def spatial_subset_dfr(dfr, bbox):
    """
    Selects data within spatial bbox. bbox coords must be given as
    positive values for the Northern hemisphere, and negative for
    Southern. West and East both positive - Note - the method is
    naive and will only work for bboxes fully fitting in the Eastern hemisphere!!!
    Args:
        dfr - pandas dataframe
        bbox - (list) [North, West, South, East]
    Returns:
        pandas dataframe
    """
    dfr = dfr[(dfr['latitude'] < bbox[0]) &
                            (dfr['latitude'] > bbox[2])]
    dfr = dfr[(dfr['longitude'] > bbox[1]) &
                            (dfr['longitude'] < bbox[3])]
    return dfr