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Feature codes are defined and stored in a dictionary of features, attributes and attribute values organized in a standardized coding system
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. Feature codes have not been developed to satisfy the requirements of any single application, product, or data store. Feature codes are intended to
be independent from level of resolution scale, representation, or portrayal. The appropriate selection of features codes and attributes are intended to be implemented as part of the overall
solution for an application, by means of a database supported by a data schema or model, a product, or dataset defined according to a format specification and a data model.
Users of feature codes are advised that, as with any dictionary, there may be more than one way to encode geographic entities, either by offering a choice of features or a combination of features
and attributes. A heliport is listed as feature GB035 Heliport, but could also be encoded as feature code GB006 Airfield associated with the attribute APT Airfield type containing a
coded value of 009 Heliport. Another example would be AK090 Fairgrounds and AK091 Exhibition Grounds, which could be interchanged depending on the users own interpretation.
3.3.8.2 Model Name
When a feature is represented by a 3D model, the model itself is given a name that is used to better describe or differentiate two features having the same feature and FSC codes. Even
though the model name is left to the discretion of the modeler, the CDB standard recommends the use of the feacture code based name as the model name. See the
CDBMetadataFeature_Data_Dictionary.xml for the complete list of feature codes. In the case of Moving Models, the model name is the human-readable version of its DIS Entity Type.
The model name corresponds to the MODL attribute defined in section 5.7.1.3.41.
3.3.8.3 DIS Entity Type
CDB Moving Models make use of the DIS standard see reference [7] to create the directory structures where MModel datasets are stored. The DIS standard uses a structure called the DIS
Entity Type to identify a “moving model”; this structure is made of seven fields named:
1. Kind 2. Domain
3. Country 4. Category
5. Subcategory 6. Specific
7. Extra
The first four fields kind, domain, country and category are used to create four subdirectories in the moving model datasets hierarchy. Each of the directory names is composed of the field’s
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The CDB Feature Data Dictionary FDD is provided with the CDB Standrd in the form of an XML file. An XML Stylesheet is provided to format and display the dictionary inside a standard Web browser. Furthurmore, the
XML Schema defining the format of the FDD can also be found in the Schema subdirectory of the CDB Standard Distribution Package.
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value 1 to 3 digits, followed by an underscore “_”, and concatenated with the field’s name as per Annex M Volume 2 CDB Core: Model and Physical Structure Annexes.
Another directory name is created by concatenating all fields with the underscore character. This character string also forms the Moving Model DIS Code MMDC attribute later defined in
section 5.7.1.3.40.
Together, these five directories classify CDB Moving Models into a DIS-like structure that looks like this:
.\1_Kind\2_Domain\3_Country\4_Category\1_2_3_4_5_6_7\
The above directory structure is used, for instance, by the MModelGeometry dataset later defined in section 3.5.1.
3.3.8.4 Texture Name
