Class Name: Time Related Geometry

Superclass - Aggregate Geometry

Definition

An aggregation of Geometry Hierarchies that are differentiated by the Geometry Time Constraints Data link objects attached to the aggregation relationships used to reach the Geometry Hierarchy objects.

Primary Page in DRM Diagram:

• 4

Example

1. Atmospheric forecast data is organized using nested Time Related Geometries.
   

   The Classification Data define what each Time Related Geometry corresponds to. The outer Time Related Geometry corresponds to base forecast times, while the inner Time Related Geometry corresponds to forecast taus.

   In the forecast world, models are run starting at some base starting time, e.g., at 0Z and 12Z. The model then produces forecasts at several deltas after the base starting time, e.g. at 6, 12 ,18, and 24 hours. These are known as forecast taus.

   Consequently, if you run forecast models at 0Z and 12Z, and each produces a 24 hour forecast, you get the following overlap.

    16 Nov                 17 Nov                     18 Nov
    0Z   +6    +12   +18   +24
               12Z   +6   +12    +18    +24
                           0Z    +6     +12    +18    +24
                                  etc.
   

   So to uniquely identify a forecast, you must specify the base forecast time and the delta (tau). This is why nested Time Related Geometry has been used in this example; one Time Related Geometry defines the base forecast time, while its component Time Related Geometry defines the forecast tau.

   Note that this approach is needed only if multiple forecasts with overlapping forecasts are included in the transmittal. If we just use the analysis (0Z) and +6 forecasts from each forecast, then we would have

    16 Nov             17 Nov
    0Z   +6  12Z  +6   0Z   +6   12Z   +6  etc
   

FAQs

Constraints

• No Attribute Conflicts
• Non Crossing Aggregations
• Non Cyclic Aggregations
• Precedence of Attribute Set Index
• Non Crossing Associations
• Color Mapping Restrictions
• Image Mapping Functions and Texture Coordinates
• Distinct Link Objects

Associated by (one-way)(inherited)

• optionally, a Hierarchy Summary Item
• optionally, some Reference Surfaces

Associated with (two-way)(inherited)

• optionally, some Features
• optionally, some Geometry Hierarchies

Composed of (one-way)(inherited)

• optionally, some {ordered} Attribute Set Indices
• optionally, a Classification Data
• optionally, some Property Tables
• optionally, some Property Table References
• optionally, some Property Values
• optionally, a Reference Surface
• optionally, some Sound Instances
• optionally, a Spatial Domain
• optionally, a Bounding Volume
• optionally, a Center of Buoyancy
• optionally, a Center of Mass
• optionally, a Center of Pressure
• optionally, some Collision Volumes
• optionally, a Conformal Behavior
• optionally, a LSR Transformation
• optionally, an Overload Priority Index
• optionally, some Property Descriptions
• optionally, a Stamp Behavior
• optionally, some {ordered} Colors
• optionally, a Light Rendering Properties
• optionally, a Rendering Properties
• optionally, some {ordered} Image Mapping Functions
• optionally, a Rendering Priority Level

Composed of (two-way)(inherited)

• optionally, some Hierarchical Tables
• optionally, some Light Sources

Composed of (two-way)

• one or more Geometry Hierarchies through Geometry Time Constraints Data

Composed of (one-way metadata)(inherited)

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

Component of (two-way)(inherited)

• optionally, some Alternate Hierarchy Related Geometries through Geometry Hierarchy Data
• optionally, some Animation Related Geometries
• optionally, some Classification Related Geometries through Geometry Classification Data
• optionally, an Environment Root
• optionally, some Geometry Separating Plane Relations through Geometry Separating Plane Data
• optionally, a Geometry Model
• optionally, some Level of Detail Related Geometries through Geometry Level of Detail Data
• optionally, some Oct Tree Related Geometries through Geometry Oct Tree Data
• optionally, some Time Related Geometries through Geometry Time Constraints Data
• optionally, some Perimeter Related Geometries through Geometry Perimeter Data
• optionally, some Quad Tree Related Geometries through Geometry Quad Tree Data
• optionally, some Spatial Index Related Geometries through Geometry Spatial Index Data
• optionally, some State Related Geometries through Geometry State Data
• optionally, some Union of Geometry Hierarchies

Inherited Field Elements

Field Elements

Notes

Fields Notes

unique_descendants

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

independent_topologies

 If SE_TRUE, then each 'branch' from this aggregation is its own,
 independent topology.  If SE_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.