Creating a colormap in tikz/pgfplots, no axis

I'd like to replicate this colormap in TiKz or pgfplots. Let me clarify, I don't need a plot of any kind, these are screen-shots from another application. But since the labels on the pic below are poor I'd like to make it more professional.

So far I have this rubbish:

Is there a way to cut out the adjoining plot altogether and put my own tick labels on the contour?

\documentclass[tikz,border={12pt,12pt}]{standalone}
\usepackage{pgfplots}
\usetikzlibrary{plotmarks}
\begin{document}
\begin{tikzpicture}

\begin{axis}[hide axis,colorbar,colormap/jet,
colorbar style={yshift=-2cm,
xtick={18,22,26,30,34,38,42,45},
xticklabel={18,22,26,30,34,38,42,45},
rotate=270,
yticklabel pos=left,
yticklabel style={anchor=south},},
]
{
};
\end{axis}
\end{tikzpicture}

\end{document}

-

You can make the axis take up no space by setting scale only axis, width=0pt, height=0pt, hide axis.

To be able to set the range of the colorbar, you have to provide a dummy plot. Then you can set point meta min and point meta max to control the range:

\documentclass{standalone}
\usepackage{pgfplots}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
hide axis,
scale only axis,
height=0pt,
width=0pt,
colormap/jet,
colorbar horizontal,
point meta min=18,
point meta max=45,
colorbar style={
width=10cm,
xtick={18,20,25,...,45}
}]

@HCAI: Sure. Just set colorbar sampled before colorbar horizontal, and then set samples=<number> in the colorbar style. – Jake Jun 20 '13 at 11:45
@HCAI: You can change the width in the colorbar style options. That doesn't affect the number of samples. Is that what you mean? – Jake Jun 20 '13 at 14:22