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Description:
This
attribute controls how many points are used when creating a mesh of points covering the boundary or
volume of a
Region. Such a mesh is returned by the
AST_GETREGIONMESH method. The
boundary mesh is also used when testing for overlap between two Regions: each point in the
bomdary mesh of the first Region is checked to see if it is inside or outside the second
Region. Thus, the reliability of the overlap check depends on the value assigned to this
attribute. If the value used is very low, it is possible for overlaps to go unnoticed. High values
produce more reliable results, but can result in the overlap test being very slow. The default
value is 200 for two dimensional Regions and 2000 for three or more dimensional Regions
(this attribute is not used for 1-dimensional regions since the boundary of a simple 1-d
Region can only ever have two points). A value of five is used if the supplied value is
less than five.
Type:
Integer. Applicability
Region
All Regions have this attribute.
The default MeshSize for a CmpRegion is the MeshSize of its first component
Region.
The default MeshSize for an Stc is the MeshSize of its encapsulated Region.
Copyright (C) 2017 East Asian Observatory
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- AST
A Library for Handling
World Coordinate
Systems
in Astronomy - Next→
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