Re: [postgis-users] TopologyException and ST_Intersection
On Mon, Jun 25, 2012 at 07:23:33PM -0400, jdmorgan wrote: Hi Sandro, Thanks for your reply. Here is the PostGIS version we are using: POSTGIS=1.5.3 GEOS=3.3.1-CAPI-1.7.1 PROJ=Rel. 4.7.1, 23 September 2009 LIBXML=2.7.6 USE_STATS Is it easy to upgrade the GEOS or the POSTGIS version for that matter? What I mean is it an inplace upgrade? We are running on a LINUX server (CENTOS). Inplace upgrade of GEOS is straightforward: just grab 3.3.5, unpack, build and install. --strk; Sent from our free software http://www.gnu.org/philosophy/free-sw.html ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] TopologyException and ST_Intersection
Hi, Check the validity of input geometries with st_isValid() and st_isValidReason() and if invalid objects are found, you can correct them using st_makeValid() Nicolas On 25 June 2012 03:18, Derek Morgan jdmor...@unca.edu wrote: I am attempting to get the area of intersection between to vector polygon tables in PostGIS. I am using the following SQL: SELECT ctys.fips, Sum(ST_Area(ST_Intersection(ctys.the_geom,pads.the_geom))) FROM counties4269 ctys, padus4269 pads WHERE ST_Overlaps(ctys.the_geom, pads.the_geom) GROUP by ctys.fips; However, my query returns the following error: TopologyException: side location conflict at 1.66342e+06 1.99261e+06 ERROR: GEOS overlaps() threw an error! I am guessing that this has to do with some topology issues. Any help or pointers would be greatly appreciated. Thanks, Derek ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] TopologyException and ST_Intersection
Hi Nicolas, This is great. However, we are running POSTGIS=1.5.3 Is this possible in this version? If not, is there a workaround as I don't think we will be able to upgrade that quickely? Thanks, Derek ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] TopologyException and ST_Intersection
Hi Nicolas, This is great. However, we are running POSTGIS=1.5.3 Is this possible in this version? If not, is there a workaround as I don't think we will be able to upgrade that quickely? Hi Derek Yes indeed, there is a trick on postgis 2.0 to clean polygons: try using st_buffer(geom, 0.0). This method is often able to rebuild a valid polygon from an invalid one. I also saw on the list (and tested myself) that st_buffer(st_buffer(geom, -1), 1) could clean some polygons that are not cleaned with only a 0 unit buffer. Nicolas ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] TopologyException and ST_Intersection
People should be cautioned that some polygons might disappear when using a buffer of 0. Does Postgis 2.0 have this problem with makevalid? On Jun 25, 2012 7:47 AM, Nicolas Ribot nicolas.ri...@gmail.com wrote: Hi Nicolas, This is great. However, we are running POSTGIS=1.5.3 Is this possible in this version? If not, is there a workaround as I don't think we will be able to upgrade that quickely? Hi Derek Yes indeed, there is a trick on postgis 2.0 to clean polygons: try using st_buffer(geom, 0.0). This method is often able to rebuild a valid polygon from an invalid one. I also saw on the list (and tested myself) that st_buffer(st_buffer(geom, -1), 1) could clean some polygons that are not cleaned with only a 0 unit buffer. Nicolas ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] TopologyException and ST_Intersection
Nicolas, This is awesome feedback and I really appreciate it as I am new to PostGIS. However, I still get the following after creating new populated tables via the st_buffer(geom, 0.0) or the st_buffer(st_buffer(geom, -1), 1). Any other ideas? NOTICE: TopologyException: side location conflict at 1.66342e+06 1.99261e+06 ERROR: GEOS overlaps() threw an error! Cheers, Derek ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] TopologyException and ST_Intersection
On Mon, Jun 25, 2012 at 09:15:21AM -0700, Bob and Deb wrote: People should be cautioned that some polygons might disappear when using a buffer of 0. Does Postgis 2.0 have this problem with makevalid? No, ST_MakeValid retains all vertices. --strk; Sent from our free software http://www.gnu.org/philosophy/free-sw.html ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] TopologyException and ST_Intersection
On Mon, Jun 25, 2012 at 01:47:22PM -0400, jdmorgan wrote: This is awesome feedback and I really appreciate it as I am new to PostGIS. However, I still get the following after creating new populated tables via the st_buffer(geom, 0.0) or the st_buffer(st_buffer(geom, -1), 1). Any other ideas? NOTICE: TopologyException: side location conflict at 1.66342e+06 1.99261e+06 ERROR: GEOS overlaps() threw an error! Which version of GEOS do you have ? SELECT postgis_full_version(); Try upgrading to latest (3.3.5) If it still fails consider reducing the input pair till it's small enough to be attached as HEXWKB to a ticket. As a workaround you could try shaking the vertices with something like ST_SnapToGrid (and maybe ST_UnaryUnion on the result to ensure validity on collapse). --strk; Sent from our free software http://www.gnu.org/philosophy/free-sw.html ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
Re: [postgis-users] TopologyException and ST_Intersection
Hi Sandro, Thanks for your reply. Here is the PostGIS version we are using: POSTGIS=1.5.3 GEOS=3.3.1-CAPI-1.7.1 PROJ=Rel. 4.7.1, 23 September 2009 LIBXML=2.7.6 USE_STATS Is it easy to upgrade the GEOS or the POSTGIS version for that matter? What I mean is it an inplace upgrade? We are running on a LINUX server (CENTOS). Cheers, Derek ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
[postgis-users] TopologyException and ST_Intersection
I am attempting to get the area of intersection between to vector polygon tables in PostGIS. I am using the following SQL: SELECT ctys.fips, Sum(ST_Area(ST_Intersection(ctys.the_geom,pads.the_geom))) FROM counties4269 ctys, padus4269 pads WHERE ST_Overlaps(ctys.the_geom, pads.the_geom) GROUP by ctys.fips; However, my query returns the following error: TopologyException: side location conflict at 1.66342e+06 1.99261e+06 ERROR: GEOS overlaps() threw an error! I am guessing that this has to do with some topology issues. Any help or pointers would be greatly appreciated. Thanks, Derek ___ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
