       Re: Does ColorFunction-> have different meanings to Plot3D and

• To: mathgroup at smc.vnet.net
• Subject: [mg83291] Re: [mg83276] Does ColorFunction-> have different meanings to Plot3D and
• From: "Ricardo Samad" <resamad at gmail.com>
• Date: Sat, 17 Nov 2007 05:12:46 -0500 (EST)
• References: <200711161041.FAA05001@smc.vnet.net>

```Dear Roger,

The simplest way is to use Hue instead of (Hue[#]&):

Plot3D[Sin[x + y^2], {x, -3, 3}, {y, -2, 2}, ColorFunction -> Hue]

ContourPlot[Sin[x + y^2], {x, -3, 3}, {y, -2, 2},
ColorFunction -> Hue]

When you define the CF as you did, in ContourPlot the CF is related to the =
z
coordinate, or the function height, as expected, but in Plot3D there are
three arguments for the CF: # or #1 is the x-coordinate, #2 the y-coordinat=
e
and #3 the z-coordinate, the one that you want:

Plot3D[Sin[x + y^2], {x, -3, 3}, {y, -2, 2},
ColorFunction -> (Hue[#3] &)]

ContourPlot[Sin[x + y^2], {x, -3, 3}, {y, -2, 2},
ColorFunction -> Hue]

This second syntax offers more control over the plot, as for example in:

Plot3D[Sin[x + y^2], {x, -3, 3}, {y, -2, 2},
ColorFunction -> (Hue[#1 + #2 + #3] &), PlotPoints -> 50,
Mesh -> False]

Best regards,

Ricardo

On Nov 16, 2007 7:41 AM, <congruentialuminaire at yahoo.com> wrote:

> Hello Mathematica UG:
>
> I made a very simple 3D plot using a CF:
>
> Plot3D[Sin[x + y^2], {x, -3, 3}, {y, -2, 2},  ColorFunction -> (Hue[#]
> &)]
>
> Then I made a contour plot of the identical function, also with CF:
>
> ContourPLot[Sin[x + y^2], {x, -3, 3}, {y, -2, 2},  ColorFunction ->
> (Hue[#] &)]
>
> Since I am using the identical function passed to the 2 plotting
> routines, I expect the color to show analogously. Specifically in the
> Plot3D, the color bands are straight and parallel to the y-axis. In
> the ContourPlot, the bands are curved with the contours.
>
> Is it possible to make the CF correspond so that when both plots are
> shown, the color shows the correspondence between the plots (since the
> functions plotted are the same)? Alternatively, is there some other CF
> I can use with ContourPlot to accomplish the desired result?
>
> TIA.
>
> Regards..Roger W.
>
>

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