\documentclass{article}

\usepackage{pgfplots}
\usepgfplotslibrary{groupplots}
\pgfplotsset{compat=1.8}

\begin{document}
\pgfplotsset{
	xmin=0,
	xmax=1,
	ymin=0,
	ymax=1,
}

\begin{tikzpicture}
\begin{axis}[
    scale only axis,
    view={0}{90},
    data cs=polar,
    point meta min=-5,
    point meta max= 5,
    colorbar,
    ]
\end{axis}
\end{tikzpicture}

\begin{tikzpicture}
\begin{groupplot}[group style={group size=2 by 2, xticklabels at=edge bottom, yticklabels at=edge left,vertical sep=2cm,},
    scale only axis,
    view={0}{90},
    data cs=polar,
    point meta min=-5,
    point meta max= 5,
  ]
\nextgroupplot[
    colorbar,
    ]
\end{groupplot}
\end{tikzpicture}

\end{document}
