Similarity

Overview

A shape refers to the geometric information that remains when position, size, orientation, and chirality are removed from the description of a geometric object.

Similarity

Two sets of points are similar if one can be obtained from the other by uniformly scaling, possibly with additional translation, rotation, and reflection.

Congruence

Two sets of points are congruent if and only if one can be obtained from the other by just translation, rotation, and reflection.

Said in another way, the sets are congruent if their points can be put in one-to-one correspondence in such a way that distances are preserved.