# contour_ratio¶

sherpa.astro.ui.contour_ratio(id=None, **kwargs)

Contour the ratio of data to model.

The ratio image is formed by dividing the data by the current model, including any PSF. The preferences are the same as contour_data.

Parameters
• id (int or str, optional) – The data set that provides the data and model. If not given then the default identifier is used, as returned by get_default_id.

• replot (bool, optional) – Set to True to use the values calculated by the last call to contour_ratio. The default is False.

• overcontour (bool, optional) – If True then add the data to an exsiting plot, otherwise create a new contour plot. The default is False.

get_ratio_contour()

Return the data used by contour_ratio.

get_default_id()

Return the default data set identifier.

contour()

Create one or more plot types.

sherpa.astro.ui.set_coord()

Set the coordinate system to use for image analysis.

Examples

Plot the ratio from the default data set:

>>> contour_ratio()


Overplot the ratio on the residuals:

>>> contour_resid('img')
>>> contour_ratio('img', overcontour=True)