Problems using TWJ contour for irregular data

• To: mathgroup at smc.vnet.net
• Subject: [mg13204] Problems using TWJ contour for irregular data
• From: Joel Cannon <cannon at alpha.centenary.edu>
• Date: Mon, 13 Jul 1998 07:42:53 -0400
• Sender: owner-wri-mathgroup at wolfram.com

```Does anyone have experience using Tom Wickham-Jones contour function for
generating contour plots from irregularly spaced data (using M3.0)? I
and put the suffix .exe on the binary file compiled with mcc. However,
I am unable to duplicate the example found on page 483 of the book.

I will attempt to past the results out of the notebook below. When
calling either TrianglePlot or ListContourPlot, I get an error message
printed to the shell that launched mathematica saying,  "Assertion
failed: FALSE, file delaunay.tm.c, line 198".

In[1]:=
Needs["ExtendGraphics`Contour`"]

In[2]:=

Out[2]=

(*   Generate an irregularly spaced array of x,y,z points *)

d1 = Flatten[
Table[
Table[{r,Sin[t],r^2 Cos[t] Sin[t]},
{t,0,2Pi-2Pi/(10r),2Pi/(10 r)}],
{r,10}],1];

In[4]:=
Dimensions[d1]

Out[4]=
{550,3}

(*  Attempt a TrianglePlot with the data *)

In[5]:=
TrianglePlot[Map[Take[#,2]&,d1]]

Set::"shape": "Lists \!\({ExtendGraphics`Delaunay`Private`hull,
\(\\[LeftSkeleton] 35 \\[RightSkeleton]\)}\) and \!\(\$Failed\) are not
the same shape."

Graphics::"gprim": "Unknown \!\(Graphics\) primitive
\!\(ExtendGraphics`Delaunay`Private`tri\) encountered."

Out[5]=
\[SkeletonIndicator]Graphics\[SkeletonIndicator]

(*  Attempt to use ListContourPlot *)

In[3]:=
c = ListContourPlot[d1]

------------------------------------------------------------------------------
Joel W. Cannon |   (318)869-5160
Dept. of Physics   |   (318)869-5026  FAX    Centenary College of
Louisiana |
P. O. Box 41188		   |
Shreveport, LA 71134-1188  |

```

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