ISO/IEC 18023-1:200x(E) — Table 6.255 DRM_Spatial_Index_Related

Table 6.255 — DRM_Spatial_Index_Related_Geometry

Property

Description

Class

<DRM Spatial Index Related Geometry>

Superclass

<DRM Aggregate Geometry>

Subclass

None.

Definition

An instance of this DRM class specifies a spatially indexed related aggregation representing a collection of <DRM Geometry Hierarchy> components in which each <DRM Geometry Hierarchy> component represents a different tile within this aggregation. The <DRM Spatial Index Data> link object corresponding to each <DRM Geometry Hierarchy> component indicates which tile it represents.

If the value of the sparse field is FALSE, all column and row entries are present; otherwise one or more entries are not present.

The column_count field specifies the number of cells along the primary axis.

The row_count field specifies the number of cells along the secondary axis.

The column_width field specifies the length of a cell in the given unit along the primary axis.

The row_width field specifies the length of a cell in the given unit along the secondary axis.

The spacing_unit field specifies the unit of measurement for column_width and row_width.

Class diagram

Figure 6.314 — DRM_Spatial_Index_Related_Geometry

Inherited field elements

Field name	Range	Field data type
unique_descendants		Boolean
strict_organizing_principle		Boolean

Field elements

Field name	Range	Field data type
sparse		Boolean
column_count		Integer_Positive
row_count		Integer_Positive
column_width		Long_Float
row_width		Long_Float
spacing_unit		Spatial_Index_Spacing_Unit

Default field values

Default field values for DRM_Spatial_Index_Related_Geometry

Associated to (one-way) (inherited)

zero or more <DRM Feature Representation> instances, each through the use of a <DRM Base Association Data> link object¹
zero or more <DRM Geometry Hierarchy> instances, each through the use of a <DRM Base Association Data> link object²

Associated to (one-way)

None.

Associated by (one-way) (inherited)

zero or more <DRM Feature Representation> instances, each through the use of a <DRM Base Association Data> link object³
zero or more <DRM Geometry Hierarchy> instances, each through the use of a <DRM Base Association Data> link object⁴
zero or one <DRM Hierarchy Summary Item> instance⁵
zero or more <DRM Reference Surface> instances⁶

Associated by (one-way)

None.

Associated with (two-way) (inherited)

None.

Associated with (two-way)

None.

Composed of (two-way) (inherited)

zero or one <DRM Classification Data> instance
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 Reference Surface> instance
zero or more <DRM Sound Instance> instances
zero or more <DRM Base LOD Data> instances
zero or one <DRM Bounding Volume> instance
zero or more <DRM Camera Point> instances
zero or more <DRM Collision Volume> instances⁷
zero or more <DRM Colour> instances
zero or one <DRM Conformal Behaviour> instance
a bounded set of 0..3 <DRM Geometric Centre> instances
zero or more <DRM Geometry Topology Hierarchy> instances
zero or more {ordered} <DRM Image Mapping Function> instances
zero or one <DRM Light Rendering Properties> instance
zero or more <DRM Light Source> instances
zero or one <DRM LSR Transformation> instance⁸
zero or one <DRM Overload Priority Index> instance
zero or one <DRM Perimeter Data> instance
zero or one <DRM Presentation Domain> instance
zero or more <DRM Property Description> instances
zero or one <DRM Rendering Priority Level> instance
zero or one <DRM Rendering Properties> instance
zero or one <DRM Spatial Extent> instance
zero or one <DRM Stamp Behaviour> instance

Composed of (two-way)

one or more <DRM Geometry Hierarchy> instances, each through the use of a <DRM Spatial Index Data> link object
one <DRM Location> instance⁹

Composed of (two-way metadata) (inherited)

zero or one <DRM Time Constraints Data> instance
zero or one <DRM Data Quality> instance
zero or one <DRM Identification> instance

Composed of (two-way metadata)

None.

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

Component of (two-way)

None.

Constraints

Clarifications

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.

⁹The <DRM Location> component is the origin of the collection, which is the lower left corner.

Example(s)

Consider a <DRM Spatial Index Related Geometry> instance with row_count = 1, column_count = 4, row_width = 1000 metres, column_width = 1000 metres. For simplicity, each of the four branches of the <DRM Spatial Index Related Geometry> instance in this example is a <DRM Union Of Primitive Geometry> instance as depicted in Figure 6.315.

Figure 6.315 — <DRM Spatial Index Related Geometry> example

Since the origin of the collection (its lower left corner, the <DRM TM Augmented 3D Location> component) is (0, 0, 0), the coverages of the branches are:
1. from (0, 0) to (1000, 1000)
2. from (1000, 0) to (2000, 1000)
3. from (2000, 0) to (3000, 1000)
4. from (3000, 0) to (4000, 1000)
NOTE 1 A <DRM Spatial Index Related Geometry> instance does not specify the range of z/height/elevation values.
Consider a triangular <DRM Polygon> instance in branch #2 of this aggregation, with <DRM Vertex> components having <DRM Location> instances (1995, 0, 0), (2005, 0, 0) (2005, 10, 0).
Since this <DRM Polygon> instance crosses the boundary between branch #2 and branch #3, this <DRM Spatial Index Related Geometry> instance’s strict_organizing_principle is set to FALSE.
Consider a <DRM Environment Root> instance representing a terrain surface that is a mix of grids and polygons, organized by spatial indexing into nine cells as depicted in Figure 6.316.

Figure 6.316 — <DRM Spatial Index Related Geometry> spatial indexing

All cells except H are grids (represented in the DRM as <DRM Property Grid> instances) captured at one level of detail. Cell H consists of <DRM Polygon> instances as depicted in Figure 6.317.

Figure 6.317 — <DRM Spatial Index Related Geometry> grid and polygon example

NOTE 2 The components of the <DRM Spatial Index Related Geometry> instance are not ordered; the <DRM Spatial Index Data> link objects are used to identify the individual tiles.