Computing bboxes for STC geometries.
A bbox coming out of this module is a 4-tuple of (ra0, de0, ra1, de1) in ICRS degrees.
(You’re right, this should be part of the dm classes; but it’s enough messy custom code that I found it nicer to break it out).
GCSegment(long1, lat1, long2, lat2)[source]¶
A great circle segment on a sphere. It is assumed that it’s no larger than pi.
Construction is long,lat, long, lat in rad (or use the fromDegrees class method.
Very small (<1e-8 rad, say) segments are not supported. You should probably work in the tangential plane on that kind of scale.
returns a sequence of bounding boxes for this great circle segment.
Actually, the sequence contains one box for a segment that does not cross the stitching line, two boxes for those that do.
iterates over the bboxes of the areas within ast.
bboxes are (ra0, de0, ra1, de1) in ICRS degrees.
getHeading(long1, lat1, long2, lat2)[source]¶
returns the initial heading when going from one spherical position to another along a great circle.
Everything is in rad, angle is counted north over east.