#### Description:

This attribute is used when attempting to write a FrameSet to a FitsChan using a foreign encoding. It specifies the maximum departure from linearity allowed on any axis within the mapping from pixel coordinates to Intermediate World Coordinates. It is expressed in units of pixels. If an axis of the Mapping is found to deviate from linearity by more than this amount, the write operation fails. If the linearity test succeeds, a linear approximation to the mapping is used to determine the FITS keyword values to be placed in the FitsChan.

The default value is one tenth of a pixel.

Type:

  Floating point.

#### Applicability

##### FitsChan

All FitsChans have this attribute.
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