The SO1940 Square Kilometre

SO1940 National Grid Square

Based in the Mid and West Wales region of Scotland.

SO1940 is within the post town of Hereford, Herefordshire.

The square is within Powys - Powys council.

The Point of Origin (0,0) is 399.20 Kilometres away. This is where the National Grid starts around 80 kilometres west of the Isles of Scilly.

Ordnance Survey Maps for SO1940

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Map Series	link	Ordnance Survey
Explorer 1:25,000 ol13 Brecon Beacons National Park - Eastern area	Shop for this map on amazon.co.uk
Explorer 1:25,000 188 Builth Wells, Painscastle and Talgarth	Shop for this map on amazon.co.uk
Landranger 1:50,000 148 Presteigne & Hay-on-Wye	Shop for this map on amazon.co.uk	Buy Direct from the Ordnance Survey
Landranger 1:50,000 161 Abergavenny & The Black Mountains	Shop for this map on amazon.co.uk	Buy Direct from the Ordnance Survey

This extract is taken from the Ordnance Survey six-inch to the mile series surveyed from 1888-1913. The scale is 1:10,560.

The Square overlayed over the map represents the extent of SO1940 and the vertical and horizontal line divides the square into four quadrants

Dividing the SO1940 Square to get a six figure Grid Reference

A helpful reminder for calculating grid references is across the landing and up the stairs.

For example if your house was located in a square that in the fourth square across and sixth square up and you wanted to work out its six figure grid refence.

First, You would divide the four figure grid reference into three parts. SO , 19 and 40

Count across starting with zero. This would give you three. Make a note that X for Across (A Cross) = 3.

Count up starting with zero. This would give you five. Make a note that Y = 5.

So to put it together SO + 19 + 3 + 40 + 5 would give you the six figure grid reference of SO193405

SO	19		40
SO	19	3	40	5

A six figure grid reference would be accurate to 10 metres. To achieve a greater level of accuracy this 10 metre square would be divided into a grid 10 by 10 and the process repeated.

This would produce an 8 figure grid reference that would be accurate to a square metre!

Corner	Latitude	Longitude	Easting	Northing
South West Corner	52.052450	-3.182912	319000	240000
South East Corner	52.052450	-3.168094	320000	240000
North West Corner	52.061585	-3.182912	319000	241000
North East Corner	52.061585	-3.168094	320000	241000