A geometric transformation that scales, rotates, skews, and/or translates images or coordinates between any two Euclidean spaces. It is commonly used in GIS to transform maps between coordinate systems. In an affine transformation, parallel lines remain parallel, the midpoint of a line segment remains a midpoint, and all points on a straight line remain on a straight line.
In imagery, a six-parameter coordinate transformation that defines the relationship between pixels and an image coordinate system for interior orientation or other geometric transformations. Transformation can include translation, rotation, scale-change, and shearing.