Create dictionary containing default ColumnDataSource glyph to data
        mappings.

def get_default_mapping(self, z, cmapper):
        """Create dictionary containing default ColumnDataSource glyph to data
        mappings.

        """

        map_annular = dict(x=self.max_radius, y=self.max_radius,
                           inner_radius="inner_radius",
                           outer_radius="outer_radius",
                           start_angle="start_angle",
                           end_angle="end_angle",
                           fill_color={'field': z, 'transform': cmapper})

        map_seg_label = dict(x="x", y="y", text="text",
                             angle="angle", text_align="center")

        map_ann_label = dict(x="x", y="y", text="text",
                             angle="angle", text_align="center",
                             text_baseline="bottom")

        map_xmarks = dict(xs="xs", ys="ys")

        map_ymarks = dict(x= self.max_radius, y=self.max_radius,
                          start_angle=0, end_angle=2*np.pi, radius="radius")

        return {'annular_wedge_1': map_annular,
                'text_1': map_seg_label,
                'text_2': map_ann_label,
                'multi_line_1': map_xmarks,
                'arc_1': map_ymarks}