The DRM is Composed of ...
Geometry type objects Physical/surface representations of real world objects (ie: 3D polygons, patches, lines, and points)
Feature type objects Represent higher level abstraction of real world objects (ie: areal, linear, and point features)
Topology Concise, mathematical definition of inter-Feature or inter-Geometry object relationships
Attributes (ie: location, time, color, sound, width, etc.)
Libraries Store copies of any instanceable object
Explicit relationships Among feature objects, geometry objects, or between feature and geometry objects
Organizational schemes Allows for well-described hierarchical configuration of geometry and feature objects