[postgis-devel] WKTRaster Scale and Skew

[Pierre Racine]

Hi Frank :-)

>I haven't read over the proposals for ST_Rotation etc in WKTRaster in
>detail, but I hope you will be careful not to muddle things badly.

Hopefully not! We are just trying to make clear that pixelsizex is not really the pixel size in a rotated raster. This have been confusing many people.

>The phrase "so a user can always test if ST_RotationX = ST_RotationY
>and determine himself if it is a true rotation" was pretty damning in
>my opinion.

This pinpoint the fact that there is actually two things rotated: a x component and a y component and that they can be different when the pixel is diamond shaped.

Pierre