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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
astGetRegionMesh 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) 2014 Science & Technology Facilities Council
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- AST
A Library for
Handling
World Coordinate Systems
in Astronomy - Next→
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