# PGFplots Math Error

On one of my PGF plots I receive the following errors which I can't really relate. What I am doing is to overlay 3-D data with x-y and z-values for different measurements (the plotting of each layer is done as described in Plotting matrix image data :

Package PGF Math Error: Could not parse input 'pgfpmth@fl' as a floating point number, sorry. The unreadable part was near 'pgfpmth@fl'.. \end{tikzpicture}

Package pgfplots Error: the arguments of [mesh/rows=194,mesh/cols=194] assumebe incomplete or overcomplete!? [Use mesh/check=false to disable this message]. \end{tikzpicture}

My file looks as follows:

\tikzsetnextfilename{filenamexyz}
\begin{tikzpicture}
\begin{axis}
[view={0}{90},
xlabel=$x / \si{pixel}$,
ylabel=$y / \si{pixel}$,
width=0.75\textwidth,
ticklabel style = {font=\footnotesize}
]

\node[anchor=east, font=\footnotesize] (source) at (axis cs:150,170){Position 1};
\node (destination) at (axis cs:190,170){};
\draw[->](source)--(destination);

\node[anchor=east, font=\footnotesize] (source) at (axis cs:150,23){Position 2};
\node (destination) at (axis cs:190,23){};
\draw[->](source)--(destination);

\node[anchor=west, font=\footnotesize] (source) at (axis cs:25,20){Position 4};
\node (destination) at (axis cs:1,1){};
\draw[->](source)--(destination);

\node[anchor=east, font=\footnotesize] (source) at (axis cs:40,97){Position 3};
\node (destination) at (axis cs:80,97){};
\draw[->](source)--(destination);

\end{axis}
\end{tikzpicture}


with the file1...txt files containing three columns with the coordinates in column 0 and 1 and the values plotted in colors in the third column. Like this:

1 1 20
2 1 21
1 2 25
2 2 19


The compilation worked without errors a year ago, but does not anymore. I'm using pdflatex and bibtex8 as compilers. The picture is for some reason shown correctly but the errors are somewhat against my ambitions.

• Please post a complete MWE. – JPi Jul 31 '17 at 20:35
• Are you using matrices or externalisation? If not, why have you added those tags? If so, what is their relevance to the question? – cfr Jul 31 '17 at 23:18
• The data used for the plot are in a three dimensional matrix, the picture is externalized, I guess that either one could have an influence on the errors, that's why – nmy2015 Aug 1 '17 at 19:29