ABSTRACT
The concepts and development of the Spatial Data Infrastructures (SDIs) have been in continuous evolution since the middle 1990s. The establishment of SDIs was driven by: a) the spatial data itself, characterized by high generation costs, duplication, digital availability, inconsistency and increasing volume; b) the expanding Internet capabilities and capacity; and c) the need to easily access and use the spatial data and information for knowledge-based decision making at various levels of government. While the same reasons are still valid today, there are additional factors that motivate the further development and implementation of SDIs. These include the “democratization” of geo-spatial information by both users and traditionally non-geo-spatial technologies, the development of new geo-spatial-enabled technologies and applications, the need of geo-spatial related services, the evolution of geomatics science, data acquisition
technologies and systems, the wide use of the Internet and the World Wide Web (WWW), the computer, information and communications technologies, the regionalization and globalization of geo-related issues, and the budgetary pressures on the traditional geo-spatial data providers (e.g. national mapping organizations) for cost-benefit review of their operations. These recent developments are changing the traditional role of SDIs, from an Internet-based virtual warehouse (repository) for access, visualization and delivery of geo-spatial data to a virtual geo-spatial serviceoriented user driven enterprise (Fig. 24.1), delivering not only data but services, applications and solutions in support of data providers, service providers and application developers using interoperable and reusable components (CGDI 2004).
