The SEDRIS Data Representation Model
APPENDIX A - Classes
Classification Related Geometry

Class Name: Classification Related Geometry

Superclass - <Aggregate Geometry>

Subclasses

This DRM class is concrete and has no subclasses.

Definition

An instance of this DRM class specifies an aggregation of <Geometry Hierarchy> instances organized according to their ECCs such that each <Geometry Hierarchy> component represents:

  1. a different thematic layer, or
  2. a different classification of <Geometry Representation> instances within a single thematic layer.

Each branch of a <Classification Related Geometry> instance therefore has a <Classification Data> instance associated with it as a link object, specifying its (possibly elaborated) classification.

Primary Page in DRM Diagram:

Secondary Pages in DRM Diagram:

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

Example

  1. A surface area consisting of forest and water is represented as a <Classification Related Geometry> instance with strict_organizing_principle set to SE_TRUE, containing two <Union Of Primitive Geometry> components. The first <Union Of Primitive Geometry> component, containing the forest polygons, is specified through a <Classification Data> link object with a tag value of ECC_FOREST, while the second <Union Of Primitive Geometry> component, containing the water polygons, is specified through a <Classification Data> link object with a tag value of ECC_WATER.

  2. In the first example, suppose a road runs through the forest. Then the forest <Union Of Primitive Geometry> instance can be replaced with another <Classification Related Geometry> instance having two branches, one representing environmental objects classified as ECC_ROAD and the other representing environmental objects classified as ECC_FOREST, and the strict_organizing_principle flag mentioned in the previous example is set to SE_FALSE, because the forest branch at the coarse level contains non-forest (that is, road) geometry.

FAQs

What is the purpose of this class?

The <Classification Related Geometry> class exists to provide a mechanism for hierarchically organizing <Geometry Representation> instances according to their (possibly elaborated) classification.

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 a <Feature Representation> instance and a <Geometry Hierarchy> 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.


Geometry_Hierarchy

An association between two <Geometry Hierarchy> 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.

Associated from Notes


Feature_Representation

An association between a <Feature Representation> instance and a <Geometry Hierarchy> 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.


Geometry_Hierarchy

An association between two <Geometry Hierarchy> 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.


Hierarchy_Summary_Item

An association from a <Hierarchy Summary Item> instance to a <Geometry Hierarchy> instance indicates that the <Hierarchy Summary Item> instance summarizes that <Geometry Hierarchy> instance.


Reference_Surface

An association from a <Reference Surface> instance to a <Geometry Hierarchy> instance indicates that the <Geometry Hierarchy> instance organizes the geometric objects that specify the reference surface geometry of the <Reference Surface> instance.

Composed of Notes


Collision_Volume

In the case where multiple <Collision Volume> components are specified for the <Aggregate Geometry> instance, the union of the volumes thus specified is used in collision detection.


LSR_Transformation

An <Aggregate Geometry> instance can have an <LSR Transformation> component only when the <Aggregate Geometry> instance is within the scope of an LSR 3D SRF.

Fields Notes

unique_descendants

If the value of the unique_descendants field is SE_TRUE, each descendant of this aggregation, that is, each <Geometry Representation> instance that exists in the component tree rooted at the <Aggregate Geometry> instance shall be unique, in the sense that it shall appear in only one branch of this aggregation. If unique_descendants is SE_FALSE, at least one <Geometry 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: June 24, 2007 Copyright © 2007 SEDRIS™