The ST3915 Square Kilometre

ST3915 National Grid Square

Based in the South West English Region.

The ST3915 square kilometre intersects with the settlement of Seavington St Mary.

ST3915 is within the post town of Ilminster, Somerset.

The square is within South Somerset District council.

The Point of Origin (0,0) is 357.97 Kilometres away. This is where the National Grid starts around 80 kilometres west of the Isles of Scilly.

Ordnance Survey Maps for ST3915

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Map Series	link	Ordnance Survey
Explorer 1:25,000 128 Taunton and Blackdown Hills	Shop for this map on amazon.co.uk	Buy Direct from the Ordnance Survey
Explorer 1:25,000 129 Yeovil and Sherbourne	Shop for this map on amazon.co.uk	Buy Direct from the Ordnance Survey
Landranger 1:50,000 193 Taunton & Lyme Regis	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 ST3915 and the vertical and horizontal line divides the square into four quadrants

Dividing the ST3915 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. ST , 39 and 15

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 ST + 39 + 3 + 15 + 5 would give you the six figure grid reference of ST393155

ST	39		15
ST	39	3	15	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	50.931201	-2.869565	339000	115000
South East Corner	50.931201	-2.855169	340000	115000
North West Corner	50.940298	-2.869565	339000	116000
North East Corner	50.940298	-2.855169	340000	116000