ListContourPlot Color

[Moranr...@aol.com]

Is the a way to assign specific colors to the intervals between individual
contours?
Thank you. John R Moran PhD,MD

[Jens-Peer Kuska]

Hi,

data = Table[N[Exp[-x^2 - y^2]*x], {y, -2, 2, 0.05}, {x, -2, 2, 0.05}];

{zmin, zmax} = {Min[#], Max[#]} & [Flatten[data]];
colorf[sz_] := Module[{z}, z = (zmax - zmin)*sz + zmin;
Which[
z < -0.3, RGBColor[1, 0,
0],
z < -0.15, RGBColor[1, 1,
0],
z < 0, RGBColor[0, 1, 0],
z < 0.15, RGBColor[0, 1,
1],
z < 0.3, RGBColor[0, 0, 1],
True, RGBColor[1, 0, 1]
]]

ListContourPlot[data, Contours -> {-0.3, -0.15, 0.15, 0.3},
ColorFunction -> colorf]

works fine.

Regards
Jens

[BobH...@aol.com]

In a message dated 2001/11/7 5:46:57 AM, Moranr...@aol.com writes:

>Is the a way to assign specific colors to the intervals between individual
>
>contours?
>

ListContourPlot[
Table[x^2+y^2+Random[Real,{-0.2,0.2}],
{x,-2,2,0.1},{y,-2,2,0.1}],
ContourStyle->RGBColor[0,0,1]];

ListContourPlot[
Table[x^2+y^2+Random[Real,{-0.2,0.2}],
{x,-2,2,0.1},{y,-2,2,0.1}],
ContourStyle->{{RGBColor[0,0,1]},{RGBColor[1,0,0]}}];

ListContourPlot[
Table[x^2+y^2+Random[Real,{-0.2,0.2}],{x,-2,2,0.1},{y,-2,2,0.1}],
ContourStyle->Join[
Table[{RGBColor[0,0,1]},{2}],
{RGBColor[1,0,0]}]];

Bob Hanlon
Chantilly, VA USA

[Anton Antonov]

Hi there,
You can try this modifyed exmaple from the help:

ListContourPlot[
Table[x^2 + y^2 + Random[Real, {-0.2, 0.2}],
{x, -2, 2, 0.1}, {y, -2, 2, 0.1}],
ColorFunction -> (Hue[1 - #1] &)];

I added a rule for the option 'ColorFunction'. For the options
avalable in 'ListContourPlot' you should refer to 'ContourGraphics'.

Best,
Anton

==============================================================
Anton Antonov Antonov, PhD ***** Wolfram Research Inc.
http://www.imm.dtu.dk/~uniaaa *** tel +1 217 398 0700 #782
==============================================================
Give me wings and I will crawl faster!
--------------------------------------------------------------

On Wed, 7 Nov 2001 Moranr...@aol.com wrote:

> Is the a way to assign specific colors to the intervals between individual
> contours?

[Moranr...@aol.com]

Bob, Thank you. Those are very nice but what I had in mind was to assign
colors to the area between your red and blue lines which are currently
GreyLevel in your plot. Thank you. John

[David Park]

John,

Yes, you can explicitly color each contour range. Here is an example. I used
a ContourPlot instead of a ListContourPlot to save the extra steps of
generating a set of data.

Needs["Graphics`Colors`"]

colfun[contourvals_, colorlist_][z_] := Module[{i},
If[z > Last[contourvals], Return[Last[colorlist]]];
i = 1;
While[z > contourvals[[i]], i++];
colorlist[[i]]]

contourvals = Range[0.2, 0.8, 0.1];
colorlist = {Gray, RoyalBlue, AureolineYellow, RoyalBlue, AureolineYellow,
RoyalBlue, AureolineYellow, Gray};

ContourPlot[Sin[x]Sin[y], {x, 0, Pi}, {y, 0, Pi},
Contours -> contourvals,
ColorFunction -> colfun[contourvals, colorlist],
ColorFunctionScaling -> False,
PlotPoints -> 25,
ImageSize -> 400];

I will comment on several techniques I used in this plot.
1) I needed to give the contour values explicitly since the color function
uses them.
2) I used ColorFunctionScaling -> False so that the z values that
Mathematica feeds to the color function are the actual values. Otherwise
Mathematica scales the z values from 0 to 1, which will not generally be
what you want.
3) I picked out only a subrange of contours to plot. Low and high values
were colored Gray. The color list should contain one more entry than the
contour values list. The first and last items are the under and over value
colors.

David Park
dj...@earthlink.net
http://home.earthlink.net/~djmp/

[Allan Hayes]

<Moranr...@aol.com> wrote in message news:9sb4pf$gg4$1...@smc.vnet.net...

> Is the a way to assign specific colors to the intervals between individual
> contours?
> Thank you. John R Moran PhD,MD
>

John,

Here is a way:

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--
Allan
---------------------
Allan Hayes
Mathematica Training and Consulting
Leicester UK
www.haystack.demon.co.uk
h...@haystack.demon.co.uk
Voice: +44 (0)116 271 4198
Fax: +44 (0)870 164 0565

[BobH...@aol.com]

ListContourPlot[
Table[x^2+y^2+Random[Real,{-0.2,0.2}],
{x,-2,2,0.1},{y,-2,2,0.1}],

ColorFunction -> Hue];

Needs["Graphics`Colors`"];

cf[x_] := Which[
x >.5, Red,
x > .3, Orange,
x > .1, Yellow,
x > 0.05, Green,
True, Blue
];

ListContourPlot[
Table[x^2+y^2+Random[Real,{-0.2,0.2}],
{x,-2,2,0.1},{y,-2,2,0.1}],

ColorFunction -> cf];

In a message dated 2001/11/7 6:43:12 AM, writes:

>
>In a message dated 2001/11/7 5:46:57 AM, Moranr...@aol.com writes:
>

>>Is the a way to assign specific colors to the intervals between individual
>>
>>contours?
>>
>