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Requirement 25
http:opengis.netspecCDB1.0cor ebase-material-order
The base materials that make each substrate SHALL be listed in decreasing order of weighting.
Requirement 26
http:opengis.netspecCDB1.0cor ecomposite-material-tag
Each composite material SHALL be tagged with a non-negative integer index, zero being reserved for default value that is assigned by the CDB data manipulation tools.
In addition, each composite material can be optionally tagged with a descriptive name. The CDB composite material table mechanism provides the means to tag each CDB composite
material with a data store tool-specific or modeler-specific composite material name.
2.5.2.3 Example 1
Consider a linear feature in a CDB data store that corresponds to a painted stripe on a runway surface. The linear feature is stored in the Man-Made Lineal dataset; the linear feature
references an entry into the Geocell’s Composite Material Table. That reference is the index of the Composite Material for painted asphalt. The entry pointed to describes a Composite Material
whose Primary Substrate is 100 BM_ASPHALT and whose Surface Substrate is 100 BM_PAINT-ASPHALT.
2.5.2.4 Example 2
Consider a terrain polygon feature in the GSFeature dataset. The polygon feature covers a large wetland area that contains 4 Base Materials, namely BM_SOIL 21, BM_WATER-FRESH
51, BM_LAND-LOW_MEADOW 26 and BM_SAND 2. The polygon feature references an entry into the Geocell’s Composite Material Table. That reference is the name of
the Composite Material for wetlands. The entry describes a Composite Material whose Primary Substrate is composed of four Base Materials, namely water with 51 weight, low height
vegetation with 26 weight, soil with 21 weight and sand with 2 weight.
2.5.3 Bringing it all Together
Figure 2-9: Flow of Material Attribution Data illustrates the flow of material attribution data from features in the CDB right through to the client-device.
Each of the raster features in a CDB structured data store can and should reference a Composite Material. The reference points to an entry into a Composite Material Table. Each CDB tile has a
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Composite Material Table. The impact of additions, deletions, and modifications to the Composite Material Table are limited to only those features that make up the tile; this reduces
the compilation time associated with the production of Composite Material Table data.
Likewise, zones and polygons within a 3d model, such as OpenFlight, can optionally reference one or more Composite Materials. The references each point to entries into a Composite
Material Table that is associated with the model. Each model can have an associated Composite Material Table. The impact of additions, deletions, and modifications to the Composite Material
Table are limited to only those features that make up the model; this reduces the generation time associated with the production of Composite Material Table data for the model.
In turn, each of the entries in the Material Composite Table has one or more references to Base Materials entries of the Base Materials Table. The Base Materials Table is global to the CDB
and its contents are defined and governed by this Standard.
Figure 2- 9: Flow of Material Attribution Data
2.5.4 Determination of Material Properties by Sensor Environmental Model SEM
Please refer to implementation guidance in Volume 10 OGC CDB Implementation Guidance, Sections 6.4.7.1 and 6.4.7.2.
key3 key18
key21 key13
key7 key36
key28 key24
key31
key4
α ε γ
material0 material1
material2 material3
material4 material5
material6 material7
material8 material9
material10 material11
material12 material13
material14 material15
material16 material17
material18 material19
Dataset Composite
Material Table
CDB’s Base Material
Table SEM Base
Material Table
τ µ
Feature locally references a
Composite Material
Local to CDB Tile Global to CDB
Local to the Client-device SEM
P
1
S
1
S
2
S
1 CMIX
P
2
P
3
Surface substrate Primary substrate
Secondary substrate
Secondary substrate
Composite Materials each reference one or more global Base Materials
CDB’s Base Materials each reference SEM Base Materials and hence SEM
material properties
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Requirement 27
http:opengis.netspecCDB1.0cor esem-base-material
The specialist SHALL ensure that his SEM has a corresponding Base Material for each of the CDB Base Materials.
2.5.5 Generation of Materials for Inclusion in CDB Datasets
