MAPPING OUR WORLD

MAPPING Cartography-

• science of map making

Maps*Flat models of 3-dimensional

spaces

**Earth is always distorted on maps

Typical Graph This is an example of a typical graph we are all

familiar with. The graph is made

up of different “points” with lines that connect the points.

The points are referenced to the x and y axis

Maps are Similar to Graphs

Let each of the four quarters be designated by North or South and East or West.

N

S

EW

What are the 0 points? Equator –

• Separates the Earth into two equal halves called the northern hemisphere and the southern hemisphere

• It is an imaginary belt that runs halfway point between the North Pole and the South Pole.

Equator

What are the O points? Prime Meridian –

• Divides the Earth running North -South• Separates the Earth into two

halves – the Eastern hemisphere and the Western hemisphere

• Goes through Greenwich, England – home of Royal Naval Observatory

P

R

I

M

E

MERIDIAN

East West, North South on the Earth

The N tells us we’re north of the Equator. The S tells us we’re south of the Equator.

The E tells us that we’re east of the Prime Meridian. The W tells us that we’re west of the Prime Meridian.

(N, W) (N, E)

(S, W) (S, E)

Latitude and Longitude The earth is divided into lots of

reference lines called latitude and longitude.

What is Latitude? Latitude is the distance

from the equator along the Y axis.

Lines running parallel to equator

Measures NORTH – SOUTH, but runs East-West

All points along the equator have a value of 0 degrees latitude.

North pole = 90°N South pole = 90°S Values are expressed in

terms of degrees.

Y

X

90°S

90°N

What is Latitude? Each degree of

latitude is divided into 60 minutes.

Each minute is divided into 60 seconds.

Ex: coordinates of Sunny Hills HS

33°52′48″N 117°55′43″W

Y

X

90°S

90°N

This is also true of longitude.

What is Longitude? Longitude is the distance

from the prime meridian along the X axis.

Lines running parallel to Prime Meredian

Measures EAST – WEST, but runs North-South

All points along the prime meridian have avalue of 0 degrees longitude.

The earth is divided into two parts, orhemispheres, of east and west longitude.

Y

X

180°W 180°E

What is Longitude? The earth is divided

into 360 equal slices (meridians)

180 west and 180 east of the prime meridian

Y

X

180°W 180°E

The Size of 1o

Latitude• degree of latitude is approximately 69 miles,

and a minute of latitude is approximately 1.15 miles

Longitude• A degree of longitude varies in size – it

decreases to zero as meridians come together at the poles

• At the equator, it is approximately 69 miles, the same size as a degree of latitude.

• At a latitude of 45 degrees, a degree of longitude is approximately 49 miles.

Coordinate System

Time Zones

The Earth is divided into 24 time zones • Each time zone is 15˚ wide • There are 6 different time zones in the U.S.

Rotation

The Earth rotates 15o of longitude every hour

24 lines of longitude (24 hours) in one day

15 x 24 = 360o total (full circle)• 180o longitude on each side of Prime

Meridian

International Date Line

The International Date Line, or 180˚ meridian, serves as the transition line for calendar days• If you were traveling west across the

IDL, you would advance your calendar one day.

• If you were traveling east across the IDL, you would move your calendar back one day.

See If You Can Tell In Which Quarter These Lon/Lats Are

Located 1. 41°N, 21°E 2. 37°N, 76°W 3. 72°S, 141°W 4. 7°S, 23°W 5. 15°N, 29°E 6. 34°S, 151°E

A B

C D

1. B 2. A3. C4. C5. B6. D

Mercator Projection Parallel lines of latitude and longitude

• Area of land masses near the poles are exaggerated

Used for navigation of planes and ships

Conic Projections Points and lines on a globe are

projected onto a cone-shaped paper. Little distortion in the areas or shapes

of landmasses that fall along this line of latitude• Distortion is evident near top and bottom ofthe projection

• Useful for road maps& weather maps

Gnomonic Projections

Points and lines from a globe are projected onto a paper that touches the globe at a single point. • Distort direction and distance between

landmasses Useful in plotting long-distance trips by air and sea

Topographic Maps

Topographic Map

Show changes in elevation of Earth’s surface

Also show, mountains, rivers, lakes, forests, etc.

Features of Topographic Maps

Relationship between 3D and 2D representation

3D view

2D view

Contour Lines • Contour lines drawn ona map give the elevations for a region.

• Where the lines are close, the slope of the ground is steep.

• Where the lines are farapart, the slope of the ground is gentle.

Contour Lines

Imaginary lines that connects points of equal elevation (height above sea level)

Contour Lines

contour lines do not intersect, branch or cross, except in a vertical or overhanging cliff.

When contour lines cross a stream, they form a “V” with the point of the V pointing upstream

Contour Interval The

difference in elevation between two side-by-side lines

Each map has a unique contour interval, so locate label on the map

Index Contours • Some contour lines

are marked by numbers representing their elevations.

• Practice!

• What is the elevation of the line that is left of the 100m index contour.

Depression Contour Lines

When the elevation is lower than the

surrounding area

there are “hachures” on the line

Contour Map ExampleOn this map, the vertical distance between each of the contour lines

is 10 feet.

1.Which hill is higher, hill A or hill B?

2.Which hill is steeper, hill A or hill B?

3.How many feet of elevation are there between contour lines?

4.How high is hill A? Hill B?

5.Are the contour lines closer on hill A or hill B?

Map Legends

A map legend explains what the symbols on a map represent

A means of showing the relationship between the size of an object indicated on a map and the actual size of the object on the surface of Earth.

DefinitionMap Scales

Fractional scale: - is a fixed ratio between linear measurements on the map and corresponding distances on the ground. Example: 1:62,500

Graphical scale: - is simply a line or bar drawn on the map and divided into units that represent ground distances.

Example:

Verbal scale: - is a convenient way of stating the relationship of map distance to ground distance.

Example: 1 inch equals 1 mile

1 0 1 2 3 4 Miles

Scale Types

Remote Sensing • The Electromagnetic Spectrum

The arrangement of electromagnetic radiation according to wavelengths

• Frequency refers to the # of waves that pass a particular point each second

Wave Characteristics

• Electromagnetic waves travel at the speed of 300,000 km/s in a vacuum“The Speed of Light”

Topex/Poseidon Satellites An emitter sends out-

going signal to the surface of the ocean

A receiver times the returning signal

Distance to ocean’s surface is calculated using the known speed of light and the return time.

Landsat Satellite

Receives reflected wavelengths of energy emitted by Earth’s surface, such as rivers and forests

GPS

A radio-navigation system of at least 24 satellites that allows its users to determine their exact location on Earth.

The receiver calculates the user’s precise lat/long by processing the signals emitted by multiple satellites.

Sea Beam

Used to map the ocean floor

Located on a ship rather than a satellite

Uses sonar which is the use of sound waves to detect and measure objects under water.