[postgis-devel] Cube Indexes

Mark Cave-Ayland mark.cave-ayland at ilande.co.uk
Tue Aug 29 06:57:06 PDT 2006


On Tue, 2006-08-15 at 13:37 +0200, Markus Schaber wrote:

(cut)

> The dimension element is redundant.
> 
> If we use floats, dim=(size-4)/4 and size=(4*dim)+4, for doubles it is
> dim=(size-4)/8 and size=(8*dim)+4.
> 
> For doubles, it may be better to pad to 64 bit offsets on most
> platforms, and thus keeping the second unsigned int, however.
> 
> HTH,
> Markus


Hi Markus,

Yeah I did consider this at one point, but thought I had come up with a
reason late one night to show that it wouldn't work when trying to cast
between BOX3Ds/Geometries... however at the moment I can't see a
problem, assuming that all of the coordinates are the same size (which
should be guaranteed in PostGIS).


Kind regards,

Mark.





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