURNS geometry AS
> > $BODY$
> > SELECT ST_BuildArea(ST_Collect(b.final_geom)) as filtered_geom
> > FROM (SELECT ST_MakePolygon((/* Get outer ring of polygon */
> > SELECT ST_ExteriorRing(a.the_geom) as outer_ring /* ie
> > the outer ring */
> > ), ARRAY(/* Get all inner rings > a particular area */
> > SELECT ST_ExteriorRing(b.geom) as inner_ring
> > FROM (SELECT (ST_DumpRings(a.the_geom)).*) b
> > WHERE b.path[1] > 0 /* ie not the outer ring */
> > AND (ST_NPoints(b.geom) > 2 AND ST_IsClosed(b.geom))
> > ) ) as final_geom
> > FROM (SELECT g.geom As the_geom
> > FROM ST_Dump($1) As g
> > WHERE ST_NPoint(g.geom) > 2 AND ST_IsClosed(g.geom)
> > ) a
> > ) b
> > $BODY$
> > LANGUAGE 'sql' IMMUTABLE;
> >
> >
> > -----Original Message-----
> > From: [email protected]
> > [mailto:[email protected]] On Behalf Of Obe,
> > Regina
> > Sent: Tuesday, March 24, 2009 8:14 AM
> > To: PostGIS Users Discussion
> > Subject: RE: [postgis-users] reparing invalid geometry (polygon defined
> > byoneor two points)
> >
> > Ivan,
> >
> > I think a variant of Simon's script would work for you except instead of
> > keeping rings with a large enough hole, keep rings that are closed and
> > have enough points
> >
> > http://www.spatialdbadvisor.com/postgis_tips_tricks/92/filtering-rings-i
> > n-polygon-postgis
> >
> > so something like
> >
> > CREATE OR REPLACE FUNCTION remove_invalidrings(geometry)
> > RETURNS geometry AS
> > $BODY$
> > SELECT ST_BuildArea(ST_Collect(b.final_geom)) as filtered_geom
> > FROM (SELECT ST_MakePolygon((/* Get outer ring of polygon */
> > SELECT ST_ExteriorRing(a.the_geom) as outer_ring /* ie
> > the outer ring */
> > ), ARRAY(/* Get all inner rings > a particular area */
> > SELECT ST_ExteriorRing(b.geom) as inner_ring
> > FROM (SELECT (ST_DumpRings(a.the_geom)).*) b
> > WHERE b.path[1] > 0 /* ie not the outer ring */
> > AND (ST_NPoints(b.geom) > 2 AND ST_IsClosed(b.geom))
> > ) ) as final_geom
> > FROM (SELECT ST_GeometryN(ST_Multi($1),/*ST_Multi converts any
> > Single Polygons to MultiPolygons */
> >
> > generate_series(1,ST_NumGeometries(ST_Multi($1)))
> > ) as the_geom
> > ) a
> > ) b
> > $BODY$
> > LANGUAGE 'sql' IMMUTABLE;
> >
> > Hope that helps,
> > Regina
> >
> >
> >
> > -----Original Message-----
> > From: [email protected]
> > [mailto:[email protected]] On Behalf Of Ivan
> > Mincik
> > Sent: Tuesday, March 24, 2009 5:03 AM
> > To: PostGIS Users Discussion
> > Subject: [postgis-users] reparing invalid geometry (polygon defined by
> > oneor two points)
> >
> > Dear PostGIS users,
> > we have quite huge MULTIPOLYGON database table containing some 3
> > percents of invalid geometries.
> > Most problematic to repair are MULTIPOLYGONs which often contain polygon
> > defined by one or two points.
> >
> > Example is here (second polygon is defined by one point):
> > MULTIPOLYGON(((-266469.87 -1233431.41,-266423.25 -1233425.84,-266423.23
> > -1233426.17,-266422.74 -1233434.54,-266422.75 -1233439.44,-266425.68
> > -1233439.9,
> > -266457.02 -1233444.89,-266463.17 -1233437.07,-266463.27
> > -1233436.29,-266469.15 -1233437.08,-266469.84 -1233431.65,-266469.87
> > -1233431.41),(-266463.92 -1233431.02),
> > (-266459.41 -1233430.46,-266458.67 -1233436.67,-266451.29
> > -1233435.76,-266451.1 -1233437.26,-266438.9 -1233435.75,-266439.07
> > -1233434.35,-266426.37 -1233432.65,-266427.07 -1233426.46,
> > -266439.85 -1233428.04,-266459.41 -1233430.46)))
> >
> > It is not possible to run buffer(0) or many other functions on these
> > geometries because of "POSTGIS2GEOS conversion failed" (no suprise in
> > case of such non-sense geometry).
> >
> > Is there any possibility how to repair them directly in database?
> >
> >
> > Thanks
> > Ivan
> >
> > _______________________________________________
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> confidential, legally privileged and/or exempt from disclosure
> pursuant to Massachusetts law. It is intended
> solely for the addressee. If you received this in error, please
> contact the sender and delete the material from any computer.
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