Maps and Map Skills
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
Compass
Title
Scale
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 Scale
Large Area = Small Scale
Large Scale
Small Scale
Small Area = Large Scale
Large 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
0
degrees, or parts of a circle. (41 )
• 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”)
0
• 41 10’10” Degrees 41
0
Minutes 10’
Seconds
10”
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.
0
• The equator’s latitude degree is 0 . There are 90
degrees between it and each of the poles.
• Area
between the equator and NP is “north” latitude
0
(22 N)
• Area
between the equator and SP is “south” latitude
0
(22 S)
• 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.
0
• Prime Meridian’s longitude degree is 0 .
0
0
• There are 180 of longitude east of the PM and 180
degrees west of it.
• Area east of the PM is known as “east” longitude.
0
(120 E)
• Area west of the PM is known as “west” longitude.
0
(120 W)
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
0
• At 180 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.
0
0
• Used for middle latitudes between 30 and 60 north
0
0
latitudes, and between 30 and 60 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.