A PointList object is a specialised type of RegionRegion which represents a collection of points in a coordinate FrameFrame.
If supplied, the uncertainty Region must be of a class for which all instances are centro-symetric (e.g. BoxBox, CircleCircle, EllipseEllipse, etc.) or be a PrismPrism containing centro-symetric component Regions. A deep copy of the supplied Region will be taken, so subsequent changes to the uncertainty Region using the supplied pointer will have no effect on the created Box. Alternatively, a NULL ObjectObject pointer may be supplied, in which case a default uncertainty is used equivalent to a box 1.0E-6 of the size of the bounding box of the PointList being created.
The uncertainty Region has two uses: 1) when the astOverlapastOverlap function compares two Regions for equality the uncertainty Region is used to determine the tolerance on the comparison, and 2) when a Region is mapped into a different coordinate system and subsequently simplified (using astSimplifyastSimplify), the uncertainties are used to determine if the transformed boundary can be accurately represented by a specific shape of Region.