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