GRID REFERENCES MADE EASY Produced by David Morris.

Post on 15-Dec-2015

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GRID REFERENCESMADE EASY

Produced by David Morris

A GRID REFERENCE is a number which gives a location on a map

They are very useful in Scouts when we’re out hiking

We can use them to find out where we’re supposed to be…

...or if we get lost we can tell someone where we are

The grid references we usually use are SIX FIGURE references

They will look something like this:

216409A bit like a phone number

These numbers refer to the GRID which covers all maps

Here they’re marked in PINK so you can see them, but they’re usually BLUE

The grid is labelled with GRID NUMBERS at the bottom and left sides of the map

20 21 22 2340

41

42

20 21 22 23

The numbers at the bottom are called EASTING because they show how far East you are. They label these lines…

The numbers at the side are called NORTHINGS because they show how far North you are . They label these lines…

40

41

42

21

Each Easting refers to the column to the right of it’s grid line

Each Northing refers to the row above it’s grid line

40

Where are these EASTINGS and NORTHINGS in the Grid Reference?

21640921 40EASTING NORTHING

Both numbers combined give a square on the map...

4021

The grid reference of this square is 21 40

How do you remember WHICH COMES FIRST though?

EASTINGS FIRSTEASTINGS FIRSTOne way of remembering is to read the numbers ALONG the bottom (EASTINGS) and then those UP the side (NORTHINGS) because you go ALONG the hallway in a house before going UP the stairs

EXERCISE ONEFIND THE SQUARE

You’ll have a map between two, and a list of 6 figure grid references - just find the big square for each one

EXERCISE ONEFIND THE SQUARE

You’ll have a map between two, and a list of 6 figure grid references - just find the big square for each one

OK so we now know how to find the square from these numbers:

21640921 40But what about these ones?

6 9

What are they for?

Well the 40 and 21 only give you a big square one kilometre wide!

4021

Not much use if you need to know where to go exactly!

1km

So we split each square into 100 smaller squares...

Each square is labelled like the grid before, but with just one number from 0 to 9

0 1 2 3 4 5 6 7 8 9

9876543210

So, same as before, a square is identified by an EASTING and a NORTHING

Remember, EASTING first

0 1 2 3 4 5 6 7 8 9

9876543210

So what’s the two numbers which identify this square?

That’s right: 4 and then 7

4 first as it’s the EASTING

0 1 2 3 4 5 6 7 8 9

9876543210

Then 7 as it’s the NORTHING

0 1 2 3 4 5 6 7 8 9

9876543210

OK, let’s put it all together…

See the spot height marked 375 in the square below?

20 21 22 2340

41

42

Let’s find out it’s full 6 figure reference

_ _ _ _ _ _First, what square is it in?

20 21 22 2340

41

42

20 21 22 2340

41

42Yes, 21 - 40

But where does this fit into the 6 figure reference?

20 21 22 2340

41

42

2 1 _ _ _ _21 first

20 21 22 2340

41

42

2 1 _ 4 0 _Then 40

20 21 22 2340

41

42

Both together... 2 1 _ 4 0 _

20 21 22 2340

41

42 Now we need to look at the missing two figures:

2 1 _ 4 0 _

20 21 22 2340

41

422 1 _ 4 0 _So we add the grid - usually you do this in your mind

20 21 22 2340

41

422 1 _ 4 0 _The spot height is in this square

Zooming in...

0 1 2 3 4 5 6 7 8 9

9

8

7

6

5

4

3

2

1

0

2 1 _ 4 0 _22

2

2

20 21 22 2340

41

42 So now we have the full grid reference:

2 1 2 4 0 2

20 21 22 2340

41

42

OK, what about the station in Llangollen?

_ _ _ _ _ _

20 21 22 2340

41

42

Answer:

214422

20 21 22 2340

41

42

OK, where’s this one...

204408

20 21 22 2340

41

42204408 Answer: Bank Fm

EXERCISE TWOPRACTISE MAKES PERFECT

You’ll have a map between two, challenge each other to give the grid ref for a place, and the places for given refs

EXERCISE TWOPRACTISE MAKES PERFECT

You’ll have a map between two, challenge each other to give the grid ref for a place, and the places for given refs