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The SEDRIS Data Representation Model
APPENDIX A - Classes Spatial Resolution LOD Data |
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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.
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.
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.
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.
In this case, normally the highest resolution is to be used.
| SE_Long_Float | spatial_resolution; | 1 |
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| SE_Spatial_Index_Spacing_Unit | unit; | 2 |
The spatial_resolution field specifies the spatial resolution of the associated data and shall be a positive value.
The unit field specifies how the spatial resolution value is measured.
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