nice example,
these kind of examples show the power of the persistent topology.
thanks to make it.
On 13/04/2012 14:42, Sandro Santilli wrote:
On Wed, Apr 11, 2012 at 02:59:41PM +0200, Sandro Santilli wrote:
Alternatively you could still construct the topology with full-precision
edges and then simplify the edges in-place (possibly after a CopyTopology),
using ST_ChangeEdgeGeom. That way the _original_ nodes will remain the same
and you'd be only simplifying the edges connecting them. Beware in this
case that simplification might still introduce topology errors but such
errors would be cought by ST_ChangeEdgeGeom with throwing an exception.
You may catch the exception to reduce tolerance for a given edge or bypass
all checks by editing the edge_data table directly and cross your fingers :)
ValidateTopology should then tell you what you broke, if you want to fix
manually after the fact.
FYI, I wrote a blog post showcasing this approach (with code):
http://strk.keybit.net/blog/2012/04/13/simplifying-a-map-layer-using-postgis-topology/
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