grid & area references

12
Grid & Area References Grid & 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.

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Grid & 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) - PowerPoint PPT Presentation

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Page 1: Grid & 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.

Page 2: Grid & Area References

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

Page 3: Grid & Area References

So how do we locate features on a Topographic map?

• 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.

Page 4: Grid & Area References

Eastings

Northings

N

1818

1717

1616

1515

2222 2323 2424 2525 2626 2727

Page 5: Grid & Area References

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

EXAMPLE: AR3363

easting northing

Page 6: Grid & Area References

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

Page 7: Grid & Area References

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

Page 8: Grid & Area References
Page 9: Grid & Area References

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

Page 10: Grid & Area References

Interactives

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

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

Page 11: Grid & Area References

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.

Page 12: Grid & Area References

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

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