Ben Nevis Grows A Metre

Ben Nevis, Britain’s tallest mountain, is a metre taller than we thought based on recent GPS height measurement.

16:44 22 March 2016

The Ordnance Survey (OS) has re-measured Ben Navis using modern technologies that enhance precision, setting the official measurement of the Scottish peak at 1,345m, a metre taller than before. OS, Britain’s official mapping agency, has already begun issuing maps with the new height.

 

The agency's geodetic consultant, Mark Greaves, said: "Initially, I thought, 'Well, it's just a number', but then I took a look at the map and thought, 'Oh my, I've just raised the height of the tallest mountain in Britain.”

"And then of course your next reaction is to check and double-check. I had to make sure we'd got it absolutely right,"

 

Ben Nevis was measured more than 60 years ago by a team that hauled heavy gear up to the mountain and nearby peaks. They positioned trig pillars to work out elevations by deriving angles from a system of national benchmarks.

 

Today, however, remarkable levels of precision can be achieved using Global Positioning System technology.

"The GPS in your phone can be out by several metres," explained Mr Greaves. "That's because there are errors in the signals coming down from the satellites.

 

"We have to filter those out, and one of the ways we do that is to compare the data we get on the mountain with highly accurate, permanent GPS stations nearby.

 

"And if you do it to a high enough degree with some very sophisticated software, you get down to centimetres and better."