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RE: coloured contour plots

  • To: mathgroup at
  • Subject: [mg32955] RE: [mg32936] coloured contour plots
  • From: "David Park" <djmp at>
  • Date: Thu, 21 Feb 2002 02:07:11 -0500 (EST)
  • Sender: owner-wri-mathgroup at


My package DrawGraphics, available at my web site below, contains routines
for making nonrectangular colored contour plots. The example under
FineGrainPolygons in the DrawGrahics Help shows a case of a colored circular
contour plot.

The procedure is as follows:
1) The routine ContourDraw works just like ContourPlot but extracts the
primitive graphics without display of the plot.
2) Suppose you want to make a contour plot in which coordinate lines in an
rs-coordinate system will be displayed in the xy-coordinate system with
constant r or constant s lines as the boundaries. (Circular plots are made
by using an r-theta coordinate system with the boundary r = constant.) Make
a rectangular contour plot using ContourDraw in the rs-coordinates.
3) Use a routine called FineGrainPolygons to change any long straight line
segments, bounded by two points, in the polygons to multiple points. These
usually occur at the boundaries of the rs plot. This is necessary for the
smooth operation of the next step.
4) Use a routine called DrawingTransform to transform, or map, the graphics
from the rs plane to the xy plane. Then you will obtain a nice
nonrectangular colored contour plot bounded by r and s coordinate lines.

David Park
djmp at

> From: Devendra.Natekar at
To: mathgroup at
> Hi
> I am trying to generate coloured contour plots from a certain set
> of data I have
> However one of my requirements is that the underlying shape of
> the plot should
> be that of the geometry which I have.
> In other words I want a coloured contour plot on an arbitrary
> underlying shape
> and not a quadrilateral.
> Currently I am using:
> Show[Graphics[({Hue[hued11[[#1 + 1, 1]]*2], PointSize[0.02],
>             Point[finpos[[#1 + 1]]]} &) /@ Range[0, rmgpt - 1, 1],
>     AspectRatio -> Automatic]]
> This plots the data points at the co-ordinates given in the array
> "finpos" and
> gives them a colour specified by the array "hued11". However the
> plot is not
> continous and made up of a series of points.
> Is it possible to generate a continous plot having arbitrary
> shape and not a
> square or a cube contour plot?
> Thanks
> Deven
> The philosopher has never killed any priests,
> whereas the priest has killed a great many philosophers.

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