Four and 6 Figure grid reference

How do grid references help me find places?

It is easy to find a particular place using a grid reference. To start, a four-figure grid reference is a handy way of identifying any square on a map. 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 square first use the eastings to go along the corridor until you come to the bottom left-hand corner of the square you want.

On many maps one can see a number of vertical and horizontal lines. These line crisscross each other to form a neat pattern of squares known as a grid. This grid covers the entire map. Take a look at the grid below. It is similar to the ones you will see on a typical map.

The vertical lines, which run from north to south (e.g. 21 and 22) , are known as eastings.  The horizontal lines, which run from east to west (e.g. 45 and 46), are known as northings. Every easting and northing has its own two digit number which can be found at either end of it. Eastings increase in value as one moves to the right (toward the east) on the map. Northings increase in value as one moves toward the top (the north) of the map. Each square on the grid is known as a grid square. One can give the location of an object or objects on a map by naming the grid square in which it is located. Lucky for you, it is a very simple process.

Giving a Four Figure Grid Reference

Look at the grid below. One square has been shaded. How can you easily identify this square?

A simple way is to give the four figure grid reference for that square. This is done by stating the number of the easting which runs along the left side of the square (in this case 22) followed by the number of the northing which runs along the bottom of it (in this case 47). Therefore 2247 is the four figure grid reference for this entire grid square or anything inside of it. It is important to note that the easting must always be stated first, followed by the northing. Simply put, the vertical line comes before the horizontal line, like when you write a capital “L”. Also you must not leave a space between the easting and the northing. Furthermore, a grid reference must not contain dots, commas, hyphens (or any other crazy stuff for that matter).

In other words, the four figure grid reference for the square shaded in the grid above or anything which is inside of that square is simply 2247.

NOT  22    47  (This is wrong as there should be no space between the 22 and the 47)

NOT 22,47 (This is wrong because a grid reference should not contain commas)

NOT 22.47 (This is wrong because of the dot)

NOT 22-47 (You get the point right? Good! Let’s move along.)

Always remember, that to give the four figure grid reference for an object, you must state the number of the easting immediately to its left followed by the northing directly under it.

Useful tip: If an easting or northing crosses an object, then that easting or northing will form part of the four figure grid reference for that object. For instance, if easting 22 crosses over an object such that part of the object is in grid square 2247 and the other part is in grid square 2147, then the four figure grid reference for that object would be 2247.

Examples: Write this two-figure number down. Then use the northing to go up the stairs until you find the same corner. Put this two‑figure number after your first one and you now have the four-figure grid reference, which looks like the example in diagram D: 6233.

Four figure grid references are indeed very useful. However, a major weakness of four figure grid references is the fact that they are not very accurate. All objects in the same grid square have the same four figure grid reference even though they may be hundreds of meters apart . When greater accuracy is necessary, a six figure grid reference is used.A six figure grid reference does not only indicate the grid square an object is located in. It also tells us the exact point within the grid square where the object is found. Therefore, objects located in the same grid square will have the same four figure grid reference, but different six figure grid references.

How to Give a Six Figure Grid Reference

A six figure grid reference takes the form EEXNNY. EE represents the easting which is immediately to the left of the object and NN represents the northing which is directly under it. Therefore EE and NN represent the four figure grid reference for the object in question. X is a digit which tells us how close to or far away from the easting the object is located. The higher the number, the farther away from the easting the object is. Similarly, Y is a digit which tells us how close to or far away from the northing the object is found. X and Y can have a value ranging from zero to nine. Look at the grid square below. Look at the letter “A” located within the square. The four figure grid reference for “A” is 2345. However, 2345 is also the four figure grid reference for any object which lies anywhere in this grid square. We can give the exact location of this “A” by giving a six figure grid reference. Let us take it step by step.

Step 1

Remember a six figure grid reference takes the form EEXNNY. The first two digits represent the easting immediately to the left of the object. The easting to the left of “A” is 23, therefore we have our first two digits. The third digit (X) represents the distance between easting 23 and “A”. To determine this we need to divide the space between easting 23 and easting 24 into ten equal parts as seen in the diagram below.

The lines are parallel to our easting are an equal distance apart from each other. Let’s call these lines “mini eastings”. Now we need to count the number of mini eastings that are between easting 23 and “A”. In this case there are four. Therefore our third digit is 4. So the first part of our six figure grid reference is 234.

Step 2

The fourth and fifth digits in a six figure grid reference represent the northing which is directly under the object. In this case it is northing 45. The sixth digit tells us the distance between northing 45 and the object. We must divide the space between northings 45 and 46 into ten equal parts as seen below.

Once again the lines are parallel to northing 45 and are an equal distance apart. Let us call these lines “mini northings”. We must count the number of mini northings which are between northing 45 and “A”. In this case there are seven of them. Therefore 7 will be the last digit in our six figure grid reference. The second part of our grid reference is 457.

Our entire six figure grid reference is 234457. Remember:

• the first two digits represent the easting immediately to the left of the object( in this case easting 23).
• the third digit (4) represents the distance between the easting and our object. In this case the object is roughly four tenths of the distance between easting 23 and easting 24.
• the fourth and fifth digits represent the northing directly under our object (in this case northing 45)
• the sixth digit represents the distance between the northing and our object. In this case, the object is roughly seven tenths of the distance between northing 45 and northing 46.

Note: If the position of “A” was such that it lay directly on mini easting 4 or mini northing 7, its six figure grid reference would still be 234457. 

The two steps shown above need not be done separately. Your “mini eastings” and “mini northings” can be drawn such that they form a smaller grid inside the grid square in which the object is located. The six figure grid reference can be completed by giving the number of the mini easting immediately to the left of the object and the number of the mini easting directly under it (see below).

The six figure grid reference is 234457

If you want to pinpoint an more exact place on a map, such as your own house, you will need to use a six-figure grid reference. First find the four-figure grid reference for the square and write it down with a space after each set of numbers, like this: 62_ 33_

Now imagine this square is divided up into 100 tiny squares with 10 squares along each side. Still remembering to go along the corridor and up the stairs, work out the extra numbers you need and put them into your four-figure grid reference like this in diagram E: 625 333.

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