Table 6.4 — DRM_Aggregate_Feature

Property

Description

Class
  • <DRM Aggregate Feature>

Superclass

Subclass

Definition

An instance of this DRM class specifies a collection of <DRM Primitive Feature> instances and/or <DRM Feature Hierarchy> instances organized according to some organizing principle specific to the particular subclass of <DRM Aggregate Feature> being considered.

For most subclasses of <DRM Aggregate Feature>, each individual branch of the aggregation is explicitly identified through a distinct link object. The various subclasses provide different mechanisms for organizing <DRM Feature Representation> instances, which include:

alternate hierarchy:

Each branch is a <DRM Feature Hierarchy> instance through a different <DRM Hierarchy Data> link object, representing a different way of organizing the same underlying collection of <DRM Feature Representation> instances.

classification:

Each branch is a <DRM Feature Hierarchy> instance through a different <DRM Classification Data> link object, representing a different thematic layer, or a different classification of <DRM Feature Representation> instances (e.g., roads, railroads) within a single thematic layer.

level of detail:

Each branch is a <DRM Feature Hierarchy> instance through a distinct (but possibly overlapping), <DRM Base LOD Data> link object, representing an alternative that is to be used at a specified level of detail.

octant:

The <DRM Aggregate Feature> instance represents an octant-related organization, where each branch is a <DRM Feature Hierarchy> instance representing an octant, as identified through its <DRM Octant Data> link object.

perimeter:

Each branch is a <DRM Feature Hierarchy> instance that is located within a different cell of an irregular spatial index, as defined through its <DRM Perimeter Data> link object.

quadrant:

The <DRM Aggregate Feature> instance represents a quadrant related organization, in which each branch is a <DRM Feature Hierarchy> instance representing a quadrant, as identified through its <DRM Quadrant Data> link object.

spatial index:

The <DRM Aggregate Feature> instance represents a regularly spaced spatial index grid, in which each branch is a <DRM Feature Hierarchy> instance representing a different cell within the spatial index.

state:

The <DRM Aggregate Feature> instance represents the different states of an environmental object for a specified EAC. Each branch represents the environmental object for a different state value of the specified EAC. Each branch is a <DRM Feature Hierarchy> instance through a <DRM State Data> link object that corresponds to the specified state value.

time:

The <DRM Aggregate Feature> instance represents an environmental object that has different representations for different time periods. Each branch is a <DRM Feature Hierarchy> instance through a distinct (though possibly overlapping) <DRM Time Constraints Data> link object representing an alternative that shall be used for the time period specified through its <DRM Time Constraints Data> link object.

union:

Each branch is a <DRM Feature Representation> instance. The reason for organizing them into separate components is specified by the union_reason field.

If the value of the unique_descendants field is TRUE, each descendant shall be unique in the sense that it shall appear in only one branch of this aggregation. Each descendant is a <DRM Feature Representation> instance within the component tree rooted at the <DRM Aggregate Feature> instance. If unique_descendants is FALSE, at least one <DRM Feature Representation> instance appears in more than one branch of the aggregation.

If the value of the strict_organizing_principle field is TRUE, each branch of this aggregation strictly complies with the organizing principle for its particular subclass. If this value is FALSE, at least one branch does not strictly comply with the given organizing principle. See the organizing principle constraint for each specific subclass for details.

Class diagram

Figure 6.3 — DRM_Aggregate_Feature

Inherited field elements

Field name

Range

Field data type

None

    

Field elements

Field name

Range

Field data type

unique_descendants

 

Boolean

strict_organizing_principle

 

Boolean

Default field values

Default field values for DRM_Aggregate_Feature

Associated to (one-way) (inherited)

Associated to (one-way)
  • None.

Associated by (one-way) (inherited)

Associated by (one-way)
  • None.

Associated with (two-way) (inherited)
  • None.

Associated with (two-way)
  • None.

Composed of (two-way) (inherited)

Composed of (two-way)

Composed of (two-way metadata) (inherited)

Composed of (two-way metadata)
  • None.

Component of (two-way) (inherited)

Component of (two-way)
  • None.

Constraints

Clarifications

1An association between two <DRM Feature Representation> instances indicates that the environmental object(s) that they represent have the semantic relationship indicated by the <DRM Base Association Data> link object on the association relationship.

2An association between a <DRM Geometry Hierarchy> instance and a <DRM Feature Representation> instance indicates that the environmental object(s) that they represent have the semantic relationship indicated by the <DRM Base Association Data> link object on the association relationship.

3An association between a <DRM Property Grid> instance and a <DRM Feature Representation> instance indicates that the environmental object(s) represented by the <DRM Feature Representation> instance and the <DRM Property Grid> instance (or some specific cell data within that <DRM Property Grid> instance) have the semantic relationship indicated by the <DRM Base Association Data> link object on the association relationship. Each associated <DRM Property Grid> instance indicates whether the entire <DRM Property Grid> instance or only some specific cell data within it is participating in the relationship in question.

4An association between two <DRM Feature Representation> instances indicates that the environmental object(s) that they represent have the semantic relationship indicated by the <DRM Base Association Data> link object on the association relationship.

5An association between a <DRM Geometry Hierarchy> instance and a <DRM Feature Representation> instance indicates that the environmental object(s) that they represent have the semantic relationship indicated by the <DRM Base Association Data> link object on the association relationship.

6An association between a <DRM Property Grid> instance and a <DRM Feature Representation> instance indicates that the environmental object(s) represented by the <DRM Feature Representation> instance and the <DRM Property Grid> instance (or some specific cell data within that <DRM Property Grid> instance) have the semantic relationship indicated by the <DRM Base Association Data> link object on the association relationship. Each associated <DRM Property Grid> instance indicates whether the entire <DRM Property Grid> instance or only some specific cell data within it is participating in the relationship in question.

7The <DRM Image Mapping Function> components support texture mapping information for geometry that is to be derived from the <DRM Aggregate Feature> instance by the consumer. These <DRM Image Mapping Function> instances shall use <DRM Image Anchor> components to specify the mapping.

8A <DRM Presentation Domain> component is needed for <DRM Aggregate Feature> instances that are significant only for a particular domain, such as radar.

Example(s)
  • See concrete subclasses for examples.