# image_ratio¶

sherpa.astro.ui.image_ratio(id=None, newframe=False, tile=False)

Display the ratio (data/model) for a data set in the image viewer.

This function displays the ratio data/model for a data set.

The image viewer is automatically started if it is not already open.

Parameters: id (int or str, optional) – The data set. If not given then the default identifier is used, as returned by get_default_id. newframe (bool, optional) – Create a new frame for the data? If False, the default, then the data will be displayed in the current frame. tile (bool, optional) – Should the frames be tiles? If False, the default, then only a single frame is displayed. sherpa.utils.err.IdentifierErr – If the data set does not exist or a source expression has not been set.

get_ratio_image()
Return the data used by image_ratio.
image_close()
Close the image viewer.
image_data()
Display a data set in the image viewer.
image_fit()
Display the data, model, and residuals for a data set in the image viewer.
image_model()
Display the model for a data set in the image viewer.
image_open()
Open the image viewer.
image_resid()
Display the residuals (data - model) for a data set in the image viewer.
image_source()
Display the model for a data set in the image viewer.

Notes

Image visualization is optional, and provided by the DS9 application [1].

References

Examples

Display the ratio (data/model) for the default data set.

>>> image_ratio()