Introduction - If you have any usage issues, please Google them yourself
TRICONTOUR Triangular Contour Plot.
TRICONTOUR(TRI,X,Y,Z,N) draws scalar N contour lines treating the values
in Z as heights above a plane. TRI,X,Y,and Z define a triangulation where
the triangles are defined by the M-by-3 face matrix TRI, such as that
returned by DELAUNAY. Each row of TRI contains indices into the X,Y, and
Z vertex vectors to define a single triangular face. Contours are
computed directly from the triangulation rather than interpolating back
to a cartesian grid using GRIDDATA.
TRICONTOUR(TRI,X,Y,Z,V) draws length(V) contour lines at the values
specified in vector V.
TRICONTOUR(TRI,X,Y,Z,[v v]) draws a single contour line at the level v.