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Symbol(axis) - Axis symbol   

Description:
This attribute specifies a short-form symbol to be used to represent coordinate values for a particular axis of a Frame. This might be used (e.g.) in algebraic expressions where a full description of the axis would be inappropriate. Examples include "RA" and "Dec" (for Right Ascension and Declination).

If a Symbol value has not been set for a Frame axis, then a suitable default is supplied.

Type:
String.

Class Applicability:
Frame
The default Symbol value supplied by the Frame class is the string "<Domain><n>", where <n> is 1, 2, etc. for successive axes, and <Domain> is the value of the Frame's Domain attribute (truncated if necessary so that the final string does not exceed 15 characters). If no Domain value has been set, "x" is used as the <Domain> value in constructing this default string.
SkyFrame
The SkyFrame class re-defines the default Symbol value (e.g. to "RA" or "Dec") as appropriate for the particular celestial coordinate system being represented.
FrameSet
The Symbol 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: System - Coordinate system used to describe positions within the domain
Up: AST Attribute Descriptions
Previous: Style(element) - Line style for a Plot element

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