The SEDRIS Data Representation Model
APPENDIX A - Classes
Alternate Hierarchy Related Features

Class Name: Alternate Hierarchy Related Features

Superclass - <Aggregate Feature>

Subclasses

This DRM class is concrete and has no subclasses.

Definition

An instance of this DRM class specifies an aggregation of <Feature Hierarchy> components, in which each <Feature Hierarchy> component is an alternate representation of the same environmental entity, and the corresponding <Hierarchy Data> link object indicates why that particular alternate representation was provided.

Primary Page in DRM Diagram:

Secondary Pages in DRM Diagram:

This class appears on only one page of the DRM class diagram.

Example

  1. Consider a collection of <Feature Representation> instances representing a specific spatial region, for which there is a requirement that the <Feature Representation> instances shall be efficiently accessible both by location and by classification (such as ECC_ROAD, ECC_RIVER, ECC_VEGETATION).

    To satisfy this requirement, the data provider has chosen to use an <Alternate Hierarchy Related Features> instance with two components, in which one component (in this example, a <Quadrant Related Features> component) organizes the <Feature Representation> instances spatially, while a second component (a <Classification Related Features> component) organizes the <Feature Representation> instances by ECC. The <Alternate Hierarchy Related Features> instance is related to its <Quadrant Related Features> component through a <Hierarchy Data> link object with alternate_representation_reason containing the string "accessibility by location". The <Alternate Hierarchy Related Features> instance is related to its <Classification Related Features> component through a <Hierarchy Data> link object with alternate_representation_reason containing the string "accessibility by classification".

FAQs

What is the purpose of this class?

This class allows a single collection of <Feature Representation> instances to be hierarchically organized in two or more different ways. In one component, the <Feature Representation> instances might be organized spatially, while in another component they might be organized by classification. Each branch of an instance of this class provides a different access path to the same objects, where each branch is organized to be efficient with respect to a different access pattern.

Constraints

Associated to (one-way) (inherited)

Associated by (one-way) (inherited)

Composed of (two-way) (inherited)

Composed of (two-way)

Composed of (two-way metadata) (inherited)

Component of (two-way) (inherited)

Inherited Field Elements

SE_Boolean unique_descendants; 9
SE_Boolean strict_organizing_principle; 10

Notes

Associated to Notes


Feature_Representation

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


Geometry_Hierarchy

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


Property_Grid

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

Associated from Notes


Feature_Representation

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


Geometry_Hierarchy

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


Property_Grid

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

Composed of Notes


Image_Mapping_Function

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


Presentation_Domain

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

Fields Notes

unique_descendants

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

strict_organizing_principle

If the value of the strict_organizing_principle field is SE_TRUE, each branch of this aggregation strictly complies with the organizing principle for its particular subclass. If this value is SE_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.


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Last updated: July 26, 2006 Copyright © 2006 SEDRIS