Speaker Jon Bagnall
History: Britain’s mapping agency has its roots in military strategy: mapping the Scottish Highlands following rebellion in 1745. With William Roy being tasked to produce a map of Scotland which he and his team managed in six years.
Later the board of Ordnances tasked him with mapping the whole country to do this Roy asked the leading instrument maker Jesse Ramsden to produce an instrument for measuring angles both horizontally and vertically so in1791 the Ordnance Survey was born. It was ordered that the South of England be mapped for that efficient defensive positioning of our armies.
Understanding the map: The OS grid.
For today's maps the country has been split up into 100km squares each having a two letter code. These squares are split up into kilometre squares so a six digit reference can be used to define anywhere in the country. SU0745758 is where the underground station for Heathrow Terminal 1 is to within 100m. Eight digits can be used for greater accuracy!
On moorland it is more difficult to recognise features to be sure of your location and I hope to give some pointers on how to keep on track.