ISO/IEC 18023-1:200x(E) — Table 6.33 DRM_Classification_Related

Table 6.33 — DRM_Classification_Related_Features

Property

Description

Class

<DRM Classification Related Features>

Superclass

<DRM Aggregate Feature>

Subclass

None.

Definition

An instance of this DRM class is an aggregation of <DRM Feature Hierarchy> instances, organized according to their EDCS Classification Codes (ECCs), such that each component <DRM Feature Hierarchy> instance represents

a different thematic layer, or
a different classification of <DRM Feature> instances within a single thematic layer.

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

Class diagram

Figure 6.33 — DRM_Classification_Related_Features

Inherited field elements

Field name	Range	Field data type
unique_descendants ¹		Boolean
strict_organizing_principle ²		Boolean

Field elements

Field name	Range	Field data type
None

Associated to (one-way) (inherited)

None.

Associated to (one-way)

None.

Associated by (one-way) (inherited)

zero or one <DRM Hierarchy Summary Item> instance

Associated by (one-way)

None.

Associated with (two-way) (inherited)

zero or more <DRM Feature> instances³
zero or more <DRM Geometry Hierarchy> instances⁴
zero or more <DRM Property Grid> instances⁵

Associated with (two-way)

None.

Composed of (two-way) (inherited)

zero or one <DRM Classification Data> instance
zero or more <DRM Label> instances
zero or more {ordered} <DRM Property Set Index> instances
zero or more <DRM Property Table> instances
zero or more <DRM Property Table Reference> instances
zero or more <DRM Property Value> instances
zero or one <DRM Rendering Priority Level> instance
zero or one <DRM Reference Surface> instance
zero or more <DRM Sound Instance> instances
zero or more <DRM Base Level Of Detail Data> instances
zero or more <DRM Colour> instances
zero or more <DRM Feature Topology Hierarchy> instances
zero or more {ordered} <DRM Image Mapping Function> instances⁶
zero or one <DRM Perimeter Data> instance
zero or one <DRM Presentation Domain> instance⁷
zero or more <DRM Property Description> instances
zero or one <DRM Spatial Extent> instance

Composed of (two-way)

one or more <DRM Feature Hierarchy> instances, each with a <DRM Classification Data> link object

Composed of (two-way metadata) (inherited)

zero or one <DRM Access> instance
zero or more <DRM Cross Reference> instances
zero or one <DRM Data Quality> instance
zero or one <DRM Description> instance
zero or one <DRM Time Constraints Data> instance

Composed of (two-way metadata)

None.

Component of (two-way) (inherited)

zero or more <DRM Union Of Features> instances
zero or more <DRM Alternate Hierarchy Related Features> instances, each with a <DRM Hierarchy Data> link object
zero or more <DRM Classification Related Features> instances, each with a <DRM Classification Data> link object
zero or one <DRM Environment Root> instance
zero or one <DRM Feature Model> instance
zero or more <DRM Level Of Detail Related Features> instances, each with a <DRM Base Level Of Detail Data> link object
zero or more <DRM Octant Related Features> instances, each with a <DRM Octant Data> link object
zero or more <DRM Perimeter Related Features> instances, each with a <DRM Perimeter Data> link object
zero or more <DRM Quadrant Related Features> instances, each with a <DRM Quadrant Data> link object
zero or more <DRM Spatial Index Related Features> instances, each with a <DRM Spatial Index Data> link object
zero or more <DRM State Related Features> instances, each with a <DRM State Data> link object
zero or more <DRM Time Related Features> instances, each with a <DRM Time Constraints Data> link object

Component of (two-way)

None.

Constraints

Clarifications

¹ If this value is TRUE, each “descendant” of this aggregation - that is, each <DRM Feature> instance that exists in the component tree rooted at the given <DRM Aggregate Feature> - shall be unique, in the sense that it shall appear in only one “branch” of this aggregation. If unique_descendants is FALSE, at least one <DRM Feature> instance appears in more than one “branch” of the aggregation.

² If this value is TRUE, each “branch” of this aggregation strictly complies with the organizing principle for its particular subclass. If this value is 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.

³ An association between two <DRM Feature> instances indicates that they are alternate representations of the same environmental object.

⁴ An association between a <DRM Geometry Hierarchy> instance and a <DRM Feature> instance indicates that the <DRM Geometry Hierarchy> and the <DRM Feature> are alternate representations of the same environmental object.

⁵ An association between a <DRM Property Grid> instance and a <DRM Feature> instance indicates that the <DRM Feature> and the <DRM Property Grid> (or some specific cell data within that <DRM Property Grid>) are alternate representations of the same environmental object. Each associated <DRM Property Grid> will indicate which is the case.

⁶ 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 <DRM Aggregate Feature> by the consumer. These <DRM Image Mapping Function> instances shall use <DRM Image Anchor> components to specify the mapping.

⁷ This is needed for cases in which an <DRM Aggregate Feature> is significant only for a particular domain, such as radar.

Example(s)

Several thematic layers of features might be grouped using a <DRM Classification Related Features> instance, with each of its components representing a separate thematic layer (such as culture or vegetation). In such a case, the unique_descendants and strict_organizing_principle flags of the <DRM Classification Related Features> instance should be set to TRUE. The <DRM Classification Data> link object associated with each of its components identifies the contents of each thematic layer, and each of the components is an independent topological complex and has a <DRM Feature Topology Hierarchy>.
A region consisting of forest and water is represented as a <DRM Classification Related Features> with strict_organizing_principle set to TRUE, containing two <DRM Union Of Features> components. The first, containing the forest features, has a <DRM Classification Data> link object with tag = ECC_FOREST, while the second, containing the water features, has a <DRM Classification Data> link object with tag = ECC_WATER.
Considering the first example, suppose that roads run through the forest. The forest <DRM Union Of Features> can then be replaced with another <DRM Classification Related Features> having 2 branches, one classified as ECC_ROAD and the other as ECC_FOREST, and the strict_organizing_principle flag in example 1's <DRM Classification Related Features> would set to FALSE, because the forest branch at the coarse level contains non-forest (in this case, road) features.
A large collection of features might be organized using a <DRM Classification Related Features> instance, with multiple component <DRM Union Of Features> instances, containing cultural, vegetation, and surface drainage features, respectively.