The SEDRIS Data Representation Model
APPENDIX A - Classes
Level Of Detail Related Features

Class Name: Level Of Detail Related Features

Superclass - <Aggregate Feature>

Subclasses

This DRM class is concrete and has no subclasses.

Definition

An instance of this DRM class is an aggregation of <Feature Hierarchy> objects in which each component <Feature Hierarchy> is an alternate representation of the same entity at a different level of detail. Each component <Feature Hierarchy> is a collection of <Feature> objects with a different, possibly overlapping, <Base Level Of Detail Data> value, representing alternatives that should be used at different viewing ranges, map scales, spatial resolution, and so on.

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 forested area could be represented at two levels of detail using a <Level Of Detail Related Features> instance, with two component <Union of Features> instances having different scale ranges, each containing a single <Areal Feature>. The <Areal Feature> to be used at smaller scales would be simpler than the <Areal Feature> to be used at larger scales.

  2. In the previous example, a third component <Union Of Features> could be added to be used at even larger scales, where the single <Areal Feature> is replaced by a large number of <Point Feature> instances representing individual trees.

FAQs

No FAQs supplied.

Constraints

Associated by (one-way)(inherited)

Associated with (two-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; (notes)
SE_Boolean strict_organizing_principle; (notes)

Field Elements

SE_LOD_Data_Type lod_data_type;

Notes

Associated with Notes


Feature

 An association between two <Feature> instances indicates
 that they are alternate representations of the same
 environmental object.

Geometry_Hierarchy

 An association between a <Geometry Hierarchy> instance and a
 <Feature> instance indicates that the <Geometry Hierarchy>
 and the <Feature> are alternate representations of the same
 environmental object.

Property_Grid

 An association between a <Property Grid> instance and a
 <Feature> instance indicates that the <Feature> and the <Property Grid>
 (or some specific cell data within that <Property Grid>) are
 alternate representations of the same environmental object.
 Each associated <Property Grid> will indicate which is the case.

Composed of Notes


Image_Mapping_Function

 This relationship exists to support "attributes for derived objects."
 That is, these components are used only to specify texture mapping
 information for geometry that is to be derived from the
 <Aggregate Feature> by the consumer. These <Image Mapping Function>
 instances shall use <Image Anchor> components to specify the mapping.

Presentation_Domain

 This is needed for cases in which an <Aggregate Feature> is
 significant only for a particular domain, such as radar.

Fields Notes


unique_descendants

 If this value is SE_TRUE, each 'descendant' of this aggregation -
 that is, each <Feature> instance that exists in the component tree
 rooted at the given <Aggregate Feature> - 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 <Feature> instance
 appears in more than one 'branch' of the aggregation.

strict_organizing_principle

 If this value 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: May 15, 2003 Copyright © 2003 SEDRIS™