The Delaunay triangulation of a spatial point pattern X
is defined as follows. First the Dirichlet/Voronoi tessellation of X
computed; see dirichlet. Then two points of X
are defined to be Delaunay neighbours if their Dirichlet/Voronoi tiles
share a common boundary. Every pair of Delaunay neighbours is
joined by a straight line.
The graph distance
in the Delaunay triangulation between two points X[i] and X[j]
is the minimum number of edges of the Delaunay triangulation
that must be traversed to go from X[i] to X[j].
This command returns a matrix D such that
D[i,j] is the graph distance
between X[i] and X[j].