BACKGROUND
Environmental data is an integral part of many of today’s information technology applications. The use of environmental data will grow substantially as availability and access to such data increases and as tools for manipulation of environmental data become less expensive and more sophisticated.
As this trend continues, the representation and sharing of environmental data will play a key role in the interoperation of heterogeneous systems and applications that use such data. This need was recognized in the mid-80’s, when the ability to network large numbers of heterogeneous simulation systems became a practical reality. Research and work in this area continued while a better and more complete understanding of the complex issues associated with describing and sharing of environmental data for a wide variety of (simulation) applications was formed. SEDRIS was conceived in order to tackle these issues in a uniform and unified manner.
Although the initial application domain for SEDRIS stems from the needs of the modeling and simulation field, it was immediately recognized that the representational technologies required to capture and communicate environmental data are fundamentally one and the same, and, in large part, can be dealt with independent of the end-applications.
At the same time, it was also understood that too often end-applications shape and form the characteristics of how data and data representation are used. The challenge for SEDRIS, then, was to provide a means for representation and sharing of environmental data which not only was efficient in practical use, but also was specific enough to address the real needs of a wide variety of end-applications, while preserving the degree of semantics needed for others to understand the nature of the data. The range of end-applications included representation of environmental data for such things as analysis, visualization, simulation, planning, modeling, etc. This took into account the meteorological and oceanographic communities, the simulation sector (both military and commercial), the GIS (or more broadly the environmental information systems) community, the military operational community (i.e. C4I), as well as others who needed to share or communicate environmental data.
Added to this was the goal of getting away from stove-pipe views of the environment, and providing a mechanism that also allowed for integrated environmental data to be represented. Integrated environmental data, where ocean, terrain, atmosphere, and space data (about a region) can be seamlessly represented, was recognized as a key component of many future information technology applications. And although very few applications today deal with such diverse data at the same time, developers of SEDRIS believed such a need will be reality in the future.
With these objectives and challenges in mind, SEDRIS was initiated in 1994. SEDRIS has been conducted as an open project with the objective of solving these challenges in practical ways that can be immediately used by both data providers and consumers, while at the same time leveraging and taking advantage of existing standards whenever possible.
SEDRIS is about …
As its name implies, SEDRIS is fundamentally about two key aspects: (1) representation of environmental data, and (2) the interchange of environmental data sets.
To achieve the first one, SEDRIS offers a data representation model, augmented with its environmental data coding specification and spatial reference model, so that one can articulate one's environmental data clearly, while also using the same representation model to understand others' data unambiguously. Therefore, the data representation aspect of SEDRIS is about capturing and communicating meaning and semantics.
For the second part, we know from practice that it is not enough to be able to clearly represent or describe the data, we must also be able to share such data with others in an efficient manner. So the second aspect of SEDRIS is about interchange of data that can be described using the data representation model. For the interchange part, the SEDRIS API, its format, and all the associated tools and utilities play the primary role, while being semantically-coupled to the data representation model.
In this regard, SEDRIS does not try to judge, side with, separate, or distinguish how various domains use environmental data. Instead it provides a unifying mechanism for all of them to describe (and subsequently share) such data, without detracting from one or the other.
For example, (and to play a variation on an old phrase) a road is a road! Whether it is viewed as a linear feature in one domain, or as a series of polygonal facets in another does not (and should not) change the fact that the representation is about the same "thing". Similarly, a cloud is a cloud, whether it is represented as a collection of moisture content point samples within a geographically large 3D grid, or within a weather map whose features are identified as "fronts" and low- or high-pressure regions.
These are just different descriptions of the same thing, but viewed from different application perspectives. The challenge is to capture and unify all these differing "views" of environmental data. SEDRIS does this by providing an architecture that allows these varying representations to coexist in a consistent and coherent manner. It provides connections (associations) between the different representations, while allowing the appropriate attributions to be expressed for each representation.
As a result, SEDRIS is not just about a particular application sector's use of environmental data (e.g. simulation or visualization). If there is a schema that represents the relationships, semantics, and attribution of the data elements very well (which we think SEDRIS does), then almost any domain can articulate its environmental data without imposing on, or impeding, the others' "views".
Because of these characteristics, the representational aspect of SEDRIS is much like a language or a method for unambiguously describing the environment, independent of whether the environment is geo-specific, geo-typical, or completely fictitious. And the interchange aspect is a mechanism for sharing the described environmental data.
Put together, SEDRIS is simply an infrastructure technology. It provides the enabling foundation for IT applications to express, understand, share, and reuse environmental data.
SEDRIS is not …
Since sometimes the line between an infrastructure technology and the applications that use it can be blurred, it helps to enumerate what SEDRIS is not.
Because SEDRIS is often used in the database conversion process, sometimes people think it is an application that converts databases. Some have thought SEDRIS is an authoring tool, used to build environmental data sets. Others have assumed SEDRIS is really a single environmental database that can cater to many needs, or that it is an archiving, repository, or a discovery mechanism for environmental data.
SEDRIS is none of these, but as an enabling technology it does, and continues to, play a significant role in each of these areas. As an interchange mechanism, SEDRIS is at the crossroads of many diverse IT applications that require environmental data. And its powerful representational concepts and schema have already influenced many authoring, database generation, and IT applications. So it’s easy to see how it can be confused with some of the applications that it serves.
But the fundamental aspects of SEDRIS remain the unambiguous representation of environmental data and the efficient interchange of such data through its software technologies.
SEDRIS OBJECTIVES
Since its start SEDRIS has maintained several fundamental objectives. The most notable of these are: (a) to provide a powerful methodology for articulating and capturing the complete set of data elements, and the associated relationships, needed to fully represent environmental data; (b) to provide a standard interchange mechanism to distribute environmental data and to promote database reuse among heterogeneous systems; and (c) support the full range of applications across all environmental domains that span ocean, terrain, atmosphere, and space.