The SEDRIS Data Representation Model
APPENDIX A - Classes
LTSE 3D Location

Class Name: LTSE 3D Location

Superclass - <Location 3D>

Subclasses

This DRM class is concrete and has no subclasses.

Definition

An instance of this DRM class specifies a 3D coordinate for an SRF based on the Local Tangent Space Euclidean SRFT.

See 8.5.6 Local tangent space Euclidean SRFT of ISO/IEC 18026 for a complete definition.

Primary Page in DRM Diagram:

Secondary Pages in DRM Diagram:

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

Example

  1. Consider a <Property Grid> instance that maps wind velocities along a coastline. The <Property Grid> instance uses an SRF derived from the Local Tangent Space Euclidean SRFT with the Y axis parallel to the coast.

  2. An SRF derived from the Local Tangent Plane Space Euclidean SRFT may be used to specify a topocentric coordinate system to model a building.

FAQs

How does the Local Tangent Space Euclidean (LTSE) SRF differ from the Local Space Rectangular (LSR) SRF?

The Local Tangent Euclidean SRF specifies a location in a georeferenced space. The Local Space Rectangular SRF specifies a location in a Cartesian, non-georeferenced "model" space.

If a data provider has a 2D grid, why is the data provider required to specify a height?

Because the Local Tangent Euclidean references a Cartesian coordinate system to a curved surface, the two surfaces are not parallel (in particular, LTSE is not a projection-based SRF). When they are not parallel, a 2D coordinate in one SRF can map to a range of 2D coordinates in the other SRF. Specifying the third coordinate resolves this ambiguity.

If the data provider's grid is small enough or the ambiguity in location is unimportant, the data provider can specify a height as a global parameter of the <Property Grid>. Otherwise, the data provider should specify the height as a separate value in each grid cell, or use several grids of smaller extents.

Constraints

Component of (two-way) (inherited)

Inherited Field Elements

This class has no inherited field elements.

Field Elements

SRM_LTSE_3D_Coordinate coordinate; 1

Notes

Fields Notes

coordinate

The coordinate field specifies the set of coordinate-component values.


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Last updated: July 26, 2006 Copyright © 2006 SEDRIS