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AST_TRANN - Transform N-dimensional coordinates   

Description:
This routine applies a Mapping to transform the coordinates of a set of points in an arbitrary number of dimensions. It is the appropriate routine to use if the coordinates are not purely 1- or 2-dimensional and are stored in a single array (which they need not fill completely).

Invocation:
CALL AST_TRANN( THIS, NPOINT, NCOORD_IN, INDIM, IN, FORWARD, NCOORD_OUT, OUTDIM, OUT, STATUS )

Arguments:
THIS = INTEGER (Given)
Pointer to the Mapping to be applied.
NPOINT = INTEGER (Given)
The number of points to be transformed.
NCOORD_IN = INTEGER (Given)
The number of coordinates being supplied for each input point (i.e. the number of dimensions of the space in which the input points reside).
INDIM = INTEGER (Given)
The number of elements along the first dimension of the IN array (which contains the input coordinates). This value is required so that the coordinate values can be correctly located if they do not entirely fill this array. The value given should not be less than NPOINT.
IN( INDIM, NCOORD_IN ) = DOUBLE PRECISION (Given)
An array containing the coordinates of the input (untransformed) points. These should be stored such that the value of coordinate number COORD for input point number POINT is found in element IN(POINT,COORD).
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.
NCOORD_OUT = INTEGER (Given)
The number of coordinates being generated by the Mapping for each output point (i.e. the number of dimensions of the space in which the output points reside). This need not be the same as NCOORD_IN.
OUTDIM = INTEGER (Given)
The number of elements along the first dimension of the OUT array (which will contain the output coordinates). This value is required so that the coordinate values can be correctly located if they will not entirely fill this array. The value given should not be less than NPOINT.
OUT( OUTDIM, NCOORD_OUT ) = DOUBLE PRECISION (Returned)
An array into which the coordinates of the output (transformed) points will be written. These will be stored such that the value of coordinate number COORD for output point number POINT will be found in element OUT(POINT,COORD).
STATUS = INTEGER (Given and Returned)
The global status.

Notes:
  • If the forward coordinate transformation is being applied, the Mapping supplied must have the value of NCOORD_IN for its Nin attribute and the value of NCOORD_OUT for its Nout attribute. If the inverse transformation is being applied, these values should be reversed.



next up previous
Next: AST_UINTERP - Perform sub-pixel interpolation on a grid of data
Up: AST Routine Descriptions
Previous: AST_TRAN2 - Transform 2-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