# image_resid¶

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

Display the residuals (data - model) for a data set in the image viewer.

This function displays the residuals (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.

Raises

sherpa.utils.err.IdentifierErr – If the data set does not exist or a source expression has not been set.

get_resid_image()

Return the data used by image_resid.

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_ratio()

Display the ratio (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

1

http://ds9.si.edu/site/Home.html

Examples

Display the residuals for the default data set.

>>> image_resid()


Display the residuals for data set 2 in a new frame so that the data in the current frame is not destroyed. The new data will be displayed in a single frame (i.e. the only data shown by the viewer).

>>> image_resid(2, newframe=True)


Display the residuals for data sets ‘i1’ and ‘i2’ side by side:

>>> image_resid('i1')
>>> image_resid('i2', newframe=True, tile=True)