The SEDRIS Data Representation Model
APPENDIX A - Classes
Attribute Set Table Group

Class Name: Attribute Set Table Group

Superclass - <SEDRIS Abstract Base>

Subclasses

This DRM class is concrete and has no subclasses.

Definition

An instance of this DRM class specifies an interchangeable group of one or more <Attribute Set Table> instances. The primary <Attribute Set Table> in the group is indicated by the primary_table_index. When a reference is made to an <Attribute Set Table> (for example, from an <Attribute Set Index> component of a <Polygon>), the reference identifies the <Attribute Set Table Group> and the index within the <Attribute Set Table>, but not the specific <Attribute Set Table> within the <Attribute Set Table Group>. By definition, an <Attribute Set Index> refers to an <Attribute Set> from the primary <Attribute Set Table> of the indicated <Attribute Set Table Group>. An alternate <Attribute Set Table> from within the < Attribute Set Table Group> can be chosen at the discretion of the data consumer.

Primary Page in DRM Diagram:

Secondary Pages in DRM Diagram:

Example

  1. One <Attribute Set Table Group> in the transmittal, and that group has only one <Attribute Set Table> within the group. That <Attribute Set Table> is the one and only <Attribute Set Table> for the entire transmittal.

  2. An <Attribute Set Table Group> with two <Attribute Set Tables>. One <Attribute Set Table> for normal, Out The Window (OTW) viewing, and another <Attribute Set Table> to change the appearance of the view to be a view as seen through Night Vision Goggles (NVG).

  3. An <Attribute Set Table Group> with 3 <Attribute Set Tables> with the same usage of OTW. Why 3 tables? One <Attribute Set Table> defines the colours and textures as originally created by the data modelers. The second <Attribute Set Table> has different shades of blue for the lakes and skies because a company VIP came through and didn't like the blues that were there. The third <Attribute Set Table> contains yet another set of blues for the lakes, different textures for the lakes and different shades of green for the trees and tanks, because the customer in charge of the program came through and didn't think the colours and textures were realistic.

FAQs

Can a transmittal in any way refer to an <Attribute Set Table> in an <Attribute Set Table Group> other than the primary <Attribute Set Table>?
No. The only <Attribute Set Table> that can be referenced in any <Attribute Set Table Group> is the primary <Attribute Set Table>.

Since they cannot be referenced in a transmittal, why bother to have alternate <Attribute Set Tables> within an <Attribute Set Table Group>?
Because in real life, many run-time systems have multiple colour and material tables they can switch between for various reasons, and these tables should be shared to promote interoperability. See the example section, below.

Constraints

Associated by (one-way)

Composed of (two-way)

Composed of (two-way metadata)

Component of (two-way)

Inherited Field Elements

This class has no inherited field elements.

Field Elements

SE_Integer_Positive primary_table_index; (notes)
SE_Integer_Positive table_size; (notes)

Notes

Fields Notes


primary_table_index

 index of the primary <Attribute Set Table> component
 (from the ordered list of <Attribute Set Table>
 components in this <Attribute Set Table Group>)

table_size

 the size of any and all <Attribute Set Tables>
 within this <Attribute Set Table Group>

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Last updated: October 1, 2002 Copyright © 2002 SEDRIS™