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AST_AXDISTANCE
-
Find the distance between two axis values
- Description:
This routine returns a signed value representing the axis increment
from axis value v1 to axis value v2.
For a simple Frame, this is a trivial operation returning the
difference between the two axis values. But for other derived classes
of Frame (such as a SkyFrame) this is not the case.
- Invocation:
RESULT = AST_AXDISTANCE( THIS, AXIS, V1, V2, STATUS )
- Arguments:
-
THIS = INTEGER (Given)
-
Pointer to the Frame.
-
V1 = DOUBLE PRECISION (Given)
-
The first axis value.
-
V2 = DOUBLE PRECISION (Given)
-
The second axis value.
-
STATUS = INTEGER (Given and Returned)
-
The global status.
- Returned Value:
-
AST_AXDISTANCE = DOUBLE PRECISION
-
The distance between the two axis values.
- Notes:
-
This function will return a "bad" result value (AST__BAD) if
any of the input vaues has this value.
-
A "bad" value will also be returned if this function is
invoked with STATUS set to an error value, or if it should fail for
any reason.
Next: AST_AXOFFSET - Add an increment onto a supplied axis value
Up: AST Routine Descriptions
Previous: AST_AXANGLE - Returns the angle from an axis, to a line through two points
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