Class Name: Quad Tree Related Features

Superclass - Aggregate Feature

Definition

An aggregation of Feature Hierarchies in which each component Feature Hierarchy represents a branch of a Quad Tree. The quadrant represented by a branch is specified by the Feature Quad Tree Data associated with that branch. The bounding region that the Feature Hierarchy components occupy is defined by the Spatial Domain of the Quad Tree Related Features.

Primary Page in DRM Diagram:

• 8

Example

1. Consider a region of terrain that is organized into quadrants, where the upper-right 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 SEDRIS by a Quad Tree Related Features with 3 component Union of Features. (Since the remaining quadrant had no Features, it was not represented.)
   

FAQs

If a Quad Tree Related Features has less than 4 components, why is the data being organized under a Quad Tree Related Features at all?

A Quad Tree Related Features is used when an object in the hierarchy contains spatial components that occupy a certain quadrant. These quadrants might not contain Primitive Features, which is why this class can have less than four components.

Where is the Spatial Domain component?

Quad Tree Related Features automatically has a Spatial Domain component, because it is a Feature. Unlike Features in general, however, Quad Tree Related Features has a business rule stating that the Spatial Domain component is mandatory.

Constraints

• Image Mapping Functions and Texture Coordinates
• No Attribute Conflicts
• Non Crossing Aggregations
• Non Crossing Associations
• Precedence of Attribute Set Index
• Non Cyclic Aggregations
• Distinct Link Objects
• Quad Tree Spatial Domain

Associated by (one-way)(inherited)

• optionally, a Hierarchy Summary Item

Associated with (two-way)(inherited)

• optionally, some Features
• optionally, some Geometry Hierarchies
• optionally, some Property Grids

Composed of (one-way)(inherited)

• optionally, some {ordered} Attribute Set Indices
• optionally, a Classification Data
• optionally, some Colors
• optionally, some {ordered} Image Mapping Functions (notes)
• optionally, some Labels
• optionally, some Property Tables
• optionally, some Property Table References
• optionally, some Property Values
• optionally, a Rendering Priority Level
• optionally, a Spatial Domain
• optionally, a Reference Surface
• optionally, some Sound Instances
• optionally, some Property Descriptions

Composed of (two-way)(inherited)

• optionally, some Topology Hierarchies

Composed of (two-way)

• a bounded set of Feature Hierarchies[1..4] through Feature Quad Tree Data

Composed of (one-way metadata)(inherited)

• optionally, an Access
• optionally, some Browse Graphics
• optionally, some Cross References
• optionally, a Data Quality
• optionally, a Keywords
• optionally, a Point of Contact
• optionally, a Time Constraints Data

Component of (two-way)(inherited)

• optionally, some Union of Features
• optionally, some Alternate Hierarchy Related Features through Feature Hierarchy Data
• optionally, some Classification Related Features through Feature Classification Data
• optionally, an Environment Root
• optionally, a Feature Model
• optionally, some Time Related Features through Feature Time Constraints Data
• optionally, some Level of Detail Related Features through Feature Level of Detail Data
• optionally, some Oct Tree Related Features through Feature Oct Tree Data
• optionally, some Perimeter Related Features through Feature Perimeter Data
• optionally, some Quad Tree Related Features through Feature Quad Tree Data
• optionally, some Spatial Index Related Features through Feature Spatial Index Data
• optionally, some State Related Features through Feature State Data

Inherited Field Elements

Notes

Composed of Notes

Image_Mapping_Function

 Added to support "attributes for derived objects."
 That is, these components are used only to specify
 texture mapping information for geometry that
 is derived from the <Feature> by the consumer.
 These <Image Mapping Functions> must use
 <Image Anchor> components to specify the mapping.

Fields Notes

unique_descendants

 If true, then for any object that exists 'below' this aggregation,
 each object will appear in only one 'branch' of this aggregation.
 If false, then objects may appear in multiple 'branches' of this
 aggregation.

independent_topologies

 If true, then each 'branch' from this aggregation is its own,
 independent topology.  If false, then all of the branches exist
 within the same topology.

strict_organizing_principle

 If true, then each 'branch' strictly follows the rules of this
 aggregation.  If false, then each 'branch' might bend the rules a bit.
 For example, if this is a spatial aggregation, than a value of true
 indicates that objects will *not* cross the spatial extents defined
 by this aggregation relationship, and a value of false indicates
 that objects might cross those bounds.  For another example, if this
 is a time-based aggregation, then a value of true indicates that all
 branches will only contain data valid for the times specified for
 each branch, and a value of false indicates that the branches have
 the option of including data that falls outside of the specified
 time ranges for that branch.