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.
Region
All Regions
have this attribute.
The default MeshSize for a CmpRegion is the MeshSize
of its first component Region.
The MeshSize attribute is ignored when forming
a mesh covering the boundary of a Moc. Instead, the mesh will include a point for the
exterior corners of every HEALPix cell (at the order specified by attribute
MaxOrder) that
touches the boundary. Note, this applies only to meshes covering the boundary of the Moc -
the MeshSize attribute is used as normal when forming a mesh covering the area of the
Moc.
The default MeshSize for an Stc is the MeshSize of its encapsulated Region.