[postgis-devel] WKTRaster Scale and Skew
mateusz at loskot.net
Fri Sep 10 16:36:48 PDT 2010
On 10/09/10 17:16, Pierre Racine wrote:
>> Width is computed based on scale & skew?
> In 99% of the cases there is no rotation and pixel width & height ARE
> synonyms for scale X and scale Y.
Have you researched this aspect and collected statistics?
I hope we've agreed to stop betting which use case is more
frequent and which not :-)
> Is it worth changing their names?
I don't tink so.
> How does GDAL name it?
There is know official terminology here, but in documentation
GDAL usually uses pixel width and height.
>> We separate the accessors for the pixel width and the georeference
>> component that is now used as the width.
> You mean creating a "truepixelwidth" function? Same reluctance since
> it is not really a width when the pixel shape is a diamond.
> But you could say "this happen only 0.001 of the time"...
Yet another interesting statistic?
> Does that mean removing or renaming the ST_PixelSizeX and ST_PixelSizeY function?
I personally think there is nothing wrong or confusing in those names.
SizeX is a synonim to width and SizeY of height, also in GDAL.
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org
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