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Permute - Permute axis order?

Description:
This attribute is a boolean value which controls how a Frame behaves when it is used (by AST_FINDFRAME) as a template to match another (target) Frame. It specifies whether the axis order of the target Frame may be permuted in order to obtain a match.

If the template's Permute value is zero, it will match a target only if it can do so without changing the order of its axes. Otherwise, it will attempt to permute the target's axes as necessary.

The default value is 1, so that axis permutation will be attempted.

Type:
String.
Class Applicability:
Frame
All Frames have this attribute. However, the Frame class effectively ignores this attribute and behaves as if it has the value 1. This is because the axes of a basic Frame are not distinguishable and will always match any other Frame whatever their order.
SkyFrame
Unlike a basic Frame, the SkyFrame class makes use of this attribute.
FrameSet
The Permute attribute of a FrameSet is the same as that of its current Frame (as specified by the Current attribute).


next up previous 264
Next: PolarLong - The longitude value to assign to either pole
Up: AST Attribute Descriptions
Previous: PcdCen(axis) - Centre coordinates of pincushion/barrel distortion

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 210
R.F. Warren-Smith & D.S. Berry
24th May 2011
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2009 Science \& Technology Facilities Council