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Unit(axis)
-
Axis physical units
- Description:
- This attribute contains a textual representation of the physical
units used to represent coordinate values on a particular axis
of a Frame. The astSetActiveUnit function controls how the Unit values
are used.
- Type:
- String.
- Class Applicability:
-
Frame
-
The default supplied by the Frame class is an empty string.
-
SkyFrame
-
The SkyFrame class re-defines the default Unit value (e.g. to
"hh:mm:ss.sss") to describe the character string returned by
the astFormat function when formatting coordinate values.
-
SpecFrame
-
The SpecFrame class re-defines the default Unit value so that it
is appropriate for the current System value. See the System
attribute for details. An error will be reported if an attempt
is made to use an inappropriate Unit.
-
TimeFrame
-
The TimeFrame class re-defines the default Unit value so that it
is appropriate for the current System value. See the System
attribute for details. An error will be reported if an attempt
is made to use an inappropriate Unit (e.g. "km").
-
FrameSet
-
The Unit attribute of a FrameSet axis is the same as that of
its current Frame (as specified by the Current attribute).
- Notes:
- When specifying this attribute by name, it should be
subscripted with the number of the Frame axis to which it
applies.
Next: UnitRadius - SphMap input vectors lie on a unit sphere?
Up: AST Attribute Descriptions
Previous: TranInverse - Inverse transformation defined?
AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 211
R.F. Warren-Smith & D.S. Berry
24th May 2011
E-mail:ussc@star.rl.ac.uk
Copyright (C) 2009 Science \& Technology Facilities Council