AST_INTERSECT

Find the point of intersection between two geodesic curves

Description:

This routine finds the coordinate values at the point of intersection between two geodesic curves. Each curve is specified by two points on the curve. It can only be used with 2-dimensional Frames.

For example, in a basic Frame, it will find the point of intersection between two straight lines. But for a SkyFrame it will find an intersection of two great circles.

Invocation

CALL AST_INTERSECT( THIS, A1, A2, B1, B2, CROSS, STATUS )

Arguments

THIS = INTEGER (Given)
Pointer to the Frame.
A1( 2 ) = DOUBLE PRECISION (Given)
An array with one element for each Frame axis (Naxes attribute). This should contain the coordinates of the first point on the first geodesic curve.
A2( 2 ) = DOUBLE PRECISION (Given)
An array with one element for each Frame axis (Naxes attribute). This should contain the coordinates of a second point on the first geodesic curve. It should not be co-incident with the first point.
B1( 2 ) = DOUBLE PRECISION (Given)
An array with one element for each Frame axis (Naxes attribute). This should contain the coordinates of the first point on the second geodesic curve.
B2( 2 ) = DOUBLE PRECISION (Given)
An array with one element for each Frame axis (Naxes attribute). This should contain the coordinates of a second point on the second geodesic curve. It should not be co-incident with the first point.
CROSS( 2 ) = DOUBLE PRECISION (Returned)
An array with one element for each Frame axis in which the coordinates of the required intersection will be returned.
STATUS = INTEGER (Given and Returned)
The global status.

Notes: