coloured fitting pgfplots

Question

I want to fit this data with a straight line and both the straight line that the points have to follow the color of the colorbar horizontal. Another problem is that I can not adapt the grid scale..

   \documentclass[a4paper,12pt]{article}
\usepackage{pgfplots}
\usepackage{pgfplotstable}

\begin{document}
\begin{figure}
\centering
\pgfplotsset{width=10cm}
\begin{tikzpicture}
\makeatletter \newcommand{\pgfplotsdrawaxis}{\pgfplots@draw@axis} \makeatother
\pgfplotsset{axis line on top/.style={
 axis on top=false,
 after end axis/.append code={
    \pgfplotsset{axis line style=opaque,
      ticklabel style=opaque,
      tick style=opaque,
      grid=none}
    \pgfplotsdrawaxis}
  }
}
\pgfdeclarehorizontalshading{stefan}{50bp}{
color(0.00000000000000bp)=(violet);
color(8.33333333333333bp)=(blue);
color(16.66666666666670bp)=(cyan);
color(25.00000000000000bp)=(green);
color(33.33333333333330bp)=(yellow);
color(41.66666666666670bp)=(orange);
color(50.00000000000000bp)=(red)
}
\begin{axis}[legend pos=outer north east,
grid=major,
xmin=0, xmax=0.2,
ymin=0, ymax=0.4,
point meta min={0},
point meta max={0.2},
axis line on top,
xticklabel style={text height=1.5ex},
xticklabels={%
$0$,
$0.05$,
$0.1$,
$0.15$,
$0.2$,
$0.25$,
$0.3$
},
extra x ticks={0,0.05,...,0.3},
extra x tick labels={%
$0$,
$0.05$,
$0.1$,
$0.15$,
$0.2$,
$0.25$,
$0.3$
},
extra x tick style={
    xticklabel pos=right,
    xticklabel style={text depth=0pt}
},
extra y ticks={0,0.2,...,1},
extra y tick style={
    yticklabel pos=right
},
tick style={thin,black},
minor tick num=3,
xlabel=\large $\mbox{s}$,
ylabel=\large $f_{\mu,\sigma^2}(\mbox{s})$,
colorbar horizontal,
colorbar style={
    xticklabels={%
        $-0.4$,
        $-0.3$,
        $-0.2$,
        $-0.1$,
        $\mu$,
        $0.1$,
        $0.2$,
        $0.3$,
        $0.4$
    },
    xticklabel style={text height=1.5ex}
},
colormap={new}{color(0cm)=(violet);color(1cm)=(blue);color(2cm)=(cyan);color(3cm)=(green);color(4cm)=(yellow);color(5cm)=(orange);color(6cm)=(red)},
after end axis/.append code={
    \draw ({rel axis cs:0,0}-|{axis cs:0,0}) -- ({rel axis cs:0,1}-|{axis cs:0,0});
},
legend cell align=left]
\addplot [
    mark=*,
    draw=none]
    table[row sep=\\] {% plot X versus Y. This is original data.
X Y\\
0.05 0.17\\
0.05 0.041\\
0.05 0.023\\
0.1 0.332\\
0.1 0.089\\
0.1 0.041\\
0.15 0.05\\
0.15 0.132\\
0.15 0.06\\
};
\addplot [no marks] table[row sep=\\,
y={create col/linear regression={y=Y}}] % compute a linear regression from the input table
{
X Y\\
0.05 0.17\\
0.05 0.041\\
0.05 0.023\\
0.1 0.332\\
0.1 0.089\\
0.1 0.041\\
0.15 0.05\\
0.15 0.132\\
0.15 0.06\\
};
%\xdef\slope{\pgfplotstableregressiona} %<-- might be handy occasionally
\end{axis}
\end{tikzpicture}
\end{figure}
\end{document}

I would like a color of the line like this

i possible have this legend?

Answer 1

You'll have to set point meta=explicit and meta=X. To get a smoother colour transition and to be able to set define over what domain the regression line is drawn, you'll have to calculate the parameters of the regression line first using

\pgfplotstablecreatecol[linear regression]
{regression}
{\datatable}

\xdef\slope{\pgfplotstableregressiona}
\xdef\intercept{\pgfplotstableregressionb}

and then drawing the line using \addplot [mesh,point meta=x,domain=0:0.2] {\slope*x+\intercept};.

\documentclass[a4paper,12pt]{article}
\usepackage{pgfplots}
\usepackage{pgfplotstable}

\pgfplotstableread{
X Y
0.05 0.17
0.05 0.041
0.05 0.023
0.1 0.332
0.1 0.089
0.1 0.041
0.15 0.5
0.15 0.132
0.15 0.06
}\datatable

\pgfplotstablecreatecol[linear regression]
{regression}
{\datatable}

\xdef\slope{\pgfplotstableregressiona} %<-- might be handy occasionally
\xdef\intercept{\pgfplotstableregressionb}


\begin{document}
\begin{figure}
\centering
\pgfplotsset{width=10cm}
\begin{tikzpicture}
\makeatletter \newcommand{\pgfplotsdrawaxis}{\pgfplots@draw@axis} \makeatother
\pgfplotsset{axis line on top/.style={
 axis on top=false,
 after end axis/.append code={
    \pgfplotsset{axis line style=opaque,
      ticklabel style=opaque,
      tick style=opaque,
      grid=none}
    \pgfplotsdrawaxis}
  }
}
\begin{axis}[/pgf/number format/fixed,
legend pos=outer north east,
grid=major,
xmin=0, xmax=0.2,
ymin=0, ymax=0.6,
point meta min={0},
point meta max={0.2},
minor tick num=4,
axis line on top,
xticklabel style={text height=1.5ex},
xtick={0,0.05,...,0.3},
minor xtick={0,0.01,...,0.2},
extra x ticks={0,0.05,...,0.3},
extra x tick style={
    xticklabel pos=right,
    xticklabel style={text depth=0pt}
},
extra y ticks={0,0.1,...,0.7},
extra y tick style={
    yticklabel pos=right
},
tick style={thin,black},
xlabel=\large $\mbox{m}$,
ylabel=\large $\Delta\mbox{l}$,
colorbar horizontal,
colorbar style={
    /pgf/number format/fixed,
    xtick={0,0.05,...,0.3},
    xticklabel style={text height=1.5ex}
},
colormap={new}{color(0cm)=(violet);color(1cm)=(blue);color(2cm)=(cyan);color(3cm)=(green);color(4cm)=(yellow);color(5cm)=(orange);color(6cm)=(red)},
after end axis/.append code={
    \draw ({rel axis cs:0,0}-|{axis cs:0,0}) -- ({rel axis cs:0,1}-|{axis cs:0,0});
},
legend cell align=left]
\addplot [point meta=explicit,
    scatter,
    mark=*,
    draw=none]
    table[meta=X] {\datatable};

\addplot [mesh,point meta=x,domain=0:0.2] {\slope*x+\intercept};
\end{axis}
\end{tikzpicture}
\end{figure}
\end{document}