[geos-devel] [GEOS] #737: TopologyException for Valid geoemtries

[GEOS]

#737: TopologyException for Valid geoemtries
----------------------------+--------------------------
 Reporter:  bladeoflight16  |      Owner:  geos-devel@…
     Type:  defect          |     Status:  new
 Priority:  major           |  Milestone:  3.4.3
Component:  Default         |    Version:  3.4.2
 Severity:  Unassigned      |   Keywords:
----------------------------+--------------------------
 I have 2 supposedly valid geometries. When I try to take the difference
 between them:

 {{{
 WITH geom1 (g) AS
 (VALUES(ST_GeomFromEWKB(DECODE($$AQYAACAjaQAAAwAAAAEDAAAAAQAAAAkAAAB28/KWa9oWQSePXfN2Q1JBqrU4RG7aFkGksIr/f0NS
 QazxLppr2hZBGx9M/nZDUkGh1GSca9oWQffnBv52Q1JBPKwR52vaFkEY6B74dkNSQTbQvkJs2hZB
 3Q0983ZDUkHFuN1EbNoWQVwaKvN2Q1JBgorsxi3bFkH9c+m5dkNSQXbz8pZr2hZBJ49d83ZDUkEB
 AwAAAAEAAAANAAAAKu2ZA3PaFkFrK3ILkENSQXU40QZz2hZBltlQFpBDUkGL2P81BdwWQV8rUp+P
 Q1JBAN7DMgXcFkFPnWOUj0NSQVoEjjAF3BZBT9OolI9DUkFzLuHlBNwWQQjTkJqPQ1JB+gw0igTc
 FkEqrXKfj0NSQWstFYgE3BZBW6CFn49DUkGkWbq1c9oWQVAZHRaQQ1JB1NJmsXPaFkF6uvkVkENS
 QVXR5lJz2hZB8+xOEZBDUkHbKskEc9oWQZUalAuQQ1JBKu2ZA3PaFkFrK3ILkENSQQEDAAAAAQAA
 AAcAAADqJmDJ/dsWQdMPPod2Q1JBvt4oxv3bFkHDYV98dkNSQY2/Pxf92xZBzyGTfHZDUkEbRZMb
 /dsWQZ2Atnx2Q1JBA0UTev3bFkE/TmGBdkNSQaHpMMj92xZBsyAch3ZDUkHqJmDJ/dsWQdMPPod2
 Q1JB$$, 'base64')))),
 geom2 (g) AS
 (VALUES(ST_GeomFromEWKB(DECODE($$AQMAACAjaQAAAQAAABUAAACs/bu0c9oWQZJkHRaQQ1JBLBWdsnPaFkETWDAWkENSQcny71Zz2hZB
 bDISG5BDUkEaHUMMc9oWQWQy+iCQQ1JBOjoNCnPaFkGJaT8hkENSQTBygHN62hZB/7NlLqlDUkHq
 r690etoWQSijhy6pQ1JBQljNwnraFkFtdUI0qUNSQUVbTSF72hZB1ULtOKlDUkEY4qAle9oWQamh
 EDmpQ1JBc2b09wvcFkFWqHjCqENSQfNFE/oL3BZBJbVlwqhDUkHVZcBVDNwWQeXag72oQ1JB0Dlt
 oAzcFkET25u3qENSQVoTo6IM3BZBE6VWt6hDUkE/JDc5BdwWQW3ZMKqPQ1JB6eYHOAXcFkFN6g6q
 j0NSQW1A6ukE3BZB8xdUpI9DUkEAP2qLBNwWQXBKqZ+PQ1JBYrkWhwTcFkGk64Wfj0NSQaz9u7Rz
 2hZBkmQdFpBDUkE=$$, 'base64'))))
 --SELECT ST_IsValidDetail(geom1.g), ST_IsValidDetail(geom2.g)
 SELECT ST_Difference(geom1.g, geom2.g)
 FROM geom1, geom2;
 }}}

 (Sorry for all the nasty base64. I wanted to make sure they come through
 exactly. You can leave the whitespace there in PostgreSQL. {{{DECODE}}}
 strips it out it properly; in fact, {{{ENCODE}}} is what generated it.)

 I get the following error:

 {{{
 ERROR: GEOSDifference: TopologyException: found non-noded intersection
 between LINESTRING (374438 4.78778e+06, 374529 4.78777e+06) and LINESTRING
 (374529 4.78777e+06, 374466 4.78778e+06) at 374526.95988686144
 4787774.5327140652
 SQL state: XX000
 }}}

 You can confirm that they're reported as valid geometries by
 commenting/uncommenting the {{{SELECT}}} lines appropriately.

 Note that the {{{geom1}}} geometry is actually the output from a
 different, successful {{{ST_Difference}}}, so it's not actually valid,
 there's a bug in what it outputs.

 If you pull up the geometries, you'll find this is not squeaky clean data.
 It comes from data that is taken over several years, and for every year, I
 need to figure out what the most current data is. Sometimes the data is
 retaken, so I need to cut out old overlaps but bring in data from new
 locations. I've done a ton of work trying to automatically clean this data
 some, but I still run into these errors all the time. Expect more reports
 as I run into them.

 I assumed this is a GEOS problem based on the error message. If not, I
 will happily report elsewhere.

 Full PostGIS version, if it's of any help or I should look at upgrading
 anything:

 {{{POSTGIS="2.1.4 r12966" GEOS="3.4.2-CAPI-1.8.2 r3921" PROJ="Rel. 4.8.0,
 6 March 2012" GDAL="GDAL 1.9.2, released 2012/10/08" LIBXML="2.7.6"
 LIBJSON="UNKNOWN" TOPOLOGY RASTER}}}

 GEOS is the latest version, in spite of PostGIS being a little bit behind.
 I was trying to reproduce with a newer version of PostGIS, but
 PostgreSQL's apt repository contains an outdated GEOS. I don't have time
 right now to install all that again, but it is worth noting that this
 issue does ''not'' reproduce on GEOS 3.3.3. (Full version of that install
 is {{{POSTGIS="2.1.7 r13414" GEOS="3.3.3-CAPI-1.7.4" PROJ="Rel. 4.7.1, 23
 September 2009" GDAL="GDAL 1.9.0, released 2011/12/29" LIBXML="2.8.0"
 LIBJSON="UNKNOWN" RASTER}}}.)

--
Ticket URL: <https://trac.osgeo.org/geos/ticket/737>
GEOS <http://trac.osgeo.org/geos>
GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS).