The SM9819 Square Kilometre

SM9819 National Grid Square

Based in the Mid and West Wales region of Scotland.

SM9819 is within the post town of Haverfordwest, Pembrokeshire.

The square is within Sir Benfro - Pembrokeshire council.

The Point of Origin (0,0) is 295.24 Kilometres away. This is where the National Grid starts around 80 kilometres west of the Isles of Scilly.

Ordnance Survey Maps for SM9819

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Map Series	link	Ordnance Survey
Explorer 1:25,000 ol36 South Pembrokeshire	Shop for this map on amazon.co.uk	Buy Direct from the Ordnance Survey
Explorer 1:25,000 ol35 North Pembrokeshire	Shop for this map on amazon.co.uk	Buy Direct from the Ordnance Survey
Landranger 1:50,000 157 St Davids & Haverfordwest	Shop for this map on amazon.co.uk	Buy Direct from the Ordnance Survey
Landranger 1:50,000 158 Tenby	Shop for this map on amazon.co.uk

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 SM9819 and the vertical and horizontal line divides the square into four quadrants

Dividing the SM9819 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. SM , 98 and 19

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 SM + 98 + 3 + 19 + 5 would give you the six figure grid reference of SM983195

SM	98		19
SM	98	3	19	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	51.833001	-4.933777	198000	219000
South East Corner	51.833001	-4.918700	199000	219000
North West Corner	51.842341	-4.933777	198000	220000
North East Corner	51.842341	-4.918700	199000	220000