contour labelling [was "Re: [R] image ()"]

Bill Simpson wsimpson at
Fri Dec 4 19:46:31 CET 1998

> There is Delaunay code in the R package tripack, and, implicitly, in
> package akima which may well be helpful: if I understand Bill
> correctly he wants to put a plane on each triangle to get a surface (which
> is interpolation) and Akima was more sophisticated and used quintics
> to achieve a smooth interpolated surface. We may be missing the crux
> here: was it to have a means of displaying such surfaces?
Yes, bang on. I knew of the existence of the Delaunay code in the R
libraries. Yes I want to make a picture that places a planar facet on each
triangle. The resulting surface looks like the surface of a cut diamond
for example (assuming the cuts give triangular facets). So far as I know
there is no way to display such a 3D plot in R. persp uses rectangular
rather than triangular mesh.

>From the description of the akima package, it sounded like it just did
some of the work required PRIOR to making the 3D plot. But that is useless
if I can't make the plot.

I think of it as the 3D version of the 2D  
connect-the-dots-with-line-segments plot. Now the points are connected by
planes rather than lines.


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