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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.
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 up previous
Next: Warnings - Controls the issuing of warnings about various conditions
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
30th April 2003
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2003 Central Laboratory of the Research Councils