  This paper introduces invariant transforms that preserve the ratio of either
two or three co-linear points in the Desargues affine plane skew field. The
results given here have a clean, geometric presentation based based Desargues
affine plan axiomatic and definitions with skew field properties. The main
results in this paper, are (1) ratio of two and three points is
\emph{Invariant} under transforms: Inversion, Natural Translation, Natural
dilatation, Mobi\"us Transform, in a line of Desargues affine plane. (2)
parallel projection of a pair of lines in the Desargues affine plane preserves
the ratio of two and three points, (3) translations in the Desargues affine
plane preserve the ratio of 2 and 3 points and (4) dilatation in the Desargues
affine plane preserve the ratio of 2 and 3 points.
