[Tex/LaTex] Reverse graphics in pgfplots

MATLABmatlab2tikzpgfplots

Issue and Question

I encountered that my graphics are all upside down. Now I have to mirror them in pgfplots. How can I perform this step?

It is no solution using the option [y dir=reverse] which also turns the axis label upside down (MWE):

\documentclass{standalone}
\usepackage{pgfplots}

\begin{document}
\begin{tikzpicture}
\begin{axis}[y dir=reverse]
    \addplot graphics {GraphicsFile.png};
\end{axis}
\end{tikzpicture}
\end{document}

Appearance

This issue appeared due to the usage of matlab2tikz where in MATLAB. I performed the following command to correct the orientation.

set(gca,'Ydir','normal');

Now that I applied all changes/adaptations to my figures I do not want to go back. But maybe you could also give a short answer about improving my usage of MATLAB.

Best Answer

To flip your graphic, you can pass options to the plot graphics/node to scale the node vertically by -1 and change its default anchor point:

Sample output

\documentclass{article}

\usepackage{pgfplots}
\pgfplotsset{compat=1.9}

\begin{document}

\begin{tikzpicture}
  \begin{axis}
    \addplot[plot graphics/node/.append style={yscale=-1,anchor=north west}] 
      graphics[xmin=0,xmax=2,ymin=0,ymax=2] {example-image-a};
  \end{axis}
\end{tikzpicture}

\end{document}

By default the node has anchor at south west.

Generally one can pass \includegraphics options to the via

\addplot graphics[includegraphics={options}] {image-file};

but no combination of the includegraphics options does a reverse of orientation, so we have to pass the options to the node instead.

Related Solutions

[Tex/LaTex] plotting two time series with bounds

This happens because PGFPlots only uses one "stack" per axis: You're stacking the second confidence interval on top of the first. The easiest way to fix this is probably to use the approach described in "Is there an easy way of using line thickness as error indicator in a plot?": After plotting the first confidence interval, stack the upper bound on top again, using stack dir=minus. That way, the stack will be reset to zero, and you can draw the second confidence interval in the same fashion as the first:

\documentclass{standalone}
\usepackage{pgfplots, tikz}

\usepackage{pgfplotstable}

\pgfplotstableread{
temps   y_h y_h__inf    y_h__sup    y_f y_f__inf    y_f__sup    

1   0.237340    0.135170    0.339511    0.237653    0.135482    0.339823    
2   0.561320    0.422007    0.700633    0.165871    0.026558    0.305184    
3   0.694760    0.534205    0.855314    0.074856    -0.085698   0.235411    
4   0.728306    0.560179    0.896432    0.003361    -0.164765   0.171487    
5   0.711710    0.544944    0.878477    -0.044582   -0.211349   0.122184    
6   0.671241    0.511191    0.831291    -0.073347   -0.233397   0.086703    
7   0.621177    0.471219    0.771135    -0.088418   -0.238376   0.061540    
8   0.569354    0.431826    0.706882    -0.094382   -0.231910   0.043146    
9   0.519973    0.396571    0.643376    -0.094619   -0.218022   0.028783    
10  0.475121    0.366990    0.583251    -0.091467   -0.199598   0.016664    
}{\table}

\begin{document}
\begin{tikzpicture}

    \begin{axis}
    % y_h confidence interval
    \addplot [stack plots=y, fill=none, draw=none, forget plot]   table [x=temps, y=y_h__inf]   {\table} \closedcycle;
    \addplot [stack plots=y, fill=gray!50, opacity=0.4, draw opacity=0, area legend]   table [x=temps, y expr=\thisrow{y_h__sup}-\thisrow{y_h__inf}]   {\table} \closedcycle;
    % subtract the upper bound so our stack is back at zero
    \addplot [stack plots=y, stack dir=minus, forget plot, draw=none] table [x=temps, y=y_h__sup] {\table};

    % y_f confidence interval
    \addplot [stack plots=y, fill=none, draw=none, forget plot]   table [x=temps, y=y_f__inf]   {\table} \closedcycle;
    \addplot [stack plots=y, fill=gray!50, opacity=0.4, draw opacity=0, area legend]   table [x=temps, y expr=\thisrow{y_f__sup}-\thisrow{y_f__inf}]   {\table} \closedcycle;

    % the line plots (y_h and y_f)    
    \addplot [stack plots=false, very thick,smooth,blue]  table [x=temps, y=y_h]   {\table};
    \addplot [stack plots=false, very thick,smooth,blue]  table [x=temps, y=y_f]   {\table};
    \end{axis}

\end{tikzpicture}
\end{document}

[Tex/LaTex] pgfplots surf plot: don’t draw ‘NaN’

I have found a quick n'dirty solution to the problem.

Instead of preventing nan fields from being drawn, I rendered them transparent. To do so, I set opacity of the fields depending on the point meta data. The opacity has to be = 0 for nan fields and >= 1 for other fields.

Therefore, the value of point meta min has to be slightly lower than the smallest point meta value (depending on the numerical resolution), so that ceil(pgfplotspointmetatransformed) >= 1 for the point with the smallest point meta.

The opacity is then set to opacity = ceil(\pgfplotspointmetatransformed). (ceil has to be defined) Since pgfplots sets all nan point meta values to point meta min, they appear transparent. Note that the border is not drawn for nan fields.

Here's the code:

\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{compat=1.10}
\begin{document}

\tikzset{
    declare function={Ceil(\x)=round(\x+0.49999);}
}

\begin{tikzpicture}

    \begin{axis}[%
        view={0}{90},
        scale only axis,
        xmin=1, xmax=5,ymin=1,ymax=5,zmin=-1,zmax=1,
        hide axis,
        colormap/jet,
        colorbar,
        point meta min=0.999999,
        point meta max=100
    ]

    \addplot3[%
        surf,
        shader=flat corner,
        draw=black,
        colormap/jet,
        point meta=explicit,
        opacity=Ceil(\pgfplotspointmetatransformed),
        mesh/rows=5
    ]
    table[row sep=crcr,header=false,meta index=3] {
        1   1   0   1  \\
        1   2   0   10  \\
        1   3   0   20  \\
        1   4   0   30  \\
        1   5   0   1  \\
        2   1   0   40  \\
        2   2   0   nan  \\
        2   3   0   50  \\
        2   4   0   60   \\
        2   5   0   1  \\
        3   1   0   70  \\
        3   2   0   80  \\
        3   3   0   90   \\
        3   4   0   nan  \\
        3   5   0   1  \\
        4   1   0   75  \\
        4   2   0   80  \\
        4   3   0   85  \\
        4   4   0   100  \\
        4   5   0   1  \\
        5   1   0   1  \\
        5   2   0   1  \\
        5   3   0   1   \\
        5   4   0   1   \\
        5   5   0   1   \\
};
\end{axis}
\end{tikzpicture}

\end{document}

And here the output: enter image description here