Class Name: Union Of Geometry Topology

Superclass - <Geometry Topology Hierarchy>

Subclasses

Definition

An instance of this DRM class is a collection of the <Geometry Topology> instances that form a complete topological surface.

Primary Page in DRM Diagram:

• 11

Secondary Pages in DRM Diagram:

Example

1. A terrain region representing a road network might be broken up into four rectangular tiles. While the <Polygon> instances representing roads are allowed to extend across the tile boundaries, the <Geometry Topology> instances that are located within each tile are organized into separate <Union Of Geometry Topology> instances to support access by spatial location.

FAQs

What is the purpose of this class?

This class allows <Geometry Topology> instances to be grouped in an arbitrary manner. It is used to ensure that all <Geometry Topology> instances, particularly those that are not directly associated with any <Geometry Representation> instance, have at least one containing DRM object.

Constraints

• <<Publishable Object>>
• <<Perimeter Related Organizing Principle>>
• <<Union Organizing Principle>>

Composed of (two-way)

• one or more <Geometry Topology> instances

Component of (two-way) (inherited)

• zero or more <Aggregate Geometry> instances

Component of (two-way)

• zero or one <Perimeter Related Geometry Topology> instance, each through the use of a <Perimeter Data> link object
• zero or one <Spatial Index Related Geometry Topology> instance, each through the use of a <Spatial Index Data> link object

Inherited Field Elements

Notes

Fields Notes

geometry_topology_level

The geometry_topology_level field specifies the level of geometry topology that is present within the hierarchy represented by the <Geometry Topology Hierarchy> instance.