Property
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Description
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Class
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- <DRM Time Related Geometry>
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Superclass
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Subclass
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Definition
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An instance of this DRM class is an aggregation of
<DRM Geometry Hierarchy> components in which
each branch is a representation of the same environmental entity at
a different point in time, as indicated by the corresponding
<DRM Time Constraints Data> link object.
The time_data_type field
specifies the subclass of <DRM Base Time Data> of which
each <DRM Time Constraints Data> link object
in the given organization is to be composed.
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Class diagram
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Figure 6.349 —
DRM_Time_Related_Geometry
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Inherited field elements
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Field elements
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Default field values
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Default field values for DRM_Time_Related_Geometry
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Associated to (one-way) (inherited) |
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Associated to (one-way) |
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Associated by (one-way) (inherited) |
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Associated by (one-way) |
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Associated with (two-way) (inherited) |
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Associated with (two-way) |
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Composed of (two-way) (inherited) |
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Composed of (two-way) |
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Composed of (two-way metadata) (inherited) |
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Composed of (two-way metadata) |
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Component of (two-way) (inherited) |
- zero or more <DRM Alternate Hierarchy Related Geometry> instances, each through the use of a <DRM Hierarchy Data> link object
- zero or more <DRM Animation Related Geometry> instances
- zero or more <DRM Classification Related Geometry> instances, each through the use of a <DRM Classification Data> link object
- zero or one <DRM Environment Root> instance
- zero or one <DRM Geometry Model> instance
- zero or more <DRM LOD Related Geometry> instances, each through the use of a <DRM Base LOD Data> link object
- zero or more <DRM Octant Related Geometry> instances, each through the use of a <DRM Octant Data> link object
- zero or more <DRM Perimeter Related Geometry> instances, each through the use of a <DRM Perimeter Data> link object
- zero or more <DRM Quadrant Related Geometry> instances, each through the use of a <DRM Quadrant Data> link object
- zero or more <DRM Separating Plane Relations> instances, each through the use of a <DRM Separating Plane Data> link object
- zero or more <DRM Spatial Index Related Geometry> instances, each through the use of a <DRM Spatial Index Data> link object
- zero or more <DRM State Related Geometry> instances, each through the use of a <DRM State Data> link object
- zero or more <DRM Time Related Geometry> instances, each through the use of a <DRM Time Constraints Data> link object
- zero or more <DRM Union Of Geometry Hierarchy> instances
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Component of (two-way) |
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Constraints
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Clarifications
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1An association between a
<DRM Feature Representation>
instance and a
<DRM Geometry Hierarchy> instance
indicates that the environmental object(s) that they
represent have the semantic relationship indicated by
the <DRM Base Association Data>
link object on the association relationship.
2An association between two
<DRM Geometry Hierarchy> instances
indicates that the environmental object(s) that they
represent have the semantic relationship indicated by
the <DRM Base Association Data>
link object on the association relationship.
3An association between a
<DRM Feature Representation>
instance and a
<DRM Geometry Hierarchy> instance
indicates that the environmental object(s) that they
represent have the semantic relationship indicated by
the <DRM Base Association Data>
link object on the association relationship.
4An association between two
<DRM Geometry Hierarchy> instances
indicates that the environmental object(s) that they
represent have the semantic relationship indicated by
the <DRM Base Association Data>
link object on the association relationship.
5An association from a
<DRM Hierarchy Summary Item>
instance to a <DRM Geometry Hierarchy>
instance indicates that the
<DRM Hierarchy Summary Item> instance
summarizes that <DRM Geometry Hierarchy>
instance.
6An association from a
<DRM Reference Surface> instance to a
<DRM Geometry Hierarchy> instance indicates
that the <DRM Geometry Hierarchy>
instance organizes the geometric objects that specify
the reference surface geometry of the
<DRM Reference Surface> instance.
7In the case where multiple
<DRM Collision Volume> components are
specified for the
<DRM Aggregate Geometry> instance,
the union
of the volumes thus specified is used in collision detection.
8A <DRM Aggregate Geometry> instance can have
a <DRM LSR Transformation> component only when the
<DRM Aggregate Geometry> instance is within
the scope of an LSR 3D SRF.
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Example(s)
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Consider atmospheric forecast data organized using nested
<DRM Time Related Geometry> instances as depicted in
Figure 6.350:
Figure 6.350 — <DRM Time Related Geometry> atmospheric forecast example
The <DRM Classification Data> instances specify to what each
<DRM Time Related Geometry> instance corresponds. The outer
<DRM Time Related Geometry> instance corresponds to
base forecast times, while the inner <DRM Time Related Geometry>
instance corresponds to forecast taus.
In the forecast world, models are run starting at some base starting time
(for example, at 0Z and 12Z). The model then produces forecasts at
several deltas after the base starting time (for example, at 6, 12,
18, and 24 hours). These are known as forecast taus.
Consequently, forecast models are run at 0Z and 12Z, and each produces
a 24 hour forecast, the following overlap is obtained.
16 Nov 17 Nov 18 Nov
0Z +6 +12 +18 +24
12Z +6 +12 +18 +24
0Z +6 +12 +18 +24
....
To uniquely identify a forecast, the base forecast time and the
delta (tau) are required. This is why nested
<DRM Time Related Geometry> instances
have been used in this example; one
<DRM Time Related Geometry> instance
defines the base forecast time, while its
<DRM Time Related Geometry> component defines
the forecast tau.
This approach is needed only if multiple forecasts with
overlapping forecasts are included in the transmittal. If instead
the analysis (0Z) and +6 forecasts from each forecast are used,
the following is obtained.
16 Nov 17 Nov
0Z +6 12Z +6 0Z +6 12Z +6 ...
Consider a <DRM Model> instance representing a deciduous tree.
The colour of the leaves of the tree depends on the time of year,
or season. Consequently, a data provider to whom this is important
organizes a tree <DRM Model> instance using a
<DRM Time Related Geometry> instance along the lines
depicted in Figure 6.351. Only the autumn
representation of the <DRM Model> instance
is shown, but other branches are present for the other seasons.
Figure 6.351 — <DRM Time Related Geometry> deciduous tree example
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