Michael,
you won't find much support for that in GDAL itself. You'd better have a
look at Spatialite topology, PostGIS topology or GRASS topology. The
process is basically: import your geometries as a topology, do
reprojection or other work in the topology domain, and go back to the
geometry domain.
QGIS has a plugin to work with PostGIS topology:
https://plugins.qgis.org/plugins/pgtopoeditor/
(I was involved in discussions yeaaars ago about having GDAL offering a
generic API and translation between all those topology formats but that
never materialized)
Even
Le 09/10/2023 à 21:55, Michael Sumner via gdal-dev a écrit :
Are there any formats that record "coverage" topology? What I'm
worried about is when shapes are encoded as blob geometry with
initially identical coordinates at shared vertices, is there any
process that can validate or record that particular coords should have
the same values even after reprojection or decomposition/rebuild?
I know how to do this in custom ways, I'm hoping to find some
off-the-shelf process to at least refer to (I'm a bit pressed for time
so I'm asking without doing the extra homework that's needed). I
would build an indexer of the unique coordinates and how they relate
to the blob geometries before and after and do checks there, but I
don't know of an existing process that guarantees this.
I understand that precision-setting is used to prevent numeric loss,
but is there any formalization about that loss? (i.e. different
instances of a vertex really do stay unique). I guess the result is
going to be pretty good if you choose the precision appropriately and
modifications aren't extreme?
Thanks for consideration!
Cheers, Mike
--
Michael Sumner
Software and Database Engineer
Australian Antarctic Division
Hobart, Australia
e-mail: mdsum...@gmail.com
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http://www.spatialys.com
My software is free, but my time generally not.
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