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Changes Introduced in V4.4

The following describes the most significant changes which occurred in the AST library between versions V4.3 and V4.4:

  1. The astFindFrame function can now be used to search a CmpFrame for an instance of a more specialised class of Frame (SkyFrame, TimeFrame, SpecFrame, DSBSpecFrame or FluxFrame). That is, if an instance of one of these classes is used as the ``template'' when calling astFindFrame, and the ``target'' being searched is a CmpFrame (or a FrameSet in which the current Frame is a CmpFrame), then the component Frames within the CmpFrame will be searched for an instance of the supplied template Frame, and, if found, a suitable Mapping (which will include a PermMap to select the required axes from the CmpFrame) will be returned by astFindFrame. Note, for this to work, the MaxAxes and MinAxes attributes of the template Frame must be set so that they cover a range that includes the number of axes in the target CmpFrame.

  2. The SkyFrame, SpecFrame, DSBSpecFrame, TimeFrame and FluxFrame classes now allow the MaxAxes and MinAxes attributes to be set freely to any value. In previous versions of AST, any attempt to change the value of MinAxes or MaxAxes was ignored, resulting in them always taking the default values.

  3. The DSBSpecFrame class has a new attribute called AlignSB that specifies whether or not to take account of the SideBand attributes when aligning two DSBSpecFrames using astConvert.

  4. The Frame class has a new attribute called Dut1 that can be used to store a value for the difference between the UT1 and UTC timescales at the epoch referred to by the Frame.

  5. The number of digits used to format the Frame attributes ObsLat and ObsLon has been increased.

  6. The use of the SkyFrame attribute AlignOffset has been changed. This attribute is used to control how two SkyFrames are aligned by astConvert. If the template and target SkyFrames both have a non-zero value for AlignOffset, then alignment occurs between the offset coordinate systems (that is, a UnitMap will always be used to align the two SkyFrames).

  7. The Plot class has a new attribute called ForceExterior that can be used to force exterior (rather than interior) tick marks to be produced. By default, exterior ticks are only produced if this would result in more than 3 tick marks being drawn.

  8. The TimeFrame class now supports conversion between angle based timescales such as UT1 and atomic based timescales such as UTC.



next up previous 264
Next: Changes Introduced in V4.5
Up: Changes and New Features
Previous: Changes Introduced in V4.3

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 211
R.F. Warren-Smith & D.S. Berry
25th February 2013
E-mail:starlink@jiscmail.ac.uk

Copyright (C) 2014 Science \& Technology Facilities Council