27.4. Affine 2D |
Also known as 6-parameter transformation. It is the general case of the 4-parameter Helmert transformation, where different scales are used for the X and Y axes and where, moreover, these axes are not orthogonal. At least three pairs of points are necessary.
Formulas:
where:
x', y' = Transformed X, Y coordinates
x,y = Original X,Y coordinates
Sx = Scale X
Sy = Scale Y
= Rotation angle
= Orthogonality correction angleTx = Translation X
Ty = Translation Y
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