- ←Prev
- AST
A Library for Handling
World Coordinate Systems
in Astronomy - Next→
- TOC ↑
Description:
This function
returns a pointer to a new
Polygon that contains a subset of the vertices in the supplied Polygon. The
subset is chosen so that the returned Polygon is a good approximation to the supplied
Polygon, within the limits specified by the supplied parameter values. That is, the density of
points in the returned Polygon is greater at points where the curvature of the boundary of
the supplied Polygon is greater.
Invocation
RESULT = AST_DOWNSIZE( THIS, MAXERR,
MAXVERT, STATUS )
Arguments
THIS = INTEGER (Given)
Pointer to the Polygon.
MAXERR = DOUBLE PRECISION (Given)
The maximum allowed discrepancy between the
supplied and returned Polygons, expressed as a geodesic distance within the Polygon’
s coordinate frame. If this is zero or less, the returned Polygon will have the number of
vertices specified by MAXVERT.
MAXVERT = INTEGER (Given)
The maximum allowed
number of vertices in the returned Polygon. If this is less than 3, the number of vertices in
the returned Polygon will be the minimum needed to achieve the maximum discrepancy
specified by MAXERR.
STATUS = INTEGER (Given and Returned)
The global status.
Returned Value
AST_DOWNSIZE = INTEGER
Pointer to the new Polygon.
Notes:
Copyright (C) 2021 East Asian Observatory
- ←Prev
- AST
A Library for Handling
World Coordinate
Systems
in Astronomy - Next→
- TOC ↑