An affine transformation that preserves area.
Special Affine Transformation
See also
Affine Transformation, Area-Preserving Map, CurvatureExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Special Affine Transformation." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/SpecialAffineTransformation.html