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- Description:
This attribute indicates whether a Mapping is able to transform
coordinates in the "forward" direction (i.e. converting input
coordinates into output coordinates). If this attribute is
non-zero, the forward transformation is available. Otherwise, it
is not.
- Type:
- Integer (boolean), read-only.
- Class Applicability:
-
Mapping
-
All Mappings have this attribute.
-
CmpMap
-
The TranForward attribute value for a CmpMap is given by the
boolean AND of the value for each component Mapping.
-
FrameSet
-
The TranForward attribute of a FrameSet applies to the
transformation which converts between the FrameSet's base
Frame and its current Frame (as specified by the Base and
Current attributes). This value is given by the boolean AND
of the TranForward values which apply to each of the
individual sub-Mappings required to perform this conversion.
The TranForward 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 TranForward value of
zero is used to transform coordinates in the forward direction.
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Up: AST Attribute Descriptions
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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