The SEDRIS Data Representation Model
APPENDIX A - Classes
Spatial Resolution LOD Data

Class Name: Spatial Resolution LOD Data

Superclass - <Base LOD Data>

Subclasses

This DRM class is concrete and has no subclasses.

Definition

An instance of this DRM class specifies the spatial resolution of the associated data, which governs the switching of objects by a spatial resolution based <LOD Related Geometry> instance or <LOD Related Features> instance.

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 transmittal containing data imported from DTED. DTED is produced at a number of standard spatial resolutions such as 30 arc seconds, 3 arc seconds, 1 arc second, and 0.3 arc second. A <Spatial Resolution LOD Data> link object specifies the spatial resolution of the data contained in the associated DRM object.

  2. Sets of atmospheric environmental data are often produced in an SRF based on a map projection augmented SRFT (such as LCC_Augmented_3D) at a number of standard spatial resolutions such as 81 kilometres, 27 kilometres, and 9 kilometres. A <Spatial Resolution LOD Data> link object specifies the spatial resolution of the data contained in the associated DRM object.

FAQs

Why not just use <Map Scale LOD Data>?

The <Map Scale LOD Data> class can be used in some cases as a rough approximation. However, many data sets require more precision.

For example, while <Map Scale LOD Data> can be reasonably applied to lower-resolutions of DTED (e.g., levels 0, 1, and 2), it does not apply well to higher resolutions of DTED, and it does not apply at all to bathymetric and atmospheric data.

If the spatial resolution is different among two or more spatial axes, which is to be used?

In this case, normally the highest resolution is to be used.

Constraints

Component of (two-way) (inherited)

Inherited Field Elements

This class has no inherited field elements.

Field Elements

SE_Long_Float spatial_resolution; 1
SE_Spatial_Index_Spacing_Unit unit; 2

Notes

Fields Notes

spatial_resolution

The spatial_resolution field specifies the spatial resolution of the associated data and shall be a positive value.

unit

The unit field specifies how the spatial resolution value is measured.


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Last updated: July 26, 2006 Copyright © 2006 SEDRIS