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copied!<p>R has an external package called <a href="http://www.math.yorku.ca/SCS/vcd/" rel="nofollow noreferrer">VCD</a> which should do what you want. </p> <p>The documentation is very good (122 page manual distributed w/ the package); there's also a book by the same name, <em>Visual Display of Quantitative Information</em>, by the package's author (Prof. Michael Friendly).</p> <p>To create ternary plots using <strong>vcd</strong>, just call <strong><em>ternaryplot()</em></strong> and pass in an m x 3 matrix, i.e., a matrix with three columns. </p> <p>The method signature is very simple; only a single parameter (the m x 3 data matrix) is required; and all of the keyword parameters relate to the plot's aesthetics, except for scale, which when set to 1, normalizes the data column-wise.</p> <p>To plot data points on the ternary plot, the coordinates for a given point are calculated as the <em>gravity center of mass points</em> in which each feature value comprising the data matrix is a separate <em>weight</em>, hence the coordinates of a point V(a, b, c) are</p> <pre><code>V(b, c/2, c * (3^.5)/2 </code></pre> <p>To generate the diagram below, i just created some fake data to represent four different chemical mixtures, each comprised of varying fractions of three substances (x, y, z). I scaled the input (so x + y + z = 1) but the function will do it for you if you pass in a value for its 'scale' parameter (in fact, the default is 1, which i believe is what your question requires). I used different colors & symbols to represent the four data points, but you can also just use a single color/symbol and label each point (via the 'id' argument). </p> <p><a href="http://www.freeimagehosting.net/uploads/35393eaba5.png" rel="nofollow noreferrer">http://www.freeimagehosting.net/uploads/35393eaba5.png</a></p>

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