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The SEDRIS Data Representation Model
APPENDIX A - Classes Data Table Library |
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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>.
A generic seamount could be modeled as a 2-d <Property Grid> of the bottom elevation, surface properties, etc. This grid could be 'instanced' in multiple places in the environment by means of <Property Grid Hook Point> instances to construct a desired situation for training sonar operators.
A table of material properties can be placed in a <Data Table Library> and accessed via <Property Table Reference> instances to identify the materials and their properties for objects in the given transmittal, e.g. the optical or electromagnetic properties in various wavelength bands.
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.
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 a <Data Table Library> if it is not shared by many other objects in the transmittal.
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