[postgis-users] PostGIS Topology Error

Sandro Santilli strk at kbt.io
Wed Jul 4 09:36:55 PDT 2018

On Wed, Jul 04, 2018 at 02:01:19PM +0200, Cameron Green wrote:

> Using the textbook, Mastering PostGIS chapter 8, where it deals with PostGIS Topology. Below is the SQL commands I used. When I used SRID as 4026 and 0,00028 as the snap threshold, the commands execute without any issues. However, when I change the SRID to 2049 and decrease the snap tolerance in the topology.toTopoGeom, I get the following error: 

The query you report uses 5 as the snap tolerance, that'd be
increasing, not decreasing ? Sometime you want a smaller snap
tolerance in order to overcome those kind of errors (snapping
may be over destructive). Also make sure to use latest PostGIS,
and try isolating the geometries that won't get immediately
converted (using a wrapper function) to try them again later,
possibly after some intermediate cleanup.


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