[postgis-devel] GBOXF

[Sandro Santilli]

On Wed, Nov 30, 2011 at 12:03:23PM +0000, Mark Cave-Ayland wrote:

> Actually while you mention it, I can also see how GROUP BY could be
> an issue with points in the same way as two points very close
> together could potentially be considered as one.

Right. But I still don't see an issue with it, as it's semantically
the same as two completely different lines having the same bounding
box. It's like 10 being 5+5 but also 4+6.

More concerning were two _equal_ geometries being considered not equal
because the bounding box of one of them was computed using doubles
and the other was rounded to floats:
http://trac.osgeo.org/postgis/ticket/1273

I think the contract here is: bounding box of a geometry is the minimum
bounding box that can enclose a geometry expressible with the given
numeric precision. It's been floats so far (since 1.x ?).

I think this is what we're debating: if it should be floats or doubles.
Having a mix of the two representations scaries me a little bit (see
the bug above).

--strk;

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