Maps and Map Skills

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Kinds of Maps• General Reference Maps

• Provide the reader general information about an area or place.

• Thematic Maps• Provide more specific information about

an area or place than general reference maps.

General reference

Thematic Map

• Maps are important tools for geographers.

• A globe is a better model of Earth than a map, but a globe has disadvantages that a map does not have

Reading Maps• Map Parts

• Title• Legend or Key• Grid System• Direction• Scale

• Map orientation – This has to do with direction

Scale

Title

Compass

Large Scale and Small Scale Maps

• A large-scale map shows a small area such as a neighborhood street in great detail.

• A small-scale map shows a large area such as a country or a continent in comparatively lesser detail.

Small Area = Large ScaleLarge Area = Small Scale

Large ScaleSmall Scale

Small Area = Large ScaleLarge Area = Small Scale

Compass• Is used to orient a map toward north

Latitude and Longitude

• Latitude • The set of lines crossing the Earth’s surface horizontally,

Circling east and west. • Each line of latitude is always an equal distance from the

next.• They are also known as parallels. All latitude lines are

parallel to each other.

• Longitude• A set of lines that run vertically along Earth’s

surface from the North Pole to the South Pole

Global Grid• When lines of latitude and longitude cross a grid is

formed. The grid is used to located certain places on earth

• Each line has an Identifying number called degrees, or parts of a circle. (410 )

• Degrees, can be further divided into minutes, or parts of a degree. There are 60 minutes, or parts of a degree. (10’)

• Minutes can be divided into even smaller parts called seconds. There are 60 seconds in each minute. (10”)

• 41010’10” 410

10’

10”

Degrees

Minutes

Seconds

Direction

• The other part needed to locate places on Earth is direction.• Cardinal directions are: north, south, east, and

west.• Intermediate directions are: northeast,

southeast, northwest, and southwest. They are located midway between the cardinal directions.

Using Latitude & Longitude to Locate Places

• Lines of latitude are numbered based on how far north or south they are from an imaginary line called the equator

• This line circles the Earth exactly halfway between the NP and SP.

• The equator’s latitude degree is 00. There are 90 degrees between it and each of the poles.• Area between the equator and NP is “north” latitude

(220N)

• Area between the equator and SP is “south” latitude (22

0S)

• Lines of longitude are numbered based on how far east or west they are from another imaginary line.

• This line is called the Prime Meridian.• Prime Meridian’s longitude degree is 00. • There are 1800 of longitude east of the PM and 1800

degrees west of it.• Area east of the PM is known as “east” longitude.

(1200E)

• Area west of the PM is known as “west” longitude. (120

0W)

Prime Meridian & International Date Line

• The prime meridian does not circle the globe as the equator does.

• The PM runs from the NP to SP• At 1800 on the other side of the globe the

meridian is called the international date line.

Hemispheres• The earth can be divided into halves. Each of these

halves is called a hemisphere.

Hemispheres at the Equator • The ½ north of the equator

is called the northern hemisphere

• The ½ south of the equator is called the southern hemisphere

Hemispheres at Prime Meridian and International

Date Line• Earth can also be divided into hemispheres

at the circle formed by the prime meridian and International date line

• The ½ east of the prime meridian is called the eastern hemisphere.

• The ½ west of the prime meridian is called the western hemisphere.

Making Maps• Gathering Information• Problem of Distortion• Map Properties• Map Projections• Cartographers (Mapmakers)

Gathering Information

• Surveying• Aerial Photography (Air Planes)• Remote Sensing (Satellites)

Problem of Distortion• Features are stretched to put

Earth’s information onto a map.

Map Properties• No map can have all of the properties at once

• Equal areas• Conformality• Consistent Scale• True-Compass Directions

• Equal areas• Places shown have the same proportions as they do

on Earth. • Example: Greenland 1/8 land area of S. America

• Conformality• Having correct shapes.• Shows true shapes.• Can show larger areas as closely as possible to

their true shapes

• Consistent Scale• Uses the same scale for all parts of the map.• Shows the true distances between places on Earth• In most Cases maps showing large areas cannot be

consistent-scale maps.

•True-Compass Direction• Parallels and meridians

appear as straight lines.• By following these lines

you will be following the cardinal directions of N,S,E,&W.

• Straight line between two points on map determines exact directions and set course. (Navigators use these maps)

Map Projections• Cylindrical Projections• Conic Projections• Flat Plane Projections• Gnomonic Projection• Robinson Projection• Goode’s Interrupted

Cylindrical Projections• Straight lines of latitude and Longitude are

Perpendicular• Little distortion near the equator• Best Known:

• Mercator – • conformal and true-compass direction map, but

distortion near poles makes size of land and water areas inaccurate. Land shapes correct – areas distorted – valuable to navigator

Conic Projections• Cannot map the entire world.• Used for middle latitudes between 300 and 600 north

latitudes, and between 300 and 600 south latitudes• Best Known:

• Lambert Conformal Conical • Important because it shows the true shapes of

areas.• Albers Equal Area Conical

• Consistent scale and is used when the size of land and water areas must be accurate. (military and engineering maps)

Flat Plane Projections• Used to map areas of the North and South

poles. Areas near that point show little distortion

• Farther away from the point the greater the distortion of area, shape, and scale.

• Shows no more that ½ of the Earth at one time.

• Also called Azimuthal Projection

Gnomonic Projection• Circles of latitude lines and straight longitude

lines form a wheel-like pattern.• Especially useful to navigators because the

shortest distance between two places on the map is found by drawing a straight line between them {this line is actually a part of a great circle – any imaginary line that circles Earth and divides it into 2 equal parts

• Navigators use these along with true-compass direction maps to make their travel plans.

Robinson Projection• Equal areas – shown with high degree of

accuracy• Conformal except near edges of map where

distortion increases• Valuable for showing entire world.

Goode’s Interrupted• High degree of accuracy in area and shape• Distorted direction and scale.• Valuable for showing Land masses.

Points to Remember• The projection one chooses to use depends

on the information one wants.• All Maps are projections – they transfer

Earth’s features from the globe to a flat surface (map).

• When large areas of Earth are mapped, distortion is more serious.

• When mapping small areas like cities, distortion is not usually evident.