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A Library for Handling
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Description:
This routine applies a
Mapping
to transform the coordinates of a set of points in one dimension.
Invocation
CALL AST_TRAN1( THIS,
NPOINT, XIN, FORWARD, XOUT, 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 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 coordinates of the output (transformed) points will
be written.
STATUS = INTEGER (Given and Returned)
The global status.
Notes:
Handling of
Huge Pixel Arrays
If the number of points to be transformed exceeds the largest value
that can be represented by a 4-byte integer, then the alternative "
8-byte"
interface for this
function should be used. This alternative interface uses 8 byte integer arguments (instead
of 4-byte). Specifically, the argument NPOINT is changed from type INTEGER to type
INTEGER∗8.
The function name is changed by appending the digit "
8"
to the name. Thus, AST_TRAN1 becomes
AST_TRAN18.
Copyright (C) 2021 East Asian Observatory
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- AST
A Library for Handling
World Coordinate
Systems
in Astronomy - Next→
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