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TranInverse - Inverse transformation defined?   

Description:
This attribute indicates whether a Mapping is able to transform coordinates in the "inverse" direction (i.e. converting output coordinates back into input coordinates). If this attribute is non-zero, the inverse transformation is available. Otherwise, it is not.

Type:
Integer (boolean), readonly.

Class Applicability:
Mapping
All Mappings have this attribute.
CmpMap
The TranInverse attribute value for a CmpMap is given by the boolean AND of the value for each component Mapping.
FrameSet
The TranInverse attribute of a FrameSet applies to the transformation which converts between the FrameSet's current Frame and its base Frame (as specified by the Current and Base attributes). This value is given by the boolean AND of the TranInverse values which apply to each of the individual sub-Mappings required to perform this conversion. The TranInverse attribute value for a FrameSet may therefore change if a new Base or Current Frame is selected.

Notes:
  • An error will result if a Mapping with a TranInverse value of zero is used to transform coordinates in the inverse direction.



next up previous
Next: Unit(axis) - Axis physical units
Up: AST Attribute Descriptions
Previous: TranForward - Forward transformation defined?

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 210
R.F. Warren-Smith & D.S. Berry
30th April 2003
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2003 Central Laboratory of the Research Councils