The IDLgrROIGroup::Add procedure method adds a region to the region group. Only objects of the IDLgrROI class may be added to the group. The regions in the group must all be of the same type: all points, all paths, or all polygons.
A reference to an instance of the IDLgrROI object class representing the region of interest to add to the group.
Accepts all keywords accepted by the IDLanROIGroup::Add method.