Feb/Mar 2008

Ordnance Survey has joined the ranks of digital map producers that have made their mapping available in a form suitable for Web site 'mash-ups'. The concept is similar to that of the now-familiar Google system, where a given Web site can have embedded links to Google in order to display relevant maps on screen to users.

Ordnance Survey is calling its new service OS OpenSpace. It's free for non-commercial applications, though commercial users need to obtain a suitable licence. And it's now available to developers and alpha (mature) test mode.

The key to the service is a new JavaScript-based API (application programming interface), which enables developers to include draggable AJAX-style maps in their Web applications. This approach has come to be seen as a quintessential feature of many so-called Web 2.0 applications, though actually this term has no specific meaning.

Up to 30,000 map 'tiles' or extracts of data and up to 1,000-placename look-ups can be accessed by a given application in a day. Users can add markers, lines and polygons on top of the OS mapping, as well as searching for place names with a gazetteer. They can also display other location data from elsewhere on the Web.

 

The mapping incorporates a variety of existing OS map layers, which are selected automatically according to zoom level. They include 1:250 000 scale colour raster, 1:50 000 scale colour raster and OS Street View, plus a gazetteer of 250,000 placenames.

The opening up of OS mapping for free use is seen as a significant step in the organisation's history. It has always trodden a delicate path between fairly aggressive commercial map pricing and its public obligation as the UK's cartographic resource, and this appears to be one instance where the public benefit has come to the fore. But the firm restrictions on commercial use qualify this concession.