4

Please behold this MWE (compat is at 1.13, so by default the coordinates are in axis cs:): 

\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usepackage{pgfplots}\pgfplotsset{compat=1.13}
\begin{document}

\begin{tikzpicture}[
    ]
     \begin{axis}[
        xmin=0, xmax=1500,   
        ymin=60, ymax=100,
        axis y line* = right,
        axis x line = none,
        clip mode = individual,
    ]
        %\addplot [domain=0:1500] {97-x/150};
        \addplot [domain=0:1500] {x/15};
        \draw [green, <-] (600, 93) -- ++(0,-1.5);
        \draw [red,  <-] (600, 93) -- (600, 93-1.5);
    \end{axis}
\end{tikzpicture}
\end{document}

The two draw commands executes perfectly and they give the same arrow, so you really see just one:

enter image description here

If you now comment out the \addplot and use the previous one, i.e, like this: 

    \addplot [domain=0:1500] {97-x/150};
    %\addplot [domain=0:1500] {x/15};

the relative coordinates \draw goes astray:

enter image description here

Where is my fault? Is that relative movements are not supposed to work in axis cs:? Why it depends on the previous plot?

Rmano
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  • You have to use the axis direction cs for relatve positions: \draw [green, <-] (600, 93) -- ++(axis direction cs:0,-1.5);. – esdd Oct 04 '16 at 13:08
  • By the way, I found it --- it's in chapter 4.17.1 of the documentation. – Rmano Oct 04 '16 at 16:40

1 Answers1

6

axis cs allows only absolute position. If you need relative positions you have to use the axis direction cs:

\draw [green, <-] (600, 93) -- ++(axis direction cs:0,-1.5);

For more information see section "4.17.1 Accessing Axis Coordinates in Graphical Elements" in the documentation of pgfplots.

\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usepackage{pgfplots}\pgfplotsset{compat=1.13}
\begin{document}

\begin{tikzpicture}[
    ]
     \begin{axis}[
        xmin=0, xmax=1500,   
        ymin=60, ymax=100,
        axis y line* = right,
        axis x line = none,
        clip mode = individual,
    ]
        \addplot [domain=0:1500] {97-x/150};
        %\addplot [domain=0:1500] {x/15};
        \draw [green, <-] (600, 93) -- ++(axis direction cs:0,-1.5);
        \draw [red,  <-] (600, 93) -- (600, 93-1.5);
    \end{axis}
\end{tikzpicture}
\end{document}

results in

enter image description here

esdd
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