[gdal-dev] format for topology?

[Michael Sumner]

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: mdsumner at gmail.com
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