Re: color in ListContourPlot

• Subject: [mg2250] Re: [mg2230] color in ListContourPlot
• From: ptk at imada.ou.dk (Peder Thusgaard Ruhoff)
• Date: Wed, 18 Oct 1995 05:56:03 GMT
• Approved: usenet@wri.com
• Distribution: local
• Newsgroups: wri.mathgroup
• Organization: Wolfram Research, Inc.
• Sender: daemon at wri.com ( )

```On Tue, 17 Oct 1995, Elizabeth Kraemer <kraemer at service1.uky.edu> wrote:

>
> I want to do a ListContourPlot with a specific color range (from
> white/purple to red).  If I just use "Hue", the high and low values are red.
> I've got a lot of contours, so I want to avoid having to define a color
> individually for each one.  I'm running Mathematica on a Windows machine.
> Thanks for the help!  -Beth
>
>

Dear Beth,

You can use the option ColorFunction.

First let us generate an array of numbers

In[1]:= a = Table[
Sin[x Sin[y Cos[x]]],
{x, -Pi, Pi, Pi/20},
{y, -Pi, Pi, Pi/20}
];

We can get a contour plot in the following way

In[2]:= ListContourPlot[a]

Out[2]= -ContourGraphics-

Now, to change the coloring of the contours we can do the following

In[3]:= ListContourPlot[a, ColorFunction -> (GrayLevel[0.5 + #/2]&)]

Out[3]= -ContourGraphics-

which on my B/W monitor makes the plot much "lighter". I guess you can
do the same in your problem with something like

ColorFunction -> (Hue[#/2]&)

Of course, if you don't like the pure function approach you can define
a function, e.g.

In[4]:= MyOwnColorFunction[val_] := Hue[0.5 + val/2]

In[5]:= ListContourPlot[a, ColorFunction -> MyOwnColorFunction]

Out[5]= -ContourGraphics-

Good luck,

Peder
------------------------------------------------------------------------------
Peder Thusgaard Ruhoff                     Phone: (+45) 66 15 86 96, ext. 2411
Dept. of Mathematics and Computer Science  Fax:   (+45) 65 93 26 91
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