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Geographic Information Infrastructure
Applications | Technology | Right to Information Evolution of Systems for a National Spatial Data Infrastructure
Preetha Pulusani Intergraph Mapping & GIS Solutions Huntsville, Alabama U.S.A Email : prpulusa@india.ingr.com The occurrence of a national emergency, resulting from a cyclone, flood, tsunami, major fire, or even the recent Gujarat earthquake is unfortunate. However, it is apparent that some damage from these sorts of events can be avoided and fewer people are likely to die, if a plan is quickly developed and implemented to address the catastrophe. Subsequent decision/support efforts when lives are at risk and seconds count, are aided by fast communications and the availability of accurate and up-to-date spatial and situational information. For example, it is now possible for all participants in rescue/recovery operations to know their location at all times through the use of satellite positioning. With modern communications technology, it is possible for the same location information to be readily available to all agencies coordinating and managing specific aspects of recovery efforts. The addition of current geospatial information, possibly including georeferenced, high-resolution digital imagery products, makes the local situation meaningful to the command-and-control center decision makers, who are commonly physically separated from the field operations. It is apparent that geospatial data constitutes much of the information required for physical disaster planning, management and recovery work. Given that natural and man-caused disasters will continue to occur, a major issue is the ability of various users to share and access necessary information. Previously, digital geographic information was shared by sending large data files that had to be converted or translated if the data-sharing partners didn’t have the same software brand. Now interfaces, based on OpenGIS Specifications created by the Open GIS Consortium, allow Internet data servers to be queried remotely by other vendors’ clients, and subsequently extract only the query-specific information from those large data files. Vendors no longer need to worry about standardizing data formats or updating data conversion routines when other vendors change formats. Users do not need to be held captive to proprietary formats and proprietary GIS systems because data servers can access and manipulate data in its native format. Legacy data no longer requires migration, translation, and conversion. The power of open architecture allows the user to bypass these functions. Sophisticated n-tier architecture allows organizations to provide a variety of data and access to groups across the enterprise, via an intranet, or the Internet. The result is live connections to real-time information - the heartbeat of any successful enterprise. Clearly, it is time to stop thinking about platform, data format, and data type compatibility and instead to think about how to integrate legacy data with geoprocessing and geoengineering software to solve problems in specific applications. Effective geospatial data sharing requires OpenGIS-conformant interfaces, but also requires coordination in naming and describing geographic features as well as consistent structuring of geographic metadata. For example, in the United States, the Federal Geographic Data Committee (FGDC) has been established as the center of federal coordination and standardization efforts, and the National Spatial Data Council (NSDC) is chartered to anchor national efforts. Through maturing of Open Systems and coordination of local, regional and national spatial data infrastructures, the Internet and intranets will be populated with thousands of interoperable geodata sources. Soon, information concerning a particular region or theme will be indexed by spatial catalogs in a manner similar to the way text information is indexed by World Wide Web search engines. Little expertise will be required to quickly gather and overlay spatial data from diverse sources and merge them into the multi-agency, multi-contractor work flows that increasingly typify public - and private - sector projects. Internet commerce schemes, in which servers dispense data to users at rupees per access or kilobyte, will figure prominently in the GIS market as well as in the business models of government agencies. Thus, it can be seen that the combined efforts of vendors of GIS, desktop mapping, automated mapping/facilities management, Earth imaging, and data bases are causing significant progress towards interoperability. Interoperability refers to the ability for software components to integrate even when modules are written by different software organizations or vendors. Over the past decade, several technologies have emerged which provide the infrastructure to enable interoperability; the Component Object Model (COM), the Common Object Request Broker Architecture (CORBA) and Java technology are the most notable. Each of these technologies provides a certain degree of interoperability on its own, however, the goal of complete interoperability across platforms remains elusive. Recently, Extensible Markup Language (XML) has emerged as the standard for the exchange of data between heterogeneous systems, primarily because of its simplicity, which allows users to design ways of describing information, usually for storage, transmission or processing by a program. As a text-based system to encode data, it is completely platform independent. Whenever an application receives an XML file, it also gets descriptions about how the data is structured. That way, a program can more easily determine how to process the data. This characteristic makes it especially suitable for use in the World Wide Web, where cooperation is required between large arrays of dissimilar software components.
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