# pgfplots chart labels too close and not spaced evenly

i have a set of numbers as x-coordinates:{2.08, 2.09, 2.7, 4.9, 12.8, 29.3, 64.2}. the left part of the diagram is too tight because 2.08 and 2.09 are very close. i want to evenly distribute the set of numbers on x-axis. is it possible? and how? see an example as follows:

\begin{figure}[!h]
\centering
\caption{The example.}
\label{figure:the_example}
\begin{tikzpicture}[scale=0.45]
\begin{axis}[ybar,xtick=data,xlabel=$\lambda$,ylabel=$\alpha$,
x tick label style={rotate=-35,anchor=west},width=2.2\textwidth,
height=0.32\textheight,legend pos=north west,ymin=0]
(2.08,10)
(2.09,15)
(2.7,25)
(4.9,22)
(12.8,21)
(29.3,12)
(64.2,17)
};
\end{axis}
\end{tikzpicture}
\end{figure}

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Can you post your plot with the tight version? It's really not fun to setup a MWE from scratch just to test a key for you. –  percusse Mar 24 '13 at 23:48
It would be helpful if you composed a fully compilable MWE including \documentclass and the appropriate packages that illustrates the problem. While solving problems can be fun, setting them up is not. Then, those trying to help can simply cut and paste your MWE and get started on solving the problem. –  Peter Grill Mar 25 '13 at 6:40

You can use symbolic x coords:

\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{compat=1.7}
\begin{document}
\begin{tikzpicture}[scale=0.45]
\begin{axis}[
ybar,
xlabel=$\lambda$,ylabel=$\alpha$,
symbolic x coords={2.08,2.09,2.7,4.9,12.8,29.3,64.2},
]
(2.08,10)
(2.09,15)
(2.7,25)
(4.9,22)
(12.8,21)
(29.3,12)
(64.2,17)
};
\end{axis}
\end{tikzpicture}
\end{document}


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thank you very much. it works. i also need to draw a red line, y = 12, with the code:\addplot[red,sharp plot,update limits=false] coordinates {(-16,12) (32,12)};. how should i integrate the red line code with symbolic coords? –  xando Mar 25 '13 at 17:34