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astTran2 - Transform 2-dimensional coordinates   

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

Synopsis:
void astTran2( AstMapping *this, int npoint, const double xin[], const double yin[], int forward, double xout[], double yout[] )

Parameters:
this
Pointer to the Mapping to be applied.
npoint
The number of points to be transformed.
xin
An array of "npoint" X-coordinate values for the input (untransformed) points.
yin
An array of "npoint" Y-coordinate values for the input (untransformed) points.
forward
A non-zero value indicates that the Mapping's forward coordinate transformation is to be applied, while a zero value indicates that the inverse transformation should be used.
xout
An array (with "npoint" elements) into which the X-coordinates of the output (transformed) points will be written.
yout
An array (with "npoint" elements) into which the Y-coordinates of the output (transformed) points will be written.

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



next up previous
Next: astTranN - Transform N-dimensional coordinates
Up: AST Function Descriptions
Previous: astTran1 - Transform 1-dimensional coordinates

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