Abstract Class Name: Aggregate Geometry

Superclass - Geometry Hierarchy

Subclasses

• Alternate Hierarchy Related Geometry
• Animation Related Geometry
• Classification Related Geometry
• Continuous Level of Detail Related Geometry
• Level of Detail Related Geometry
• Oct Tree Related Geometry
• Perimeter Related Geometry
• Quad Tree Related Geometry
• Separating Plane Related Geometry
• Spatial Index Related Geometry
• State Related Geometry
• Time Related Geometry
• Union of Geometry

Definition

A collection of Primitive Geometry or Geometry Hierarchies, possibly including Geometry Model Instances and/or Property Grid Hook Points. In most cases each of the individual components is explicitly labeled by a link data object. The various subclasses provide different mechanisms for organizing Geometry, which include:

• ALTERNATE_HIERARCHY:
  Each of the components is a Geometry Hierarchy with a different Geometry Hierarchy Data value, representing different ways of organizing the same collection of Geometry.

• ANIMATION: Each of the components is a Geometry Hierarchy, representing a different frame in an animation sequence. This mechanism has no counterpart on the Feature side.

• CLASSIFICATION:
  Each of the components is a Geometry Hierarchy with a different Geometry Classification Data value, representing different thematic layers, or different classifications of Geometry (e.g., roads, railroads) within a single thematic layer.

• CONTINUOUS_LEVEL_OF_DETAIL:
  Each of the components is either a Union of Primitive Geometry (usually a collection of Polygons), or a set of fragmented Polygons that represent the terrain at a finer level of detail at close range (or alternatively, with a coarser level of detail at long range). Used to represent continuous terrain or continuous adaptive terrain. This mechanism has no counterpart on the Feature side.

• LEVEL_OF_DETAIL:
  Each of the components is a Geometry Hierarchy with a different, possibly overlapping, Geometry Level of Detail Data value, representing alternatives that should be used at different viewing ranges or map scales.

• OCT_TREE:
  Each of the components is a Geometry Hierarchy that is located within a different cell of an octree, as identified by its Geometry Oct Tree Data value.

• PERIMETER:
  Each of the components is a Geometry Hierarchy that is located within a different cell of an irregular spatial index, as defined by its Geometry Perimeter Data value.

• QUAD_TREE:
  Each of the components is a Geometry Hierarchy that is located within a different cell of an quadtree, as identified by its Geometry Quad Tree Data value.

• SEPARATING_PLANE:
  Each of the components is a Geometry Hierarchy that is on either the True or False side of the associated Separating Plane (whether a component is on the True or False side is indicated by the data contained within the Geometry Separating Plane Data class association for that component). This mechanism has no counterpart on the Feature side.

• SPATIAL_INDEX:
  Each of the components is a Geometry Hierarchy that is located within a different cell of a regularly spaced spatial index grid.

• STATE:
  Each of the components is a Geometry Hierarchy with a different Geometry State Data value, representing alternatives that should be used when the Aggregate Geometry is in different states.

• TIME:
  Each of the components is a Geometry Hierarchy with a different, possibly overlapping, Geometry Time Constraints Data value, representing alternatives that should be used during different time periods.

• UNION_OF_GEOMETRY_HIERARCHY:
  Each of the components is a Geometry Hierarchy. The reason for organizing them into separate components is not specified. This mechanism's counterpart on the Feature side is Union of Features.

• UNION_OF_PRIMITIVE_GEOMETRY: Each of the components is a Primitive Geometry, e.g. a bag of Polygons. Primitive Geometry can be included in a transmittal only by means of a Union of Primitive Geometry. This mechanism's counterpart on the Feature side is Union of Features.

Primary Page in DRM Diagram:

• 4

Secondary Pages in DRM Diagram:

• 3
• 18
• 21

Example

1. A 500 meter by 500 meter patch of gridded terrain.
2. A 10 Km by 20 km triangulated irregular network of Polygons.
3. A populated rectangular region that is one node of a quad tree of Aggregate Geometry objects.
4. Atmosphere over a certain region is stored for two different times of day.

Constraints

• No Attribute Conflicts
• Non Crossing Aggregations
• Non Cyclic Aggregations
• Precedence of Attribute Set Index
• Non Crossing Associations
• Color Mapping Restrictions
• Image Mapping Functions and Texture Coordinates

Associated by (one-way)(inherited)

• optionally, a Hierarchy Summary Item
• optionally, some Reference Surfaces

Associated with (two-way)(inherited)

• optionally, some Features
• optionally, some Geometry Hierarchies

Composed of (one-way)(inherited)

• optionally, some {ordered} Attribute Set Indices
• optionally, a Classification Data
• optionally, some Property Tables
• optionally, some Property Table References
• optionally, some Property Values
• optionally, a Reference Surface
• optionally, some Sound Instances
• optionally, a Spatial Domain

Composed of (one-way)

• optionally, a Bounding Volume
• optionally, a Center of Buoyancy
• optionally, a Center of Mass
• optionally, a Center of Pressure
• optionally, some Collision Volumes
• optionally, a Conformal Behavior
• optionally, a LSR Transformation
• optionally, an Overload Priority Index
• optionally, some Property Descriptions
• optionally, a Stamp Behavior
• optionally, some {ordered} Colors
• optionally, a Light Rendering Properties
• optionally, a Rendering Properties
• optionally, some {ordered} Image Mapping Functions
• optionally, a Rendering Priority Level

Composed of (two-way)

• optionally, some Hierarchical Tables
• optionally, some Light Sources

Composed of (one-way metadata)(inherited)

• optionally, a Time Constraints Data
• optionally, an Access
• optionally, some Browse Graphics
• optionally, some Cross References
• optionally, a Data Quality
• optionally, a Keywords
• optionally, a Point of Contact

Component of (two-way)(inherited)

• optionally, some Alternate Hierarchy Related Geometries through Geometry Hierarchy Data
• optionally, some Animation Related Geometries
• optionally, some Classification Related Geometries through Geometry Classification Data
• optionally, an Environment Root
• optionally, some Geometry Separating Plane Relations through Geometry Separating Plane Data
• optionally, a Geometry Model
• optionally, some Level of Detail Related Geometries through Geometry Level of Detail Data
• optionally, some Oct Tree Related Geometries through Geometry Oct Tree Data
• optionally, some Time Related Geometries through Geometry Time Constraints Data
• optionally, some Perimeter Related Geometries through Geometry Perimeter Data
• optionally, some Quad Tree Related Geometries through Geometry Quad Tree Data
• optionally, some Spatial Index Related Geometries through Geometry Spatial Index Data
• optionally, some State Related Geometries through Geometry State Data
• optionally, some Union of Geometry Hierarchies

Field Elements

Notes

Fields Notes

unique_descendants

 If SE_TRUE, then for any object that exists 'below' this aggregation,
 each object will appear in only one 'branch' of this aggregation.
 If SE_FALSE, then objects may appear in multiple 'branches' of this
 aggregation.

independent_topologies

 If SE_TRUE, then each 'branch' from this aggregation is its own,
 independent topology.  If SE_FALSE, then all of the branches exist
 within the same topology.

strict_organizing_principle

 If true, then each 'branch' strictly follows the rules of this
 aggregation.  If false, then each 'branch' might bend the rules a bit.
 For example, if this is a spatial aggregation, than a value of true
 indicates that objects will *not* cross the spatial extents defined
 by this aggregation relationship, and a value of false indicates
 that objects might cross those bounds.  For another example, if this
 is a time-based aggregation, then a value of true indicates that all
 branches will only contain data valid for the times specified for
 each branch, and a value of false indicates that the branches have
 the option of including data that falls outside of the specified
 time ranges for that branch.