4th Royal Eltham



Grid References

Grid References - Quick guide




















Grid References

You need to tell someone how to get from one place to another. Sounds easy enough and if you were at the bottom of the street where you live and, you were directing someone to the nearest public telephone you could probably do a pretty good job without a map.

But imagine you've just been left in the middle of a field and given a piece of paper, a compass and a collection of maps. On the paper is written the following;

(Start) TQ083305

(Finish) TR127336

Off you go then, dinners at eight! However, if your not too sure about what the letters and numbers mean read on and I'll try to explain. Ordnance Survey maps are all about squares and tens, if you remember that your well on your way.

The big Squares

Take a very big photograph of the British Isles (or anywhere else for that matter) and cut it up into big squares. To identify all those squares you could give each one a name like Fred, Jim, Peter etc. but that would be too much fun! So instead you give each of them some letters.

So the letters at the beginning of all those numbers tell you which map to look at. Each map will have identification letters at the bottom of it near to where the symbols are explained, and some have them on the corners of the map as well. Take a look at an Ordnance Survey map and see if you can find them.

Now you have found the right map you need to find out where you are and where you are going to.

The small squares

Each map is divided into smaller squares by lines drawn from top to bottom, left to right. These lines are called grids.

If you look around the edges of our map (below) you will see that each line from top to bottom has a two digit number and so does each left to right line.  These are called grid reference numbers, they also appear on Ordnance Survey maps.

To help you, the large numbers on our map are coloured RED and BLUE.

It is important to remember that you always read the top or bottom (RED) number first followed by the left or right (BLUE) number.

Take a look at our map and see if you can find where the lines meet at this grid reference ; 3344.

....Continued below map

If you got that right you now have the basics. But the Grid Reference you have just found will only get you within a kilometre or so. To get closer you need some more detailed information.

The really small squares

This is done by dividing each square up into smaller squares. The problem is, these small squares are not shown on real maps, you have to "imagine" them.

The map above has one of it's grid squares divided by the extra lines and they are numbered to show you how to do it. You might notice that these numbers are coloured black or mauve.

Can you also see how the squares are divided and numbered?

From left to right.

31 1,2,3,4,5,6,7,8,9 32 1,2,3,4,5,6,7,8,9 33 1,2,3,4,5,6,7,8,9 34 1,2,3,4,5,6,7,8,9

From bottom to top

44 1,2,3,4,5,6,7,8,9 45 1,2,3,4,5,6,7,8,9 46 1,2,3,4,5,6,7,8,9

Try finding the yellow cross on our map at this grid reference 322452.

Can you see how important it is to use the top bottom numbers first then the left right numbers? If you get them in the wrong order you could end up somewhere else!

See if you can find the exact Grid Reference of the GREEN CROSS on our map, it should have six numbers and don't forget to read the top or bottom number BEFORE the left or right number. (click here to check your answer).

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Grid References - Quick guide

It may be helpful if you had an Ordnance Survey map to refer to

A grid reference normally consists of a six digit number like 337529. There may be letters at the beginning these numbers like TR337529.

To read the grid reference you must first of all break it down into sections.

If shown, the letters (TR) refer to the map that should be used. Each "OS" map has it's ID letters printed at the bottom by the symbol key.

Next, divide the six remaining numbers into two groups of three, 337 and 529.

The "33" refers to the numbers at the top and bottom of the vertical lines on an OS map and the 7 refers to a point towards the line to the right (34). If the third number was a 5 this would be half way between 33 and 34, got the idea?

The "52" refers to the numbers left and right of the horizontal lines and the 9 refers to a point towards the line above (53). If the third number was a 5 this would be half way between 52 and 53.

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The answer should be


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