We study affine invariant 2D triangulation methods. That is, methods that produce the same for a point set S any (unknown) transformation of S. Our work is based on method by Nielson (1993) uses inverse covariance matrix to define an norm, denoted AS, and triangulation, DTAS[S]. revisit AS-norm from geometric perspective, show DTAS[S] can be seen as standard Delaunay transformed prove it retain...