The importance of metadata engines in spatial data infrastructures

With the rapid increase in the development of spatial data collection tools, such as GPS and remote sensing technologies, the amount of spatial data being collected and stored on computer networks is becoming vast. Knowing what spatial data is already available for an area is of great benefit to many spatial data users as duplication of spatial data collection and processing is a time consuming and costly exercise. Descriptive data about the data sets are maintained as metadata to provide such information to spatial data users. Current Spatial Data Infrastructure (SDI) technology allows search engines to search metadata systems within a network to discover what spatial data is in existence. As SDIs evolve, it is expected that spatial data sets will be accessed "live" from their distributed locations, rather than being downloaded before being used. With this development, it is anticipated that metadata systems will evolve into metadata engines and will again be background tools that are used for querying spatial data sets that are distributed across a network. This paper will describe the terms metadata and metadata engines in relation to SDIs. The paper will also discuss the trend towards distributed processing of spatial data and the evolving SDIs. Details will be given about the processes and problems of developing a prototype, using a public-domain package, ISITE, as a starting point, that will allow for simple distributed processing of spatial data to occur. The Importance of Metadata Engines in Spatial Data Infrastructures