id summary reporter owner description type status priority milestone component version resolution keywords cc 11 intersection - possible Bug mcayland " Dear PostGis Users, we are using PostgreSQL / PostGIS very intensively - at the moment in combination with PG-Routing. Because we are routing on areas, we create somthing like a network on them and intersect this netzwork with some area - properties (e.g. vegetation). While doing this, a very strange behaviour occured: intersection of two lines created a point, which is relative far away from one line. Here the simplified sql - statment: select asText(intersection(b.g, a.g)) as intersection, distance (a.g, intersection(b.g, a.g)) as distance from (select '01020000000200000050E8303FC2E85141B017CFC05A825541000000E0C0E85141000000205C825541'::geometry as g) a, (select 'LINESTRING(4694792.35840419 5638508.89950758,4694793.20840419 5638506.34950758)'::geometry as g) b -> so the distance of point and first line is 0.88 (meters) when I use asText for the first Line: select asText(intersection(b.g, a.g)) as intersection, distance (a.g, intersection(b.g, a.g)) as distance from (select asText('01020000000200000050E8303FC2E85141B017CFC05A825541000000E0C0E85141000000205C825541'::geometry) as g) a, (select 'LINESTRING(4694792.35840419 5638508.89950758,4694793.20840419 5638506.34950758)'::geometry as g) b -> the distance reduces to a very little value (xe-10) - with this I have no problem, because I use some little tollerance - but 0.88 is too much in my case. As a workaround I use allways asText at the moment. Our PostGIS fullVerion is 'POSTGIS='1.3.2' GEOS='3.0.0rc4-CAPI-1.3.3' PROJ='Rel. 4.5.0, 22 Oct 2006' USE_STATS' on 'PostgreSQL 8.2.4 on i686-pc-mingw32, compiled by GCC gcc.exe (GCC) 3.4.2 (mingw-special)' By the way - the same Statment in 'POSTGIS='1.2.0' GEOS='2.2.3-CAPI-1.1.1' PROJ='Rel. 4.5.0, 22 Oct 2006' USE_STATS' on 'PostgreSQL 8.2.0 on i686-pc-mingw32, compiled by GCC gcc.exe (GCC) 3.4.2 (mingw-special)' creates a point with a small distance (but >0) in both cases Greetings Thomas and Rene " defect closed medium postgis wontfix