Ordnance Survey: Putting GIS on the map
Published: 23 Oct 2003 17:30 BST
The live map can also be accessed by companies who want to build or implement their own geographical information systems. Significant features such as houses usually appear on the map within six months, says Neil Wilkins. A lot of work is done by the surveyors on the ground, and depends on building relationships with local authorities and the Land Registry. "We think we get about 80 percent of the information from these sources," says Wilkins.
The result is that everything larger than eight square metres ends up on the map, and lots more that is smaller. Measurements are accurate to the centimetre, claims Wilkins.
Ordnance Survey's MasterMap is also about more than just lines. When computerisation of the records began, OS maps were nothing but lines -- walls, ditches, hedgerows -- dividing spaces. Today the Master Map is all about what fills those spaces, and as a result is believed to be one of the largest Oracle spatial databases in the country, occupying a terabyte of storage space.
Information in this database includes everything from forests, roads and houses to garden plots and even pillar boxes and post codes. It is the post code data that lets the ZDNet UK/OS Wi-Fi hot spot map locate hot spots, for instance (the map is based on the MasterMap).
New layers of information are being added too, such as aerial photographic images that precisely match the mapping; data providing the addresses of all properties; and integrated transport information.
The new layers were launched in response to growing demand from mobile network operators, solution providers and software developers for flexible, high quality, consistent imagery mapping and integrated transport network (ITN) information throughout Great Britain. The first release of the ITN layer comprises Roads Network and Road Routing Information themes: The Roads Network theme features four million links that interact with the 400 million features of OS MasterMap, each link representing the precise alignment of every road in Britain and including digital information on the type and nature of each stretch of road.
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