def subplt_c1_c2(turbine, axarr, c1, c2, c='Blues', xlim=None, ylim=None, xlabel=None, ylabel=None):
    """  hexbin plot of turbine[c1] vs turbine [c2]

    Args:
        turbine(:obj:`pandas dataframe`): data to be plotted
        axarr(:obj:`axis handle`): axis handle
        c1(:obj:`string`): column name of x axis
        c2(:obj:`string`): column name of y axis
        c(:obj:`string` or colormap handle): colormap

    Returns:
        hb(:obj:`plot handle`):
    """
    hb = axarr.hexbin(turbine[c1], turbine[c2], cmap=c, gridsize=128, vmin=0, vmax=8)

    if xlim:
        axarr.set_xlim(xlim)
    if ylim:
        axarr.set_ylim(ylim)
    if xlabel:
        axarr.set_xlabel(xlabel)
    if ylabel:
        axarr.set_ylabel(ylabel)

    return hb