# [R] triangular color plot of array

David Carlson dcarlson at tamu.edu
Mon Jul 29 22:22:25 CEST 2013

```A triangular plot can represent three dimensions in a two
dimensional plane because the three dimensions are constrained
by the fact that they sum to 100% (e.g. sand/silt/clay
composition of a soil). That does not seem to apply to your
example. It sounds like you might need a 3d contour plot. You
might look at package misc3d, function countour3d. See the R
Graphical Manual for some examples:

http://rgm3.lab.nig.ac.jp/RGM/R_image_list?package=misc3d

Alternatively you can use lattice to draw 2d contours for a
series of slices. That may not be as snazzy, but it will
probably be easier to interpret.

-------------------------------------
David L Carlson
Associate Professor of Anthropology
Texas A&M University
College Station, TX 77840-4352

-----Original Message-----
From: r-help-bounces at r-project.org
[mailto:r-help-bounces at r-project.org] On Behalf Of White,
William Patrick
Sent: Monday, July 29, 2013 1:54 PM
To: r-help at R-project.org
Subject: [R] triangular color plot of array

Hello,
I've encountered an interesting situation and can't seem to
find an applicable solution. I've got a multivariate synthetic
dataset I generated in order to explore various statistical
techniques. In my dataset I vary three things, sample size,
effect size, and the number of variables that are affected. As
these are varied I've output my results into a three
dimensional array. So for each possible combination, think xyz
location, I have an output value. What I would like to do is
to create a somewhat unique style of plot very similar to a
triangular soil texture plot, excepting that at rather than
dropping a point at a given coordinate, I have all possible
coordinates on the grid, and I would like to overlay a color
map in which combinations that yield high values shade towards
one color, and low values another or some other such color
scheme. Thus displaying under what conditions certain
accuracies are achieved for the test.
I've explored both the soil texture plotting solutions in R,
and as best I can with little background in image work the 3d
plotting solutions offered by various packages. I haven't
found anything that seems to be able to handle an array this
way. I was wondering if anyone could point me in the right
direction.
P~

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