astSkyOffsetMap

Returns a Mapping which goes from absolute coordinates to offset coordinates

Description:

This function returns a Mapping in which the forward transformation transforms a position in the coordinate system given by the System attribute of the supplied SkyFrame, into the offset coordinate system specified by the SkyRef, SkyRefP and SkyRefIs attributes of the supplied SkyFrame.

A UnitMap is returned if the SkyFrame does not define an offset coordinate system.

Synopsis

AstMapping astSkyOffsetMap( AstSkyFrame this )

Parameters:

this
Pointer to the SkyFrame.

Returned Value

astSkyOffsetMap()
Pointer to the returned Mapping.

Notes: