Class Name: Alternate Hierarchy Related Features
Subclasses
This DRM class is concrete and has no subclasses.
Definition
An instance of this DRM class specifies an aggregation of
<Feature Hierarchy> components, in which each
<Feature Hierarchy> component is
an alternate representation of the same environmental entity,
and the corresponding <Hierarchy Data> link object
indicates why that particular alternate representation was provided.
Primary Page in DRM Diagram:
Secondary Pages in DRM Diagram:
This class appears on only one page of the DRM class diagram.
Example
Consider a collection of
<Feature Representation> instances
representing a specific spatial region, for which there is a
requirement that the
<Feature Representation> instances shall
be efficiently accessible both by location and by classification
(such as ECC_ROAD, ECC_RIVER,
ECC_VEGETATION).
To satisfy this requirement, the data provider has chosen to use
an <Alternate Hierarchy Related Features> instance with two
components, in which one component (in this example, a
<Quadrant Related Features> component) organizes the
<Feature Representation> instances
spatially, while a second component (a
<Classification Related Features> component) organizes the
<Feature Representation> instances by ECC.
The <Alternate Hierarchy Related Features> instance is
related to its <Quadrant Related Features> component
through a <Hierarchy Data> link object with
alternate_representation_reason
containing the string "accessibility by location". The
<Alternate Hierarchy Related Features> instance is related
to its <Classification Related Features> component through a
<Hierarchy Data> link object with
alternate_representation_reason
containing the string "accessibility by classification".
FAQs
-
What is the purpose of this class?
This class allows a single collection of
<Feature Representation>
instances to be hierarchically organized in two or more different ways.
In one component, the
<Feature Representation> instances
might be organized spatially, while in another component they might be
organized by classification. Each branch of an instance of this class
provides a different access path to the same objects, where each branch
is organized to be efficient with respect to a different access pattern.
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)
Notes
Associated to Notes
An association between two
<Feature Representation> 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.
An association between a
<Geometry Hierarchy> instance and a
<Feature Representation> 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.
An association between a
<Property Grid> instance and a
<Feature Representation> instance
indicates that the environmental object(s) represented by the
<Feature Representation> instance
and the <Property Grid> instance
(or some specific cell data within that
<Property Grid> instance) have the
semantic relationship indicated by the
<Base Association Data> link object
on the association relationship. Each associated
<Property Grid> instance indicates
whether the entire <Property Grid>
instance or only some specific cell data within it is participating
in the relationship in question.
Associated from Notes
An association between two
<Feature Representation> 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.
An association between a
<Geometry Hierarchy> instance and a
<Feature Representation> 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.
An association between a
<Property Grid> instance and a
<Feature Representation> instance
indicates that the environmental object(s) represented by the
<Feature Representation> instance
and the <Property Grid> instance
(or some specific cell data within that
<Property Grid> instance) have the
semantic relationship indicated by the
<Base Association Data> link object
on the association relationship. Each associated
<Property Grid> instance indicates
whether the entire <Property Grid>
instance or only some specific cell data within it is participating
in the relationship in question.
Composed of Notes
The <Image Mapping Function> components
support texture mapping information
for geometry that is to be derived from the
<Aggregate Feature> instance
by the consumer.
These <Image Mapping Function>
instances shall use <Image Anchor>
components to specify the mapping.
A <Presentation Domain> component is needed for
<Aggregate Feature> instances that are
significant only for a particular domain, such as radar.
Fields Notes
If the value of the
unique_descendants
field is SE_TRUE, each
descendant shall be unique in the sense that it shall
appear in only one branch of this aggregation.
Each descendant is a <Feature Representation> instance
within the component tree rooted at the
<Aggregate Feature> instance.
If unique_descendants
is SE_FALSE, at least one
<Feature Representation> instance
appears in more than one branch of the aggregation.
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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Next: Alternate Hierarchy Related Geometry.
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