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Side-effects of Changing the Unit attribute

If an Axis has an active Unit attribute, changing its value (either by setting a new value or by clearing it so that the default value is re-instated) may cause the Label and Symbol attributes to be changed accordingly. For instance, if an Axis has Unit, Label and Symbol of ``Hz'', ``Frequency'' and ``nu'', then changing its Unit attribute to ``log(Hz)'' will cause AST to change its Label and Symbol to ``log(Frequency)'' and ``Log(nu)''. These changes are only made if the Unit attribute is active, and a Mapping can be found from the old units to the new units. On the other hand, changing the Unit from ``Hz'' to ``MHz'' would not cause any change to the Label or Symbol attributes.



next up previous
Next: Celestial Coordinate Systems (SkyFrames)
Up: The Unit Attribute
Previous: The Syntax for Unit Strings

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