Fill Nodes according to table/data file

Question

I have a lattice of nodes generated by two \foreach commands. So each node has two numbers which define its location (essentially x and y coordinates). Is there any way to fill a circle at that node according to a value in a table.

I wish to do this as the colour I would like is generated by a piece of Matlab script based on a model. So basically the ideal would be to have TikZ look up the current nodes location say (4,5) in a table which would give it the colour it should be.

Is there any way to do this or am I asking too much?

Answer 1

if you can provide the colors as a list like color1 & color2 & color3 & ... you could do it like this:

\documentclass[parskip]{scrartcl}
\usepackage[margin=15mm]{geometry}
\usepackage{tikz}
\usepackage{arrayjobx}
\usepackage{trimspaces}

\makeatletter
\def\trimspace#1{\trim@spaces@in{#1}}
\makeatother

\newarray\temp
\readarray{temp}{yellow&blue&red&red&yellow&blue&red&blue&green&yellow&green&green&yellow&red&blue&yellow&
red&red&blue&green&yellow&yellow&yellow&green&green&red&green&green&green&red&green&red&red&blue&yellow&red&
red&green&yellow&blue&blue&blue&blue&red&red&blue&blue&green&red&red&red&blue&red&blue&red&green&red&red&
green&red&yellow&green&green&yellow&blue&green&red&green&green&green&green&blue&red&yellow&yellow&yellow&
blue&yellow&yellow&green&blue&yellow&blue&yellow&blue&yellow&green&red&blue&yellow&blue&blue&red&yellow&
yellow&green&red&green&green&blue&blue&yellow&green&green&green&red&yellow&blue&red&yellow}
\dataheight=10

\begin{document}

\begin{tikzpicture}
    \foreach \x in {1,...,10}
    {   \foreach \y in {1,...,10}
        {   \pgfmathtruncatemacro{\xt}{\x}
            \pgfmathtruncatemacro{\yt}{\y}
            \checktemp(\xt,\yt)
            \trimspace\cachedata
            \node[inner sep=0.3pt, fill=\cachedata, minimum width=0.9cm, minimum height=0.9cm] at (\xt,\yt) {};
        }
    }
\end{tikzpicture}

\end{document}

---

Edit 1: As suggested by Jake, here's a variant where your color data would be numbered, again separated by &:

\documentclass[parskip]{scrartcl}
\usepackage[margin=15mm]{geometry}
\usepackage{tikz}
\usepackage{arrayjobx}
\usepackage{trimspaces}

\makeatletter
\def\trimspace#1{\trim@spaces@in{#1}}
\makeatother

%\newarray\temp
%\readarray{temp}{yellow&blue&red&red&yellow&blue&red&blue&green&yellow&green&green&yellow&red&blue&yellow&
%red&red&blue&green&yellow&yellow&yellow&green&green&red&green&green&green&red&green&red&red&blue&yellow&red&
%red&green&yellow&blue&blue&blue&blue&red&red&blue&blue&green&red&red&red&blue&red&blue&red&green&red&red&
%green&red&yellow&green&green&yellow&blue&green&red&green&green&green&green&blue&red&yellow&yellow&yellow&
%blue&yellow&yellow&green&blue&yellow&blue&yellow&blue&yellow&green&red&blue&yellow&blue&blue&red&yellow&
%yellow&green&red&green&green&blue&blue&yellow&green&green&green&red&yellow&blue&red&yellow}
%\dataheight=10

\newarray\numbers
\readarray{numbers}{2 & 6 & 2 & 4 & 5 & 6 & 1 & 5 & 6 & 3 & 3 & 2 & 6 & 4 & 5 & 4 & 6 & 4 & 5 & 6 & 5 & 1 & 3 & 6 & 5 & 6 & 4 & 6 & 1 & 6 & 5 & 4 & 4 & 4 & 3 & 2 & 3 & 3 & 2 & 6 & 2 & 4 & 5 & 2 & 4 & 1 & 3 & 5 & 1 & 4 & 1 & 1 & 5 & 4 & 2 & 6 & 2 & 2 & 1 & 2 & 2 & 1 & 5 & 1 & 6 & 4 & 4 & 2 & 1 & 3 & 4 & 3 & 3 & 5 & 1 & 1 & 3 & 2 & 5 & 6 & 2 & 3 & 2 & 4 & 6 & 2 & 1 & 1 & 4 & 6 & 1 & 1 & 1 & 1 & 3 & 4 & 3 & 6 & 5 & 5}
\dataheight=10


\begin{document}

%\begin{tikzpicture}
%   \foreach \x in {1,...,10}
%   {   \foreach \y in {1,...,10}
%       {   \pgfmathtruncatemacro{\xt}{\x}
%           \pgfmathtruncatemacro{\yt}{\y}
%           \checktemp(\xt,\yt)
%           \trimspace\cachedata
%           \node[inner sep=0pt, fill=\cachedata, minimum width=0.9cm, minimum height=0.9cm] at (\xt,\yt) {};
%       }
%   }
%\end{tikzpicture}

\begin{tikzpicture}
[   1/.style={fill=red!50!gray},
    2/.style={fill=yellow!50!gray},
    3/.style={fill=blue!50!gray},
    4/.style={fill=orange!50!gray},
    5/.style={fill=violet!50!gray},
    6/.style={fill=green!50!gray}
]
    \foreach \x in {1,...,10}
    {   \foreach \y in {1,...,10}
        {   \pgfmathtruncatemacro{\xt}{\x}
            \pgfmathtruncatemacro{\yt}{\y}
            \checknumbers(\xt,\yt)
            \trimspace\cachedata
            \node[inner sep=0pt, \cachedata, minimum width=0.95cm, minimum height=0.95cm,rounded corners=0.1cm] at (\xt,\yt) {};
        }
    }
\end{tikzpicture}

\end{document}