[postgis-devel] ST_Rescale vs. ST_Resize

Sandro Santilli strk at keybit.net
Fri Jul 11 09:04:53 PDT 2014

On Tue, Jul 01, 2014 at 10:25:43AM -0700, Bborie Park wrote:
> ST_Resize and ST_Rescale may give different answers as they're operating on
> two different components of the raster. ST_Resize uses the desired output
> width/height to determine the output scaleX/scaleY. ST_Resample uses the
> desired scaleX/scaleY to determine the output width/height.

The version of ST_Resize I used expresses the new size in term
of fraction of the original size. It's the flavor taking floats
rather than integer. So basically it's supposedly the same as asking
it to "rescale" it. 

ST_Resample has nothing to do with this. I'm referring to:

 ST_Resize:  http://postgis.net/docs/RT_ST_Resize.html
 ST_Rescale: http://postgis.net/docs/RT_ST_Rescale.html

Documentation is not very complete about them:

I've filed the topology corruption here:

> As for the tile to tile gap, I seem to recall that robe experienced a
> similar issue several years ago. I'll see if I can test a simple dataset.

Did you have a chance to test it ?


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