Re: ListPlot + Colors
- To: mathgroup@smc.vnet.net
- Subject: [mg12206] Re: ListPlot + Colors
- From: "John M. Jowett" <John.Jowett@cern.ch>
- Date: Fri, 1 May 1998 03:08:55 -0400
- Organization: CERN
- References: <199804240552.BAA13327@smc.vnet.net.> <6i0sqe$8lf@smc.vnet.net> <35446191.A582035@cern.ch> <35453757.506D@worldnet.att.net>
(In an exchange of email), Sean Ross wrote:
> Thanks for the information, but I regard the ColorListPlot as inadequate
> as well. I want full control of color as a function of x,y and z
> coordinates specified in a ColorFunction type construct. At present,
> the 3-D graphs in mathematica only give that kind of control as a
> function of z. The 2-D don't give any such options. ColorListPlot
> progresses through the Hues as a function of the path length of the
> curve. This is a wonderful step in the right direction, but still does
> not give me full color control. As soon as I can figure out how to
> write packages and manipulate options, I plan to write such a function.
Sean,
You can colour the points in various ways by giving an appropriate
ColorScale function as an option. It is not difficult to make the
colour depend on a third z value. Using the sample data in
ColorListPlot.nb, try
zvalues = (Sqrt[Mod[#[[1]]^2+#[[2]]^2,1]])& /@ data
to get a list of hue values periodic in the radial coordinate of each
point. Then you can use
ihue[z_]:=Hue[zvalues[[Floor[1+z( Length[data]-1)+.3]]]]
as a colouring function in
colorListPlot[data,ColorScale->ihue]
This is just an example. zvalues could be any list of the same length
as data, e.g., the z coordinate of a list of {x,y,z} values.
In fact you inspired me to make a simple extension of colorListPlot in
the package. Now, if you download the new version of the
ColorListPlot package from
http://wwwslap.cern.ch/~jowett/Madtomma/
construct a list of {x,y,z} values like
data3=Table[{t Cos[t],t Sin[2t],t Sin[3t]},{t,0,7Pi,Pi/16}];
and simply do
colorListPlot[data3]
you'll get a plot where the colour of each point indicates the z value
instead of its order in the list. This is now in the Examples section
of the notebook. However using the ColorScale option with 2D data still
provides more possibilities.
John Jowett
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