The SEDRIS Data Representation Model
APPENDIX A - Classes
Union Of Geometry Hierarchy

Class Name: Union Of Geometry Hierarchy

Superclass - <Union Of Geometry>

Subclasses

This DRM class is concrete and has no subclasses.

Definition

An instance of this DRM class serves to organize <Geometry Hierarchy> instances for which no other organizing principle is suitable.

Primary Page in DRM Diagram:

Secondary Pages in DRM Diagram:

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

Example

  1. An antenna assembly is contained in a weather protection enclosure. Visually, only the opaque enclosure can be seen. But at microwave frequencies, the enclosure is invisible and only the antenna can be seen. The entire structure is contained in a <Union Of Geometry Hierarchy> instance. What the radar sees is modelled with a radar cross-section (RCS) <Property Table> instance. The algorithm (or field measurements) that computed the RCS table used axes that do not match the SRF (world or model as the case may be). Therefore, RCS axes of azimuth and elevation angle are misused unless some <Reference Vector> instances are attached to the entire <Union Of Geometry Hierarchy> instance.

FAQs

See <Union Of Geometry>.

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
SE_Union_Reason union_reason; 11
SE_Ordering_Reason ordering_reason; 12

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.

union_reason

The union_reason field specifies the reason why the <Union Of Geometry> instance was created to organize its components.

ordering_reason

The ordering_reason field specifies whether the ordering of the <Geometry Representation> components of the <Union Of Geometry> instance is semantically significant and, if so, what that significance is.


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Last updated: July 26, 2006 Copyright © 2006 SEDRIS