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WcsType - FITS-WCS projection type

Description:
This attribute specifies which type of FITS-WCS projection will be performed by a WcsMap. The value is specified when a WcsMap is first created using AST_WCSMAP and cannot subsequently be changed.

The values used are represented by symbolic constants with names of the form "AST__XXX", where "XXX" is the (upper case) 3-character code used by the FITS-WCS "CTYPEi" keyword to identify the projection. For example, possible values are AST__TAN (for the tangent plane or gnomonic projection) and AST__AIT (for the Hammer-Aitoff projection). AST__TPN is an exception in that it is not part of the FITS-WCS standard (it represents a TAN projection with polynomial correction terms as defined in an early draft of the FITS-WCS paper).

Type:
Integer, read-only.
Class Applicability:
WcsMap
All WcsMaps have this attribute.
Notes:
  • For a list of available projections, see the FITS-WCS paper.


next up previous 264
Next: Width(element) - Line width for a Plot element
Up: AST Attribute Descriptions
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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