next up previous 264
Next: TranMap - Mapping with specified forward and inverse transformations
Up: AST Class Descriptions
Previous: TimeFrame - Time coordinate system description


TimeMap - Sequence of time coordinate conversions

Description:
A TimeMap is a specialised form of 1-dimensional Mapping which can be used to represent a sequence of conversions between standard time coordinate systems.

When a TimeMap is first created, it simply performs a unit (null) Mapping. Using the astTimeAdd function, a series of coordinate conversion steps may then be added. This allows multi-step conversions between a variety of time coordinate systems to be assembled out of a set of building blocks.

For details of the individual coordinate conversions available, see the description of the astTimeAdd function.

Constructor Function:
astTimeMap (also see astTimeAdd)
Inheritance
The TimeMap class inherits from the Mapping class.
Attributes
The TimeMap class does not define any new attributes beyond those which are applicable to all Mappings.
Functions
In addition to those functions applicable to all Mappings, the following function may also be applied to all TimeMaps:

  • astTimeAdd: Add a time coordinate conversion to an TimeMap


next up previous 264
Next: TranMap - Mapping with specified forward and inverse transformations
Up: AST Class Descriptions
Previous: TimeFrame - Time coordinate system description

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 211
R.F. Warren-Smith & D.S. Berry
24th May 2011
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2009 Science \& Technology Facilities Council