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

Class Name: Quadrant 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> components in which each <Geometry Hierarchy> component represents a branch of a quadrant. The quadrant represented by a branch is specified by the <Quadrant Data> link object associated with that branch. The bounding region that the <Geometry Hierarchy> components occupy is defined by the <Spatial Extent> component of the <Quadrant Related Geometry> instance.

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 representation of a region of terrain that is organized into quadrants, where the SE_QUADRANT_RIGHT_FRONT quadrant consists of ocean, and the other three quadrants consist of the terrain bordering the ocean. The ocean quadrant is not represented in the producer's system. The region is represented in the DRM by a <Quadrant Related Geometry> instance with three <Union Of Primitive Geometry> instances as depicted in Figure 6.51. (Since the remaining quadrant had no <Polygon> instances, it was not represented.)

    Quadrant Related Geometry, Example 1

    Figure 51 — <DRM Quadrant Related Geometry> ocean example

  2. Consider a set of environmental data that is represented in a transmittal by a <Quadrant Related Geometry> instance. The SE_QUADRANT_LEFT_BACK quadrant of the environmental data is a <Union Of Primitive Geometry> instance aggregated by the <Quadrant Related Geometry> instance as depicted in Figure 6.52:

    Quadrant Related Geometry, Example 2

    Figure 52 — <DRM Quadrant Related Geometry> example

FAQs

If a <Quadrant Related Geometry> instance has less than four components, why is the data being represented using a <Quadrant Related Geometry> instance at all?

A <Quadrant Related Geometry> instance is used when the environmental data to be represented logically lends itself to a quadrant related organization. However, since a given quadrant within such an organization might not contain <Primitive Geometry> instances, a <Quadrant Related Geometry> instance can have fewer than four components.

Where is the <Spatial Extent> component?

A <Quadrant Related Geometry> instance automatically has a <Spatial Extent> component, because it is a <Geometry Hierarchy> instance.

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: July 26, 2006 Copyright © 2006 SEDRIS