The SEDRIS Data Representation Model
APPENDIX A - Classes
Spatial Index Related Features

Class Name: Spatial Index Related Features

Superclass - <Aggregate Feature>

Subclasses

This DRM class is concrete and has no subclasses.

Definition

An instance of this DRM class specifies an aggregation of <Feature Hierarchy> objects in which each component <Feature Hierarchy> represents a different tile within a spatially indexed (tiled) organization of <Primitive Feature> objects within a SEDRIS transmittal. The <Spatial Index Data> link object corresponding to each component A CLASS="Feature_Hierarchy"> Feature Hierarchy indicates which tile it represents.

This DRM class exists to allow <Feature Representation> objects to be organized (tiled) according to some regular spatial index.

Primary Page in DRM Diagram:

Secondary Pages in DRM Diagram:

This class appears on only one page of the DRM class diagram.

Example

  1. See <<Spatial Index Related Organizing Principle>>, example #2.

FAQs

A particular data provider's data consists of a collection of <Areal Feature> instances that are tiled along the lines of a grid, but some <Areal Feature> instances here and there cross over tile boundaries. Can these <Areal Feature> instances be organized with a <Spatial Index Related Features> instance?

Yes, if its strict_organizing_principle is set to SE_FALSE to indicate that the indexing is not strictly followed (see <<Spatial Index Related Organizing Principle>>, example #2). Each tile of the spatial index would be represented by a <Feature Hierarchy> component of the <Spatial Index Related Features> instance.

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)

Inherited Field Elements

SE_Boolean unique_descendants; (notes)
SE_Boolean strict_organizing_principle; (notes)

Field Elements

SE_Boolean sparse; (notes)
SE_Integer_Positive column_count; (notes)
SE_Integer_Positive row_count; (notes)
SE_Long_Float column_width; (notes)
SE_Long_Float row_width; (notes)
SE_Spatial_Index_Spacing_Unit spacing_unit; (notes)

Notes

Associated to Notes


Feature_Representation

 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> instance on the association
 relationship.

Geometry_Hierarchy

 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>
 instance on the association relationship.

Property_Grid

 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> instance on the association relationship.
 Each associated <Property Grid> instance will indicate whether the
 entire <Property Grid> instance or only some specific cell data
 within it is participating in the relationship in question.

Associated from Notes


Feature_Representation

 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> instance on the association
 relationship.

Geometry_Hierarchy

 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>
 instance on the association relationship.

Property_Grid

 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> instance on the association relationship.
 Each associated <Property Grid> instance will indicate whether the
 entire <Property Grid> instance or only some specific cell data
 within it is participating in the relationship in question.

Composed of Notes


Image_Mapping_Function

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

Presentation_Domain

 A <Presentation Domain> component is needed for instances of
 <Aggregate Feature> that are significant only for a particular domain,
 such as radar.

Location

 This is the origin of the collection, which is the lower-left corner.

Fields Notes


unique_descendants

 If the value of the unique_descendants field is SE_TRUE, each
 descendant, that is, each <Feature Representation> instance that
 exists in the component tree rooted at the given <Aggregate Feature>,
 shall be unique, in the
 sense that it shall appear in only one branch of this aggregation.
 If unique_descendants is SE_FALSE, at least one
 <Feature Representation> instance
 appears in more than one branch of the aggregation.

strict_organizing_principle

 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.

sparse

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

column_count

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

row_count

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

column_width

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

row_width

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

spacing_unit

 The spacing_unit field specifies the unit of measurement used
 for the spacing of the spatial index.
Prev: Spatial Index Related Feature Topology. Next: Spatial Index Related Geometry. Up:Index.

Last updated: July 16, 2004 Copyright © 2004 SEDRIS™