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SUBROUTINE DEM80 (NIN,NOUT)
C$ (DEM80 - Triangulated Surface Contour Plot)
C$ Demonstration of contour plotting directly from a
C$ triangulation of irregularly-distributed data points
C$ without the generation of an intermediate uniform grid of
C$ points, as implemented by routine CONTCP. Subwindowing is
C$ used to display detail and illustrate that the contouring
C$ remains smooth under magnification.
C$
C$ The function triangulation is already available for the
C$ figure, which is a box wrench on which stress contours are
C$ to be plotted. Since triangulation algorithms produce a
C$ set of triangles covering the convex hull (i.e. smallest
C$ enclosing convex polygon) of the data points, the output of
C$ such a triangulation was hand edited to remove triangles
C$ outside the body of the wrench.
C$
C$ In the first plot, derivatives are estimated automatically,
C$ and in the second, they are explicitly specified. An
C$ important feature of CONTCP is that it automatically
C$ restricts the contouring to the triangulated area,
C$ permitting contouring of irregular regions.
C$
C$ The fitting method is a slightly modified version of H.
C$ Akima's ACM Algorithm 526 (routines FITVCM, FITVPD, FITVTA,
C$ and FITVXC), and corresponds to demonstration program
C$ TPDEM2 in Preusser's ACM Algorithm 626.
C$ (13-SEP-85)