SipReplace

Replace SIP inverse transformation?

Description:

This attribute is a boolean value which specifies how SIP keywords should be handled when reading a FITS-WCS encoded header using the astRead function. See http://irsa.ipac.caltech.edu/data/SPITZER/docs/files/spitzer/shupeADASS.pdf for more information about SIP headers. If SipReplace is non-zero, then any SIP keywords describing the inverse transformation (i.e. from WCS to pixel coordinates) are ignored. Instead a new inverse transformation is found by performing a fit to the forward transformation. The SipReplace attribute can be set to zero to prevent this happening. If SipReplace is zero, any SIP keywords describing the inverse transformation are used as supplied, rather than being replaced using a new fit. The default value is 1.
Type:
Integer (boolean).

Applicability

FitsChan
All FitsChans have this attribute.