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Part III. Appendix 2: Data Transportdate, OGC has developed three Web Mapping Service specifications: OpenGIS Web Map ServerSpecification (Approved), OpenGIS Web Feature Server Specification (Candidate), and an Open-GIS Web Coverage Server Specification (Candidate).[Note added by the Data Transport Team: The Web Map Server delivers pictures over the Web; it isnot a data server. The specifications for the feature and coverage servers which are the OGIS dataservers have not been finalized; at present, only candidate specifications exist.]OpenGIS Geospatial Fusion Services: Non-map information—text, video, audio, digital photographs,mpeg movies, sensor data, word processing documents, etc.—often refers to place. It wouldbe useful for many people in many situations to be able to “fuse” information such as addresses,place names, coordinates, pinpoints on photographs, and descriptive directions into one informationmanagement framework that would support search, discovery, and sharing of spatial informationstored in non-map formats. This is the goal of OGC’s “Geospatial Fusion Services (GFS),”which currently include: OpenGIS Gazetteer Service Interface (GAZ) Specification (Candidate),OpenGIS Geocoder Service Geocoder (GeoC) (Specification (Candidate), OpenGIS GeoParserService (Geoparser, or GeoP) Specification (Candidate), and OpenGIS Location Organizer Folder(LOF) Specification (Candidate).DATA EXCHANGE INFRASTRUCTURE (DEI) AND THEFIELD SPATIAL DATA MODEL (FSDM)DEI began as a project within the Naval Research Laboratory. Physitron (Huntsville, AL), which isalso a member of OpenGIS, accomplished much of the design work and helped develop the Open-GIS standards to which DEI adheres. To provide standardized data representation, DEI adopted theEnvironmental Protection Agency’s Field Spatial Data Model (FSDM) developed by Todd Plessel.Largely due to fluctuations in funding support, DEI and the FSDM are in regular use only at theNational Coastal Data Development Center (NCDDC), where a C++/Java implementation is themiddleware for transporting data.DEI is a set of CORBA-based interfaces used to locate and transfer geospatial data. It is a client/server architecture in which the server, or gateway, is responsible for (1) translating a request fordata into a data source’s access method to acquire the data and (2) putting the resulting data intoa representation that is then ingested into the FSDM. That representation is called the Field DataMarkup Language (FDML) Streamer, which is transported (via CORBA’s IIOP transport protocol)to the client, which translates it into FSDM internal objects. Note that the data, unless they are relativelysmall, are not transported at this time. The data are transported from the gateway as neededby the client.176