Is the EDCS intended to be a tool for the set-up and exchange of real-world geo data, or is it focused on simulation with synthetic data?

Certainly the focus of EDCS is on meeting the needs of the modeling and simulation (M&S) community worldwide. However, there is very little regarding environmental data concepts that are unique to the M&S community. For example the meaning of "synthetic", when used by the M&S community, is "put together" or "integrated". The requirement of the M&S community is to be able to simultaneously and consistently represent information about the world in all environmental domains (e.g., land, sea, air, and space), not in a manner that has been "balkanized" along the lines of traditional disciplines (e.g., land maps vs. ocean charts vs. weather charts).

It is important to remember that much, and perhaps most, environmental data is not measured, but is generated (modeled) by simulations. Very little weather data in your daily weather report is measured at observing stations. But rather, the vast majority of weather data is calculated by complex models and simulations. The same is true for ocean and space data. Terrain data is somewhat unique in that it is much more slowly changing, and historically is thought of as permanent on human-scale time periods. But simulations have a role there as well; for example, the most common representation of the geometry of the surface of the terrain is as a grid of elevation values. But then, what is the "real" elevation spatially between the grid points? Traditionally it is modeled using assumptions about topography as a bilinear interpolation, nearest-neighbor, or spline-fit "approximation". The data we have captured from the "real world" serves merely as boundary conditions for a model that predicts the terrain elevation, everywhere. Is the result "real"? No. Is the result simulation data? Technically, yes, although we all agree to accept the fiction that it is "real".

There is no real distinction between concepts about "the world" used in models and simulations, and concepts about the "the world" used in "the real world". The only difference is the fidelity of the data values associated with those concepts. In many cases, we treat the values of those concepts, when generated by models, as "reality" (as best we can know it) -- for example, the weather or the topography of the terrain. In some cases, yes, models and simulations may be executed (or maps prepared) with totally fictitious data values. That is done every day in the weather community when predictions about future events are generated. It is a common misunderstanding to characterize M&S data as "fake", and all other data as "real". The actual distinctions are much richer and nuanced.

SEDRIS (and EDCS in particular) are used by tools that enable import of products generated by the geo-data community into M&S systems. Import of information from such product datasets is an important element in the creation of M&S databases. But it is also true that M&S databases are already generated, and promulgated, in the "real world" and treated as "real" -- the weather example. SEDRIS technologies, therefore, do not recognize a false distinction between M&S-centric perspectives and non-M&S-centric perspectives. It is intended that there be one set of integrated environmental concepts and, eventually, integrated environmental data characterized by those concepts regardless of the source or destination of the data. The fact that this work springs from the M&S community may be regarded as an accident of history, and should not be regarded as having deeper meaning.

Is the EDCS intended as a replacement for specialized coding catalogues or formats developed by DIGEST, IHO, WMO, ICAO, etc., and is it intended to replace the use of codes from those catalogues in products produced by various sources including national and military mapping agencies?

Specialized coding catalogues or formats have restricted scope, overlap, gaps, and inconsistencies. The EDCS is intended to bring together selected concepts from those specialized catalogues or formats into a common framework so that many communities can both understand each other and use a single set of common concepts that "know no bounds". That set of common concepts can then serve as a basis for meaningful, unambiguous data interchange.

SEDRIS (as a whole) provides mechanisms needed to exchange data sets amongst modeling and simulation (M&S) programs and to import to and export from such M&S systems. But it also provides mechanisms to exchange data sets with "any" application interested in environmental data. While there is no intent to specifically supplant existing data interchange mechanisms where they meet customer requirements (e.g., DIGEST VRF), the SEDRIS technologies intentionally address emerging requirements for an integrated perspective on the environment, and provide an integrated mechanism for representing and exchanging integrated environmental data. Existing mechanisms (specialized catalogues or formats) do not fulfill that requirement. While it happens that M&S systems are the first category of applications to recognize this requirement, we believe that other categories of applications will recognize this emerging requirement in the future, and embrace the SEDRIS technologies where they apply.

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Last updated: May 21, 2002