# Setting TikZ curve control points and preserve area of closed curve

I would like to reproduce the shown periodic table, with more correct areas.

http://www.meta-synthesis.com/webbook/35_pt/relative_abundance.jpg

I would appreciate any ideas to how this can be done. How do I in TikZ calculate the area of one box? Can I make the control points auto adjust to a given area, either by iteration, or direct calculation. I do not know the math behind control points!?

Code sample:

\documentclass{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw (0,0) rectangle (3,2);
\draw (0,1) .. controls (0.4,0.4) and (1.5,1.5) ..  (3,1);
\draw (1,0) .. controls (0.4,0.4) and (1.5,1.5) ..  (1,2);
\draw (2,0) .. controls (1.4,1.4) and (1.5,1.5) ..  (2,2);
\end{tikzpicture}
\end{document}


Output:

• Seems as if (1) you have rectangular shapes (2) each consists of 4 bezier curves. You could try the pgfplots library patchplots with patch type=biquadratic or patch type=bicubic... they would require points ON the boundary curves which makes things a little bit simpler. Nov 25 '12 at 13:44
• Jan 17 '13 at 9:07
• @cjorssen: This is really great. I did not know that there was a special name for this kind of mapping - it is helping me a lot. I will look into it, and try to make some TikZ code from it. Mar 22 '13 at 3:19