Yes, we believe so. The common interpretation of this vision involves the creation of a common and shared library of geospatial services that are created from multiple layers of geographic data that are managed and maintained by different mission agencies. The concept is that these layers are served as geospatial services for use by various applications across organizations and for citizen access.
For example, a state or national government may wish to create a network of distributed servers that manage and serve “framework or essential layers” set up as Web services (i.e. roads, topography, administrative boundaries, land records, and vegetation). Each of these services can be integrated into various applications for the purpose of supporting specific applications that use these layers. This pattern has already been successfully implemented in a number of enterprise systems.
The key issue with this federated architecture involves ensuring that service levels provided by each of the contributing services are maintained consistently and have enough capacity to support the applications. Typically, the agencies who maintain each layer of the infrastructure are only funded for their own mission and not mandated with the responsibility of providing services to other organizations. Therefore, to make a common infrastructure work, agencies need to either be funded to take on the responsibility for serving common infrastructure or, alternatively, the enterprise as a whole needs to be set up as a separate (redundant) application server environment that is shared by everyone.
We believe that over time, GIS users will most likely implement an architecture that combines the mission-focused servers (maintaining each of the framework layers) with a large centralized server that replicates the data and provides centralized application services for the entire enterprise.
In such a hybrid system, the individual thematic layers are maintained in working databases (transaction oriented) with their databases being copied/replicated in a large central system (using ArcGIS replication services). The central system organizes the data into cached data sets for high performance access and support of cross cutting applications. These assured data can also be used in the Web 2.0 environment along with citizen-generated data and mashups.
Enabling technology. ESRI has been working on technology that accommodates exactly this kind of spatial data infrastructure environment, and has been supporting emerging SDI programs around the world.
With ArcGIS 9.3, many of the elements for realizing the SDI vision are now in place. These include:
Beyond technology. Beyond the technology, clearly what is needed to make the concept of SDI work is a governance system that allows full participation across organizations. SDI can be implemented at many different scales (local, state, national, and regional government). It is also beginning to be seen in large global private sector organizations.
Within many governments we see progress. In the US federal government, the FGDC is evolving and becoming more business focused with its geospatial line of business. Similar efforts are occurring in Europe under the auspices of the INSPIRE program and the Canadian GeoConnections program. There are more than 30 active NSDI programs in the world according to the Global Spatial Data Infrastructure Association.
We believe that the SDI vision at all levels of government and private sector companies will eventually become a reality, largely because of the huge benefits of lower costs from data development collaboration and sharing of GIS services. While complex, we believe GIS professionals working together will overcome these issues. ESRI will continue to evolve its technology and support its users and partners around the world in strengthening this vision of multi-organizational collaboration.
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