How to take a grid reference? There are several ways of taking a grid reference. A 6-figure grid reference can be found using a map. To do this you need to identify the horizontal lines called ‘northings’ and vertical lines called ‘eastings’. These are located at every 1 km interval on a map creating a series of squares covering the UK and each 1x1 km square is called a monad. Grid references are easy if you can remember that you always have to go along the corridor before you go up the stairs. To find the number of a monad, first use the eastings to go along the corridor until you come to the bottom left-hand corner of the monad you want. Write this two-figure number down. Now imagine this monad is divided up into 100 tiny squares with 10 squares along each side. Still remembering to go along the corridor mark down the number of small squares where your point falls. This creates the first three digits of a grid reference. To create the next three digits repeat this process using the northings to go up the stairs until you find the same corner of the monad. Mark down these two numbers and then imagine the monad is spilt into 100 tiny squares with 10 squares along each side. Still remembering to go up the stairs mark down the number of small squares where your point falls. To get the two letter code for the front of the grid reference look at the corner of the map. The UK is split into 100x100 km squares and each of these huge squares is given a code so that it can be located across the country. Altogether this creates the grid reference i.e. Stonehenge is at SU122422. Ordinance Survey have produced a graphical guide to taking a grid reference available at https://www.ordnancesurvey.co.uk/docs/leaflets/using-the-national-grid-leaflet-for-children.pdf. An alternative way to get a more detailed grid is to use a handheld GPS unit. These can give up to 10 figure grid references with varying degrees of accuracy depending on the satellites available. Each GPS unit is different, and you may need to read the instructions to find out how to use it. There are good mobile apps that can provide a 6, 8 or 10 figure grid reference1

• GPS to Grid Ref (green icon with OS on it). It currently costs £0.79 but will convert long & lat from the phone's internal navigation into a 10 figure OS grid reference.

. For Windows Phones (and tablets);

• Grid Ref UK and Ireland (UK map icon) which will give you a 6 figure OS grid reference and is free.

For Android and iPhones (and tablets);

• OS Mapfinder (map with the OS logo on top) will project your location onto an OS map at a large scale (more detailed maps can be downloaded for a fee). By pressing on the icon hovering on your position you can get a 10 figure grid reference. This app and small-scale maps are free but more detailed maps are charged extra. However, these should not be needed to create a 6 figure OS grid reference.

All of these apps use satellite technology so you do not need to be in mobile reception to get a grid reference, but where satellite access is restricted, such as under a tree canopy in a woodland, in gorges and tunnels etc., they may not be able to connect to a satellite to provide a grid reference, or the grid reference may be inaccurate.

1 Apps sourced on 1st February 2015. Newer or alternative apps may be available.

Diagram A

SZ

NZNYNXNW

NUNTNSNR

NONNNMNL

NKNHNGNFNDNCNBNANJ

TQ

SM TL TMSN SPSO

TFSKSJSHTASESDSC

SR SS SUST TR

SV TVSW

HP

SYSX

TG

HZHYHXHW

HUHT

400

300

200

100

700

900

600

500

800

1000

1200

1100

400 600100 300200 5000

0

Diagram C

35

70

31

33

34

36

37

38

6560 61 62 63 6964 66 67 68

35

30

31

32

33

39

34

36

37

38

39

4040TL

TL TL

TL

30

TL6332

Diagram B

5

1

3

4

6

7

8

50 1 2 3 94 6 7 8

5

0

1

2

3

9

4

6

7

8

9

0

south-westcorner

TL2

northing

s ▶

eastings ▶

TL63

1 The National Grid provides a unique reference system, which can be applied to all Ordnance Survey maps of Great Britain, at all scales.

2 Great Britain is covered by 100 kilometre grid squares, each grid square is identified by two letters, as shown in diagram A.

3 On Ordnance Survey maps these squares are further divided into smaller squares by grid lines representing 10 kilometre spacing, each numbered from 0 to 9 from the south-west corner, in an easterly (left to right) and northerly (upwards) direction, as shown in diagram B.

5 On an OS Landranger Map you can find the two grid letters TL on the legend, or on the corner of the map, and the grid has been further divided into 1 kilometre intervals, as shown in diagram C.

4 Using this system you can identify a 10 kilometre grid square. For example, here is TL63. After the letters you quote the eastings (6) first, then the northings (3).

If you have trouble remembering, say… stairs the up Along the hall, THEN

6 You can estimate distances between the grid lines to give a more precise reference. Turn the page and see how easy it is to use a six-figure grid reference to pinpoint a place on the map…

Using the National Grid

7 The six-figure grid reference is very useful to locate a particular place on a map.

8 By estimating the eastings and northings to one tenth of the grid interval, you can specify a full six-figure grid reference, accurate to within 100 metres on the ground.

9 All you do is estimate how many tenths away from the grid your point falls. For instance, the point in diagram D is three tenths east of grid 62 and seven tenths north of grid 31.

10 Once again, reading from the south-west corner, quote all the eastings first, then the northings. The 100-metre grid reference of the point in the diagram is shown like this: TL 623317.

11 Here is an extract from a 1:50 000 scale map. Use the National Grid reference system to find:

The Church at TL683365 The Windmill at TL726350 Mill Farm at TL701352

Map extract from OS Landranger Map Sheet 154.

Diagram D

35

70

31

33

34

36

37

38

6560 61 62 63 6964 66 67 68

35

30

31

32

33

39

34

36

37

38

39

4040TL

TL TL

TL

30

seventenths

threetenths

south-westcorner

TL6332

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The six-figure grid reference