Good morning,

I have some .txt files that contain 3 columns of data: the first one corresponds to the x-axis value of each point, the second one corresponds to the y-axis value of each point, and the third one corresponds to the value that i want in the color bar (meta index).

When I plot the whole thing, the colorbar does not scale with the data in the third column of my txt files.

Here is my code:

```
\documentclass[varwidth]{standalone}
% *** PACKAGES ***
\usepackage{standalone} % Pour les stand-alone
\usepackage[usenames,dvipsnames]{xcolor} % 68 dvips colors à déclarer avant tikz
\usepackage{tikz} % Pour les figure Tikz
\usepackage{pgfplots} % Pour tracer les courbes à partir de fichiers de données
\usepackage{pgfplotstable} % Pour pouvoir lire les tableaux des fichiers .txt
% *** PACKAGES END ***
\pgfplotsset{compat=1.12} % pour définir la version de pgfplots
\pgfplotsset{
/pgfplots/colormap={hsv2}{rgb255(0cm)=(0,0,0) rgb255(0.10cm)=(128,0,128) rgb255(0.5cm)=(0,0,230)
rgb255(1.cm)=(0,255,255) rgb255(2.5cm)=(0,255,0) rgb255(3.5cm)=(255,255,0) rgb255(6cm)=(255,0,0)}
} % Pour définir les couleurs de la colomap
\begin{document}
\tikzset{mark options={mark size=1.5, line width=0.01pt}}
\begin{tikzpicture}
\begin{axis}[
            clip mode=individual, % Pour plot dans l'ordre
            enlargelimits=false,
    colorbar,
    colorbar style={ylabel=$C_{ligne,si}$},%,ytick={0,0.2,...,1}},
    width=0.7\textwidth,
            height=0.6\textwidth,
    grid=major,
    minor x tick num=1,
            xlabel={Real($\lambda (A)$)},
    minor y tick num=1,
            ylabel={Imag($\lambda (A)$)},
    tick label style={font=\footnotesize},
]
\foreach \m in {1,2,...,100}
{\edef\temp{\noexpand\addplot+[mark=*,only marks,scatter,scatter src=explicit] table[x index=0,y index=1,meta index=2] {./DATA_01/Valeurs_Propres_\m.txt};}\temp}
\end{axis}
\end{tikzpicture}
\end{document}

```

and here is the end result that I get:
[![LaTeX output](https://i.stack.imgur.com/qlCnE.png)](https://i.stack.imgur.com/qlCnE.png)

**The color bar starts at 10^-6 and goes up to 10^-3; Now I would like the colorbar to scale logarithmically (instead of linearly) so that the "space" between 10^-6 and 10^-5 is the same than between 10^-5 and 10^-4 and between 10^-4 and 10^-3.**

I am joining a .zip with my folder containing my .tex files and the .txt files if someone is willing to go this far to help me. [You can download it here.](https://filex.supelec.fr/get?k=j4pjYlTW0sEStB488Hl)

Thank you very much for your help!

VS