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.
AXIS = INTEGER (Given)
The index of the axis to which the supplied values refer. The first axis has index 1.
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 from the first to the second axis value.

Notes:

• This function will return a " bad" result value (AST__BAD) if any of the input values 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.