[postgis-devel] Call for 1.4.2 and 1.5.1 (Handling of Invalid Geometries)

[strk]

On Wed, Feb 17, 2010 at 03:35:08PM -0800, Martin Davis wrote:
> Well, so it's still invalid.  So what?  Bottom line is that someone 
> handed in garbage claiming it was a LinearRing.  They can't complain 
> about being told that no, it's actually garbage.
> 
> The idea is to allow more cases to enter the database in a graceful way, 
> without requiring a huge effort to check for bad structure throughout 
> the codebase.  There's no promise to perform magic.  There will always 
> be geometries which are so badly munged that they can't be made valid no 
> matter what.

That's why we want to hold them. Only the user can "cure" them.
Note that the "huge effort" required to check for bad structure throughout
the code base is the same also required to check for NOT PRODUCING
bad structures. That's to say, as we have code that can produce invalid
topologies (ST_ShiftLongitude to cite one) we may as well have other
code which can produce *structurally* invalid ones.

ST_RemovePoint ?
ST_RemoveDuplicatePoints ? 

Yes, you can still call them bugs, but this doesn't prevent that
from happening and thus you'd be with your data *locked* in postgis
and you just can't help !

--strk; 

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