Posts Tagged ‘meridian’

Meridian 3

Friday, August 28th, 2020

Following the Greenwich Meridian is rather easier since the Ordnance Survey helpfully added it to their 1:25000 maps in 1999, but these pictures were made five years earlier in my project in preparation for the Millennium. I’d had to draw my own pencil line in their maps, which fortunately did show in their outer margins the Longitude at one minute intervals, including 0°00′, so it wasn’t hard to add the line.

I’ve never quite understood why the National Grid doesn’t quite align with this, the Prime Meridian, but presumably there were good reasons for choosing another starting point and working very slightly at an angle. The street maps which I needed to work out my actual route as they had the street names follow the National Grid, though they rather hide this behind their own system of letters and numbers based on half-kilometre squares.

For the northern part of my walk, the Meridian ran roughly down the gap between two pages of my Master Atlas of Greater London, a book too large and heavy to carry on my walks, and I marked out my route with highlighter pens on illegal photocopies of its pages.

There are several crossings of Southend Road, the North Circular Road at this point close to the Meridian which I think was actually a few yards to my east as I took a picture looking roughly west. But the road layout had changed a little from that since my OS map had been revised. It was a view which made a better picture – and close enough to the line for me, as was the level crossing at Highams Park – where again the actual line is a few yards behind me – to the west.

The view of Mapleton Rd and Stapleton Close (wrongly titled Mapleton Drive in my notes) is perhaps a hundred yards west of the Meridian, but close enough for me. The war memorial at the junction of The Ridgeway and Kings Head Hill is spot on target, while Woodberry Way is perhaps around a hundred yards to the west.

Finally, Pole Hill has two markers; the obelisk, set up by the Astronomer Royal to align his telescope in Greenwich due north is on the old Meridian, but the trig point to its left is on the version adopted internationally (except by France) in 1884. Nowadays we use GPS based on the International Terrestrial Reference Frame which has its zero meridian 102.478 metres further east.


All photographs on this and my other sites, unless otherwise stated, are taken by and copyright of Peter Marshall, and are available for reproduction or can be bought as prints.