In order to support the unambiguous description of environmental data, SEDRIS specifies:

• a Data Representation Model (DRM)
• a Spatial Reference Model (SRM), and
• an Environmental Data Coding Specification (EDCS).

While the DRM addresses how to describe "environmental things" in terms of data modeling constructs meaningful to simulation developers (e.g., geometry, feature, image, topology, and data table), it explicitly avoids specifying "where" the "environmental things" are, and enumerating all of the "environmental things" that these data modeling constructs could be used to represent.

The SRM captures and unifies the spatial models used by SEDRIS, plus the many others that are not currently used but can be easily added. These models include inertial, quasi-inertial, geo-based, and non-geo-based (purely arbitrary Cartesian) systems. The SRM provides a unifying mechanism for specification and inclusion of any spatial reference frame and coordinate system. Its algorithms are designed to retain a high degree of accuracy during transformation and conversion operations (1mm accuracy).

The EDCS provides a mechanism to specify the environmental "things" that a particular data model construct is intended to represent. That is, a "tree" could be represented alternatively as a <Point Feature>, an <Aggregate Geometry>, a <Data Table>, a <Model>, or some combination of these or other DRM constructs. Which of these the data modeler (i.e., the data provider of a SEDRIS transmittal) chooses is orthogonal to the semantic of the "thing" that is represented (and its location). The provision of such a "thing" in a SEDRIS transmittal must result in a shared understanding of "what the thing is and what it potentially means" to all applications consuming that transmittal.

For more detailed information on the EDCS, visit the following pages:

• EDCS Background
  • EDCS Purpose
  • EDCS Overview
  • EDCS Structure
  
  

The following links provide additional information on the content and implementation of EDCS 4.1:

• Dictionaries:

  • EDCS Classification Dictionary
  • EDCS Attribute and Enumerant Dictionaries
  • EDCS Attribute Value Characteristic Dictionary
  • EDCS Unit, Scale, and Unit Equivalence Class Dictionaries
  • EDCS Organization Schema and Group Dictionaries

• Function and Type Definitions:

  • EDCS Functions
  • EDCS Type Definitions

Concepts may be mapped from other environmental data coding systems to the EDCS Version 4.1, and vice versa. Several such mappings have been completed, and more are currently in development. Each consists of both a set of data files which declaratively specify how concepts from another environmental data coding system are individually expressed using concepts in the EDCS Version 4.1, and an associated functional API which allows application developers to integrate a standard implementation of those concept-to-concept mappings into their application.

The following subsections provide additional information on these environmental concept mappings.

Documentation for this mapping, and the associated API implementation, will be made available as a separate package from www.sedris.org. The following hyperlinks will not work unless you have installed the mapping API SDK.

• FACC 2.1 to EDCS 4.1 Mapping Main Page
• FACC 2.1 to EDCS 4.1 Mapping API
• FACC 2.1 to EDCS 4.1 Release Notes

Documentation for this mapping, and the associated API implementation, will be made available as a separate package from www.sedris.org. The following hyperlinks will not work unless you have installed the mapping API SDK.

• EDCS 4.1 to FACC 2.1 Mapping Main Page
• EDCS 4.1 to FACC 2.1 Mapping API
• EDCS 4.1 to FACC 2.1 Release Notes