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AST_TRAN2 - Transform 2-dimensional coordinates   

Description:
This routine applies a Mapping to transform the coordinates of a set of points in two dimensions.

Invocation:
CALL AST_TRAN2( THIS, NPOINT, XIN, YIN, FORWARD, XOUT, YOUT, STATUS )

Arguments:
THIS = INTEGER (Given)
Pointer to the Mapping to be applied.
NPOINT = INTEGER (Given)
The number of points to be transformed.
XIN( NPOINT ) = DOUBLE PRECISION (Given)
An array of X-coordinate values for the input (untransformed) points.
YIN( NPOINT ) = DOUBLE PRECISION (Given)
An array of Y-coordinate values for the input (untransformed) points.
FORWARD = LOGICAL (Given)
A .TRUE. value indicates that the Mapping's forward coordinate transformation is to be applied, while a .FALSE. value indicates that the inverse transformation should be used.
XOUT( NPOINT ) = DOUBLE PRECISION (Returned)
An array into which the X-coordinates of the output (transformed) points will be written.
YOUT( NPOINT ) = DOUBLE PRECISION (Returned)
An array into which the Y-coordinates of the output (transformed) points will be written.
STATUS = INTEGER (Given and Returned)
The global status.

Notes:
  • The Mapping supplied must have the value 2 for both its Nin and Nout attributes.



next up previous
Next: AST_TRANN - Transform N-dimensional coordinates
Up: AST Routine Descriptions
Previous: AST_TRAN1 - Transform 1-dimensional coordinates

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 210
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