Leading article: Lines on a map

There is something intoxicatingly romantic about an old Ordnance Survey map. They are redolent of the aromas of childhood; not just the musty smell of an ancient linen-backed tourist edition, but the way the gently water-coloured lines rise up in brown peaks from green valleys.

But they are precision tools of the present too, as a modern 1:50,000 map of any contemporary British city will show, which is why the OS website nearly went into meltdown yesterday when the public was allowed free and unrestricted access to most of its maps online for the first time.

It was a belated development. With Google Earth, MultiMap, Street View and the rest, there is so much mapping information already available on the internet free of charge that ministers had little choice but to waive our public maps' long-guarded copyright. The result is a delight to any map junkie – and a serious business opportunity to an entrepreneur with a scintilla of imagination.