Software gvSIG OA Digital Edition 2010 have tools topology for finding pseudo nodes in linear geometry. I set cluster tolerance 0.00002 and maximum number of errors -10000 for 20000 link count linear geometry. But unsuccessful result. Are there any solutions that find pseudo nodes in free GIS software? I need to layer pseudo nodes (one solution to this problem - to use tools topology of ArcInfo, but priority for me is to use free software). Linear geometry created several users in QGIS 1.8.0 in PostGIS (v. 2.0.1) database.
Add new image: 12 linear features with three pseudo nodes in A (line 4/5), B (line 6/7), C (line 9/10). Pseudo nodes should be points instead - two linear features with intersection in one point (node) should be one linear feature (line 4/5 - line 4, ...). Thanks for the help.
Is it possible to make a request in PostGIS, which will result in a layer of pseudo nodes?
Add new image of examples pseudo nodes: if I receive for linear layer point layer pseudo nodes (blue rects) I corrected following errors in linear layer: A - add missing geometry, B - snapped line in intersection, C - remove pseudo node. Thanks!
Updated 07.12.2012 Q: Is it possible to make a request in PostGIS, which will result in a layer of pseudo nodes?
A: see answer from Peter Krauss
Updated 26.07.2013 Added answer about Topology Checker plugin for QGIS 1.9.0 (2.0)