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Representing Coordinate Systems (Frames)  

An AST Frame is an Object that is used to represent a coordinate system. Contrast this with a Mapping ([*]), which is used to describe how to convert between coordinate systems. The two concepts are complementary and we will see how they work together in [*].

In this section we will discuss only basic Frames, which represent Cartesian coordinate systems. More specialised types of Frame (e.g. the SkyFrame, which represents celestial coordinate systems, and the SpecFrame, which represents spectral coordinate systems) are covered later ([*] and [*]) and, naturally, inherit the properties and behaviour of the simple Frames discussed here.



 

next up previous
Next: The Frame Model
Up: AST A Library for Handling World Coordinate Systems in Astronomy
Previous: Simplifying Compound Mappings

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