Unit 2: Map Skills(Chapter 3)

On a piece of paper, draw a map from the high school (point A) to Kendall 10 Theater (point B). Please label

anything that would help a person to get from point A to point B.

MAPS

• A model (representation) of the Earth• shows all or part of the round earth• a way to share knowledge and information about the

world• flat, printed documents, 2-D• made by cartographers (mapmakers) and

mathematicians• shown in different map projections

(different ways maps are drawn)

Map Projections

• On-going controversy has been which projection accurately depicts the continents

• Because Earth is round, there is always some distortion on any flat map.

• A cartographer has to choose which projection best shows features(without distortion)

Map ProjectionsMaps can have true (accurate) ….

• Directions• Distances• Areas• Shapes• HOWEVER, a map cannot have ALL of the

above correct at the same time!• Some map projections are better at some

features than others.

Historically…

• Land ownership,

• political boundaries

• Travel: the “age of explorations”

How have maps been used in the past and in

the present?

Map Projections

• At least 100 different types• Maps are used for

– Political– Travel– Commerce– Satellites

• We will learn the basics

Map Projections

Three Types of Map Projections:

1. Mercator2. Gnomonic3. Polyconic

Mercator Projection• One continuous map• As if a piece of paper was wrapped around the planet• Shows whole world, but NOT extreme polar region

Mercator Projection

Mercator Projection

• Advantages– Directions are true– Nice, rectangular shaped map– Accurate near the equator– Latitude and longitude lines are

straight and parallel

Mercator Projection• Distorts areas near poles

• On a Mercator projection, Greenland appears stretched out, exaggerated in size

• About 500% larger than actual size.– (Greenland is in fact about the same size as Mexico.)

• Antarctica appears so large it is seemingly set for world domination on this scale!– (except it doesn’t have an army)

Gnomonic Projection

• A.K.A. planar projection• Circular in shape• Uses:

– Planning ocean and air voyages– Depicting polar regions

Latitude lines are circleslongitude lines radiate from the center

Gnomonic Projection

• Advantages– Accurately shows the shortest

distance between two points.– Accurate for polar regions.

• Disadvantages– Distorts landmass shapes away from

the center point of the circle.

Polyconic Projection

• Made as if a cone of paper was wrapped around Earth

Polyconic Projection

• Used in Atlas

• Mapping large areas of land that fall in the middle latitudes

• Longitude meridians are straight,

latitude lines “fan out”

Polyconic Projection

• Advantages– Reasonably Accurate

• Directions• Shapes• Areas

• Disadvantages– Latitude and longitude are curved slightly– Distortion increase away from standard

parallels– Oddly shaped map

Globe Projection

• Advantages: – 3D– Shows true: Direction,

Distances, Areas, Shapes

• Disadvantages:– Expensive– Bulky to carry in your glove compartment

*The world's largest globe, with a circumference of 131 feet

Map ProjectionsQuiz Time!

1. A country in the tropics should use a…

2. A country in the temperate zone (like U.S.A.) should use a…

3. A polar region should use a …

a. cylindrical (Mercator)

b. planar (gnomonic)

c. conical (polyconical)

Synopsis of Map Projections

– Mercators are true at the equator and distortion

increases toward the poles– Conics are true along some parallel somewhere

between the equator and a pole and distortion increases away from this standard

– Gnomonics are true only at their center point, but generally distortion is worst at the edge of the map

Hemispheres

What hemispheres do we live in?

Latitude and Longitude

• To find an exact place on a map or on Earth, you need crossing lines that create an intersection (place where two lines meet)

• coordinates (numbers indicate a specific point) • grid system

– known as the latitude and longitude grid

Latitude and Longitude

• Places can be exactly located using coordinates and plotting them on a “grid”

• latitude and longitude

• Measured in degrees, minutes and seconds

(360° 60' 60")

Horizontal like rungs on a ladder

Long, tall vertical lines

Latitude• Also called “parallels”• horizontal “rings” that circle around the globe.• They are equal distances apart.

1° degree of latitude = 65 miles or 111 km

• Go from 0° to 90° north (North Pole)

0° to 90° south (South Pole)

Longitude• Also called meridians.• Meridians meet at the poles.• They are measured from zero or prime meridian.• Lines are measured going

east from 0° to 180° west from 0° to 180°

• Distances between longitude lines are NOT equal– At equator, 1o = 111 km (65 miles)– At 45°, 1o = 79 km ( 49 miles) – At the North pole, 1o = ZERO km!

The Prime Meridian• Located at the Royal Observatory in

Greenwich, England

• 0 degrees longitude

• Runs through countries such as United Kingdom, France, Spain, Algeria

Where on earth is 0° latitude and 0° longitude located?

In the Atlantic Ocean, about 360 miles south of Ghana

Map Scale

• Maps are not drawn to the same scale as the world • There has to be an amount of reduction in size• Ratio of the distance between two points on the

map compared to the actual ground distanceMap Scale = Map Distance

Earth Distance

map distance : Earth (ground) distance

3 types of map scales

3 types of map scales

• 1: 24000 map scale …

1 inch on the map = 24,000 inches on the ground! …

24,000 inches = 2000 feet

3 types of map scales

• 1:100,000 scale

1 cm = 100,000 cm …

or 1 kilometer on the surface

(about 0.62 miles)

A map of the world has a scale of1: 46,000,000 !!!!

U.S.A. Map would have a scale of1: 5,000,000

• A map of Illinois

would have a scale of

1: 500,000

A map of Kendall County would have a scale of1: 62,500

Oswego town map would have a scale of1: 1000

Large –scale map

• Shows a small area with a lot of detail.

• Good for urban areas, towns, streets or hiking.

• Example: 1:10,000

• Large enough to see details

Small-scale map

• Shows a LARGE area with very little detail.

• Good for world maps or large regions such as North America.

• Example: 1:1,000,000

• Too small to see details