grid and area references

Grid & Area ReferencesGrid & Area References• It can be difficult to find places or features easily on a map.

• So far we have learnt that to find places on a street directory we use an alpha-numeric grid (e.g. B7)

• We also know that to find places on a larger scale, such as a world map we use Latitude & Longitude coordinates to help us find what we are looking for.

Topographic maps are large scale and we use these for Area and Grid references

So how do we locate features on a Topographic map?

• http://news.bbc.co.uk/2/hi/uk_news/wales/north_west/7824895.stm

• This BBC link details the importance of Grid References for emergency services to reach rural areas.

• We can locate places easily on a topographic map by using the maps gridlines.

• On a topographic map the vertical ( )lines are

called eastings because they increase in value as we move eastward.

• The horizontal ( ) lines are called northings because they increase in value as we move northwards.

Eastings

Northings

N

1818

1717

1616

1515

2222 2323 2424 2525 2626 2727

Area Reference• Features such as a small lake, quarry or village

are usually located by means of an Area Reference (AR)

• To find the (AR) of a feature we use the coordinate in the lower left-hand corner of the grid square in which the feature is located.

• You always read the easting first then the northing. (hint to remember E comes before N in the alphabet)

• An area reference always has 4 figures• Into the house and up the stairs” may help you

remember!!

EXAMPLE: AR3363

easting northing

Eastings

Northings

N

1818

1717

1616

1515

2222 2323 2424 2525 2626 2727

The Area Reference of the house is:

AR2317

Remember with (AR) you use the bottom left hand corner

What is the (AR) for:

The plane:

AR2215

The boy:

AR2316

Area references

21 22 23 24 25 26

39

38

35

36

37

A

Time now for a little test. FOUR squares are going to be highlighted and you have TEN seconds to write down the area reference for each square.

10 9 8 7 6

5 4 3 2 1

ACLICK to start.....

CLICK for the next square

Area references

21 22 23 24 25 26

39

38

35

36

37

A10 9 8 7 6

5 4 3 2 1

BCLICK for the next square

B

Area references

21 22 23 24 25 26

39

38

35

36

37

A10 9 8 7 6

5 4 3 2 1

CCLICK for the next square

C

B

Area references

21 22 23 24 25 26

39

38

35

36

37

A10 9 8 7 6

5 4 3 2 1

DCLICK for the next square

C

B

D

Area references

21 22 23 24 25 26

39

38

35

36

37

A

CLICK TO CHECK EACH

ANSWER

C

B

D

A = 2238

B = 2536

C = 2235

D = 2337

How did you get on?

Grid References• We can locate relatively small and more specific features

on map by using Grid Reference (GR). • (GR) locates the exact point on the grid.

• Unlike (AR), Grid Reference uses 6 figures.

-The first two numbers of each coordinate refers to the eastings and northings that surround the map.

- The third number needed to complete each coordinate is obtained by dividing each easting and northing into tenths.

Example: GR335638

easting northing

Dividing the easting and northing into tenths

EastingsNorthing

N

1818

1717

1616

1515

2222 2323 2424 2525 2626 2727

What is the grid reference (GR) for the ball in which the boy is about to catch?

Answer:

GR238169

Come up to the Interactive White Board

Compass Directions

21 22 23 2466

67

68F

A

BGC

H

E

ID

J

N

E

S

W

NW NE

SESW

What direction are you walking ?

D F H I JGA C EB A

Interactives

• http://mapzone.ordnancesurvey.co.uk/mapzone/PagesHomeworkHelp/maptivity/gridreferences/

• http://geographyfieldwork.com/TestGridIntro.htm

CLASS EXERCISE

Give the (AR) for the following features:

1. Church;

2. Village Hall;

3. Grove farm;

4. The dairy farm;

5. The town of Little Plumpton;

6. The entire (AR)’s for Gibbet Wood;

7. The (AR)’s that Dale Road passes through;

8. The approximate (GR) of Grove farm.

Interactives

• http://www.mape.org.uk/startower/maps/resources/map1.htm

• http://www.mape.org.uk/startower/maps/resources/map1b.htm