Technology
A Technology Architecture to Support an Indian National Geospatial Data Infrastructure
Dr David J. Maguire
Director Products, Solutions and International, ESRI
Email : dmaguire@esri.com
The development of GIS databases over the last decade has led to a collection of powerful islands of data within a nation state. Each scientific discipline often contains tens or hundreds of diverse datasets, at national and local level institutions. These unconnected GIS databases have a wealth of information collected at different scales and projections and with different database schemas, and may in many cases represent the same topic of study or interest. Regardless of the source or size, they all reflect a national investment, in software, hardware training and expertise, which needs to be managed in such a way to make the most use of past and future investments for the future development of a country.
At the national level, development decisions are becoming increasing dependant on understanding a host of diverse but interconnected issues such as environmental, urban, agriculture and other stresses and development issues. While the use of GIS in national policy making has been used increasing in the U.S. over the last 5 years, we are now seeing an acceleration of the emergence of national GIS efforts internationally. Increasingly, national governments are accepting spatial databases as an important component of their national information infrastructure, for they assist in the understanding of the complex systems they must understand in order to progress national development. The benefit to the GIS community of national recognition elevates the science to a whole new level of importance, which will have profound implications in many areas.
As more countries begin to see the advantage of using geographic information they are investing wisely in infrastructure to stimulate business development and support rising demand. Geographic information and geographic analysis can be used in many strategic, tactical and operational activities, including facility location, regional planning, land management, asset inventory, sustainable development, routing and scheduling, emergency response and many more.
The key requirements of a national geographic data infrastructure include
- Low cost
- Ease of use
- Support for distributed users
- Use of commercial off-the-shelf technology
- Availability of key data layers
- Ability to integrate with existing technologies and programs
- Standard data access
- Support for extensibility to adapt to new areas and changing circumstances
- Centralised directory or clearinghouse of metadata information
The start of a new millennium coincides with a breakthrough in technology that dramatically reduces the cost of building and maintaining a NGDI. The evolution of Internet technologies and service-based GIS architectures makes it feasible to build a NGDI using COTS software that meets the requirements outlined above. Indeed, such is the pervasiveness of the Internet that National GDI can link together to forma a Global GDI.
One model for a NGDI is that used in the Geography Network (www.GeographyNetwork.com). The Geography Network is a collaborative, and multi-participant system, for publishing, sharing and using digital geographic information on the Internet. The Geography Network can be thought of as a large online library of distributed GIS information, available to everyone. It has been designed to adhere to open standards for the dissemination and sharing of data and services. The Geography Network is a global network of geographic information users and providers. It uses the Internet to connect distributed users over standard telecommunication links. Geographic data and processing are available in real time via the Geography Network. Client applications can be simple web-based applets and/or sophisticated high-end GIS. The Geography Network is a fully distributed collection of servers that publish data and processing services. Information about these services can be discovered by consulting the on-line catalog. The services provide data and processing in direct use mode – that is they can be consumed in near real time by standard GIS applications. Desktop GIS users, for example, can supplement local data and processing capabilities with remote data accessed over the Internet. For lightweight clients, for example, Pocket PCs and modest Internet browsers the Geography Network offers access to very powerful and sophisticated processing capabilities, such as buffering, overlay analysis, routing and high quality mapping. Just the results of such activities can be downloaded to the client for viewing and further analysis.
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