[GRASS-user] clip and rotate a raster

[Hamish]

G. Allegri wrote:
> I don't have a raster that fits my region.

this will do it:
 r.mapcalc 'regionrast = 1'


> The unsolved problem is rotation (and shift): making affine
> tranformations using just a x-shift and y-shift parameter, and a
> rotation angle having set a point as origin (or just around the
> "center" of the raster).

some ideas.

simple translation without rotation: r.region

90 deg rotation / flipping:
 r.out.mat -> Matlab or GNU Octave.
 ML>> array_rot = orig_array' ;
 % flip array left-right or up-down
 ML>> array_flip = fliplr( flipud( orig_array ) ) ;
 r.in.mat

for rotation by angle you could do more complicated stuff in Matlab.


In GRASS i.rectify may be an option.


Hamish



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