map grids

Grids and Geographic Coordinates

Grids and grid coordinates

The geographic grid systemwas created to locate allplaces on Earth.

It uses latitude andlongitude to describe the location of any place on Earth.

One way of mappingthe world is on a globe,because Earth is a sphere,which is a 3D shape.

A map is usually a 2D drawing, and shows an accurate image of a place.

Most people find 2D mapseasier to use than globes.

Grids and geographic coordinates are used to locate places on a map.

Grids are evenly spaced horizontal and vertical lines placed on a map.

Letters or numbers are placed along the sides of a grid. They are combined to give grid coordinates for any location.

When have you had to locate places on a map?When have you had to locate places on a map?

Why is it useful to be able to quickly locate places on a map?

Maps in atlases and street directories are common examples of where you might use grid coordinates.

On this map, the grid coordinates are alphanumeric.

Alphanumeric means

a combination of letters and numbers.

Alphanumeric means

a combination of letters and numbers.

On this map, the grid coordinates are alphanumeric.

What common type of map generally

uses alphanumeric coordinates?

What common type of map generally

uses alphanumeric coordinates?

Locate the sports oval at Blair College.

The oval is easily located within the square bounded by the grid coordinates.

The grid coordinate is C3.

Note that the coordinate for the horizontal grid lines is given first, and the vertical grid coordinate second.

List one or two features that appear at the grid coordinates.

Answer – Church,Blair Rd/High St intersection

Answer –Bowling alley, houses

Answer –Tent shop, houses

Give the grid coordinates for the doctor.

Answer –B1

Give the grid coordinates for the fire station.

Answer –F1

Give the grid coordinates for the hospital.

Answer –C2

Answer –D4

Give the grid coordinates for the corner of Brown Street and Blair Road.

Eastings, northings and area references

This diagram uses a different type of grid system.

It is made up of numerals located on grid lines.

The numbers that refer to the vertical grid lines are called eastings.

They increase in value as you move across in an easterly direction.

The numbers that refer to the horizontal grid lines are called northings.They increase in value as you move up in a northerly direction.

The two eastings numbers are joined with the two northings numbers to make a four-figure area reference.

For example, a % symbol is located at eastings 46 and northings 22, so its area reference is 4622.

Which symbol appears at these area references?

Answer –

Grid references

Grid references locate places on a map more accurately than area references.

A grid reference is a six figure number, made up of a three-figure eastings reading and a three-figure northings reading.

A grid reference is found by mentally subdividing each grid square into tenths.

The third figure in each eastings and northings reading is found by estimating how many tenths across or up the exact location is.

Grid references

What is the grid reference for the Post Office?

Answer – 283579

Grid references

Name the feature at 280570.

Answer – An island

Grid references

Name the feature at 258576.

Answer – The river mouth

Grid coordinates – latitude and longitude

To locate different places around Earth, we use geographic coordinates – measurements of latitude and longitude.

Lines of latitude are imaginary parallel lines that circle the globe in an east–west direction.

The Equator divides Earth into northern and southern hemispheres.

Latitude measures how many degrees north or south a point on Earth lies from the Equator.

What is the name given to the imaginary line of latitude at:

Tropic of CapricornTropic of Capricorn

23.5O south of the Equator?

23.5O north of the Equator?

Tropic of CancerTropic of Cancer

66.5O south of the Equator?

Antarctic CircleAntarctic Circle

66.5O north of the Equator?

Arctic CircleArctic Circle

Lines or meridians of longitude are imaginary lines between the North and South Poles.

Longitude measures how many degrees east or west a point on Earth is from the Prime Meridian.

The Prime Meridian is the meridian of longitude at 0O. It divides Earth into eastern and western hemispheres.

What is the name given to the imaginary line at 180O from the Prime Meridian?

International Date LineInternational Date Line

Find out why it is given this name.Suggest why it is this shape.Find out why it is given this name.Suggest why it is this shape.

International Date LineInternational Date Line

The exact location of any place on Earth is given by its geographic coordinates.

You can find examples in the index of your atlas.

Measurements for latitude and longitude are given in degrees (and minutes).

Latitude is stated first, then longitude.

Sydney’s geographic coordinates are: 33.52S 151.10E

Tokyo’s geographic coordinates are: 35.40N 139.45E

Washington’s geographic coordinates are:38.55N 77.00W

Washington

Cairo’s geographic coordinates are:30.03N 31.15E

Cape Town’s geographic coordinates are:33.56S 18.28E

Cape Town

Geographic coordinates and alphanumeric references are used in the index of an atlas.

One atlas gives Sydney’s reference as Map 50 J12 33.52S 151.10E.

To locate a place in your atlas, check:

• the map number

• the grid

• geographic coordinates – latitude first, then longitude.

Latitude and longitude quiz

What is maximum number of degrees it is possible to move north of the Equator?

Answer – 90O

What is this point called?

Answer – The North Pole

What is maximum number of degrees it is possible to move south of the Equator?

Answer – 90O

What is this point called?

Answer – The South Pole

Fill in the gaps.

Lines of longitude are used as the basis of the world’s _____ zones. They measure degrees _____ and west of the ______ Meridian.

The _______ measurement is always given first, followed by the _________ measurement. Measurements are in _________ and minutes.

latitude degrees time longitude east Prime

latitudelongitude

degrees

Primeeast

Atlas activities

You need an atlas for these activities.

Atlas activity

Name the continent that includes a place at these geographic coordinates: 30OS 120OE

AustraliaAustralia

Atlas activity

Name the continent that includes a place at these geographic coordinates: 60ON 120OW

North AmericaNorth America

AustraliaAustralia

Atlas activity

Name the continent that includes a place at these geographic coordinates: 90OS 180O

AntarcticaAntarctica

AustraliaAustralia

Atlas activity

Name the continent that includes a place at these geographic coordinates: 0O 30OE

AfricaAfrica

AustraliaAustralia

AfricaAfrica

Atlas activity

Use your atlas to find the capital cities of Australia’s states and territories.

List the latitude and longitude for each one.

Darwin

Canberra

Brisbane

Adelaide

Atlas activity

34.52S, 138.30E34.52S, 138.30E

Darwin

Canberra

Brisbane

Adelaide

Atlas activity

34.52S, 138.30E34.52S, 138.30E

Darwin

Canberra

27.25S, 153.02E27.25S, 153.02E

Brisbane

Adelaide

Atlas activity

35.15S, 149.08E35.15S, 149.08E

34.52S, 138.30E34.52S, 138.30E

Darwin

Canberra

27.25S, 153.02E27.25S, 153.02E

Brisbane

Adelaide

Atlas activity

35.15S, 149.08E35.15S, 149.08E

34.52S, 138.30E34.52S, 138.30E

12.25S, 130.51E12.25S, 130.51E

Darwin

Canberra

27.25S, 153.02E27.25S, 153.02E

Brisbane

Adelaide

Atlas activity

Sydney

Melbourne

Hobart

Atlas activity

42.50S, 147.21E42.50S, 147.21E

Sydney

Melbourne

Hobart

Atlas activity

37.50S, 145.00E37.50S, 145.00E

42.50S, 147.21E42.50S, 147.21E

Sydney

Melbourne

Hobart

Atlas activity

37.50S, 145.00E37.50S, 145.00E

31.57S, 115.52E31.57S, 115.52E

42.50S, 147.21E42.50S, 147.21E

Sydney

Melbourne

Hobart

Atlas activity

37.50S, 145.00E37.50S, 145.00E

31.57S, 115.52E31.57S, 115.52E

42.50S, 147.21E42.50S, 147.21E

Sydney

33.53S, 151.10E33.53S, 151.10E

Melbourne

Hobart

Atlas activity

Order the capitals from north to south.

Sydney 33.53S, 151.10ESydney 33.53S, 151.10E

Hobart 42.50S, 147.21EHobart 42.50S, 147.21E

Brisbane 27.25S, 153.02EBrisbane 27.25S, 153.02E

Darwin 12.25S, 130.51EDarwin 12.25S, 130.51E

Adelaide 34.52S, 138.30EAdelaide 34.52S, 138.30E

Canberra 35.15S, 149.08ECanberra 35.15S, 149.08E

Melbourne 37.50S, 145.00EMelbourne 37.50S, 145.00E