[postgis-users] ST_CreateTopoGeo

[Sandro Santilli]

On Fri, Feb 28, 2020 at 12:29:49PM +0000, paul.malm at lfv.se wrote:
> Hi again,
> I can see in the edge data of topo2 that the main polygon of Egypt intersects with an island next to the main polygon. If I delete the island in the original layer before running the SQL sequence the main polygon of Egypt is included in the result layer. Is there any solution of this problem?

The above (being unable to include Egypt when island is added) still
depends on the tolerance value, right ? There's probably a spatial
configuration between those 2 polygons that triggers an excessive
snapping with high tolerances. Keep your tolerances low!

Or, insert the island in the topology as the last thing, and see
where the error ends up being (the whole point of building the
topology incrementally rather than in a single step is to be able
to deal with each case separately, and spot what's special about it)

--strk;