/*
 * ENUM: SE_OCTANT_ENUM
 *
 *   Used by <Oct Tree Data> to specify which octant of an Oct Tree
 *   is represented by the associated <Feature Hierarchy> (for an
 *   <Oct Tree Related Features>) or <Geometry Hierarchy> (for an
 *   <Oct Tree Related Geometry>).
 *
 *   The numbering of the octants is based upon the region Oct Trees
 *   described in The Design and Analysis of Spatial Data Structures, by
 *   Hanan Samet, Addison-Wesley, 1990.
 */