Ordnance Survey – Great Britain's national mapping agency
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6.5: Web GIS (4)
Web GIS futures
One of the ultimate goals of the GI industry is to have full interoperability between web-based geographic datasets enabling information stored at different locations on the web to be viewed together in single applications (see section 6.2 Standards). With many of the major current GIS products, not only can you access web-based client server versions of the software but the standard desktop software can also load files stored centrally on the Internet. So you could be looking at your locally held map files and then overlay a layer read from a universal resource location (URL) on the WWW. The full vision of interoperability will have web-based applications that can read all data files from any location on the Internet, irrespective of data formats or the software being used.
As well as reading a data layer from a URL it is also possible to submit specific queries (requests) and receive back one or more individual elements. This is known as feature serving. For example, a GIS application could submit a query to a web server requesting information about a district boundaries layer. The response could be a list of the district names held in a particular table. If the client then submits a request for a particular district, the boundary polygon geometry can be returned in response and the individual feature is served to the client application for display, analysis or download. The OGC is very active in establishing standards for map and feature serving on the web – see section 6.2 Standards.
The model by which information is exchanged between systems across the Internet, with small packets of data being returned in response to specific queries, is becoming more pervasive in all areas of computing. Information providers can establish web services in which a single data store is created and standard open programming interfaces are published and made available to system developers.
This means that a system can be developed that can call in exactly the required pieces of information at exactly the time they are needed, rather than having to maintain many multiple copies of the same data, which can soon become out of date and degraded. Fuelled by increased bandwidth, better security and adoption of standards, the Internet has moved from the periphery to become a fundamental component of real-time IT architectures. The world of GIS is no exception to this trend and many GI web services are being developed and made available, replacing the situation of organisations having to obtain large volumes of map data to manage themselves.