The SEDRIS Data Representation Model
APPENDIX A - Classes
Data Table Library
|
|---|
Class Name: Data Table Library
Subclasses
This DRM class is concrete and has no subclasses.
Definition
An instance of this DRM class is a <Library> containing
<Data Table> instances that can be referenced
or 'instanced' by an object within the transmittal. If the particular
<Data Table> is a <Property
Grid>, the associating <Geometry> shall have a
<Location> that is used as the origin for the
spatial <Axes> in the <Property
Grid> - most often a <Property
Grid Hook Point>. A (non-spatial) <Property
Table> is assumed to provide information that applies
to the entire associating <Geometry> or
<Feature>. A
<Property Table Reference>
may be employed to select a (N-1)-dimensional slice from the
referenced <Data Table> in the
<Library>.
Primary Page in DRM Diagram:
Secondary Pages in DRM Diagram:
Example
A generic seamount could be modeled as a 2-d
<Property Grid>
of the bottom elevation, surface properties, etc. This grid could
be 'instanced' multiple places in the environment by means of
<Property Grid Hook Points>
to construct a desired situation for
training sonar operators.
A table of material properties can be placed in the
<Data Table Library> and accessed via
<Property Table References> to
identify the materials
and their properties for objects in the given transmittal, e.g. the
optical or electromagnetic properties in various wavelength bands.
FAQs
- Why place a <Data Table> in a
<Library> rather than directly under an
<Environment Root>?
- Most often so that it can be reused easily ('instanced' or referenced)
from multiple places in the transmittal. This sharing can be especially
important for tables such as material properties that do not 'belong'
to any one object in the normal sense. An additional reason may be to
make the <Data Table Library> the
progenitor of the <Data Table>, i.e., to make the
<Data Table Library> the master manager of
the memory allocation for the table.
- When should a table not be placed in a
<Data Table Library>?
- There are no situations that are prohibited by SEDRIS data
representation model or constraints. However, there is little benefit
from placing a <Data Table> in the
<Data Table Library> if it is not shared
by many other objects in the transmittal.
Constraints
None.
Composed of (two-way)
Composed of (two-way metadata)(inherited)
Component of (two-way)
Inherited Field Elements
This class has no inherited field elements.
Prev: Data Table.
Next: Description.
Up:Index.
|
Last updated: October 1, 2002
|
Copyright © 2002 SEDRIS™
|
|