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Together, these files provide all the information required to build the names of all directories permitted by the standard.
1.5 CDB Feature Data Dictionary
The CDB Feature Data Dictionary FDD is provided with the CDB standard in the form of an XML file. An XML Stylesheet is provided to format and display the dictionary inside a standard
Web browser. Furthermore, the XML Schema defining the format of the FDD can also be found in the Schema subdirectory of the CDB Schema Distribution Package.
See CDBMetadataFeature_Data_Dictionary.xml for the complete list of the supported codes
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. Please see section
3.3.8.1 for more detailed information on the use of feature codes and
extensions to that codelist in the CDB standard.
1.6 Introduction
1.6.1 Purpose
This standard provides a full description of a data model aka schema for the synthetic representation of the world. The representation of the synthetic environment in the CDB model
as expressed in a physical data store is intended for use by authoring tools and by various simulator client-devices that are able to simultaneously retrieve, in real-time, relevant
information to perform their respective runtime simulation tasks. With the addition of the DIS protocol, the application of the CDB standard provides a Common Environment to which inter-
connected simulators share a common view of the simulated environment.
1.6.2 Document Structure
This document is structured as follows. Section 1.6 defines general CDB data store and implementation requirements
Sections 2.1, 2.2, 2.3, and 2.4 provide an overview if key elements of the CDB data store structure.
Section 2.5: CDB concepts and semantics. Describes the naming and handling of materials that make up the synthetic environment
Section 3.0: Focuses on aspects of the data model that relate to the structure of the data store repository on the storage subsystem. The organization of the CDB data into tiles, levels-of-detail
and datasets is embodied through a set of conventions that prescribe the CDB directory hierarchy and file naming conventions.
Section 4: CDB File Formats provides a description of all the formats prescribed by the CDB Specification.
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Currenrly, these are FACC codes, Future revisions of the CDB standard shall provide guidance on using other feature code lists.
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Section 5: CDB Datasets provides a detailed description of all CDB datasets. The current CDB standard relies on established industry formats:
• The TIFF format. TIFF encoding rules are defined in Volume 10: OGC CDB
Implementation Guidance; •
The Best Practice use of the OpenFlight
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format Volume 6: OGC CDB Rules for Encoding Data using OpenFlight;
• The RGB format. Included in the Gamma Tutorial Section, Volume 10: OGC CDB
Implementation Guidance •
The Best Practice use of the Shapefile format in a CDB data store. The Shapefile table content encoding rules are in Volume 4. Volume 4: OGC CDB Best Practice use of
Shapefiles for Vector Data Storage; •
JPEG 2000 file format Volume 2: OGC CDB Core Model and Physical Structure Annexes, Annex H.
Each of these documents has been annotated to reflect the conventions established by the CDB standard. The Best Practice conventions currently define how TIFF, OpenFlight, RGB,
Shapefile and JPEG 2000 formatted files are to be interpreted by CDB-compliant simulator readers. Additional encoding formats and conventions will be defined for future versions of the
CDB standard.
Annexes J and F of Volume 2 provide the CDB light type naming hierarchy and the CDB model component hierarchies respectively while \CDB\Metadata\Materials.xml provides the material
list for the CDB standard.
Other Annexes in Volume 2 further describe additional aspects of the CDB standard: •
Providing the CDB Directory Naming and Structure Annex M, •
List of Texture Component Selectors Annex O see footnote 32
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, •
SGI Image File Format http:paulbourke.netdataformatssgirgbsgiversion.html, •
Table of Dataset Codes Annex Q
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• How some datasets are derived from others Annex R see footnote 32.
1.6.3 What is the CDB Standard: An Overview
