       Re: Special 3D Plots

• To: mathgroup at smc.vnet.net
• Subject: [mg19792] Re: Special 3D Plots
• From: "Allan Hayes" <hay at haystack.demon.co.uk>
• Date: Fri, 17 Sep 1999 01:36:46 -0400
• References: <7rnkjg\$em9@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Lindsay Magnus <l.magnus at ru.ac.za> wrote in message
news:7rnkjg\$em9 at smc.vnet.net...
> I need some advice to try and create a special plot.  I want to give
> mathematica a data file that contains 3D data.  In this I mean that
> every datum point has three values associated with it. (x,y and z for
> example). I want to plot a graph where the x-axis is given by the x
> value, the y-axis is given by the y value and the color of the block at
> co-ordinates (x,y) is given by the z value.
>
> thanx for the time
> lins
>
>

Lins,

The crucial point is to convert each triple {x,y,z} into
{cf[z],Point[{x,y}]}, where cf is a function (color function) thart takes z
and returns a color directive.

coloredPoints[data_, cf_] :=
Show[Graphics[{PointSize[.02],
Apply[{cf[#3], Point[{#1, #2}]} &, data, {1}]}]]

In Mathematica 4.0 we can abreviate this to

coloredPoints[data_, cf_] :=
Show[Graphics[{PointSize[.02], {cf[#3], Point[{#1, #2}]} & @@@ data}]]

Try

data = Table[Random[], {50}, {3}];

coloredPoints[data, Hue[.67#] &];

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

```

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