Understanding Maps (cont.)
Maps have two features to help you read
and understand the map: a series of
symbols called a map legend, and a
ratio, which establishes the map scale.
Understanding Maps (cont.)
A map legend is a key that lists all the
symbols used on the map that help you
interpret the symbols.
map legend
Understanding Maps (cont.)
legend
Science Use part of a map that
explains the map symbols
Common Use a story coming
down from the past
Understanding Maps (cont.)
Model builders typically use scale to
make the model measurements accurate
to the measurements of the real object.
Understanding Maps (cont.)
A map scale is the relationship between
a distance on the map and the actual
distance on the ground.
Reading Maps
• Long ago, mapmakers created a grid
system of two sets of imaginary lines,
called longitude and latitude, which
encircle Earth.
• Mapmakers started the grid system
with a vertical line that circled Earth
and passes through the North Pole and
the South Pole.
Reading Maps (cont.)
• The half of this vertical circle that
passes through Greenwich, England, is
known as the prime meridian.
• The other half of this vertical circle is
the 180° meridian.
Reading Maps (cont.)
Similar circles are drawn at every degree
east and west of the prime meridian.
These lines are referred to as lines of
longitude.
longitude
from Latin longitudo, means
“length”
Reading Maps (cont.)
• A location’s longitude is the distance
in degrees east or west of the prime
meridian.
• The prime meridian and the 180°
meridian divide Earth into the Eastern
Hemisphere and the Western
Hemisphere.
Reading Maps (cont.)
The lines east of the
prime meridian are
called east
longitude, and the
lines west of the
prime meridian are
called west
longitude.
Reading Maps (cont.)
• Mapmakers also drew horizontal lines
from east to west around Earth. The
equator is the center and largest circle
of these horizontal lines.
• The equator divides
Earth into the
Northern Hemisphere
and the Southern
Hemisphere.
Reading Maps (cont.)
• Parallel circles are drawn at every
degree north and south of the equator.
These lines are referred to as lines of
latitude.
• The North Pole and the South Pole are
each indicated by a dot at 90° N and
90° S.
• A location’s latitude is the distance in
degrees north or south of the equator.
Reading Maps (cont.)
Together, longitude and latitude are used
to pinpoint a location on Earth.
Reading Maps (cont.)
What relationship do lines of
longitude and lines of latitude
have?
Plotting Locations
• Any location on Earth can be described
by the intersection of the closest line of
latitude and the closest line of
longitude.
• Because longitude and latitude lines
are far apart, we divide each degree
into 60 minutes (') and each minute into
60 seconds (") to help pinpoint
locations.
Plotting Locations (cont.)
How do latitude and longitude
describe a location on Earth?
• Finding locations on a map or a globe
can be done accurately by using grid
lines called longitude and latitude.
What do model builders use to
make model measurements
accurate to the measurements of
the real object?
A. size
C. scale
B. weight
D. legend
Which of these terms refers to the
distance in degrees north or
south of the equator?
A. longitude
B. latitude
C. scale
D. ratio
Types of Maps
A topographic map shows the detailed
shapes of Earth’s surface, along with its
natural and human-made features.
topography
from Greek topos, means “place”;
and graphein, means “to write”
Types of Maps (cont.)
A topographic map helps give you a
picture of what the landscape looks like
without seeing it.
Robert Glusic/Getty Images
Types of Maps (cont.)
• The height above sea level of any point
on Earth’s surface is its elevation.
• The difference in elevation between the
highest and lowest point in an area is
called relief.
Types of Maps (cont.)
Contour lines are lines on a topographic
map that connect points of equal
elevation.
Types of Maps (cont.)
• The elevation difference between
contours that are next to each other is
called the contour interval.
• Slope is a measure of the steepness of
the land.
Types of Maps (cont.)
• If the contours are spaced far apart,
the slope is gradual or flat, but if the
contours are close together, the slope
is steep.
• The information contour lines provide
on a topographic map can be used to
draw an accurate profile of the
topography.
Types of Maps (cont.)
What can you learn about the
features at Earth’s surface
from studying contour lines?
Making Maps Today (cont.)
The Global Positioning
System (GPS) is a
group of 24 satellites
orbiting Earth used
for navigation.
Making Maps Today (cont.)
• The signals relayed by GPS satellites
are used to calculate the distance to the
satellite based on the average time of
the signal.
• GPS is used by mapmakers to
accurately locate reference points.
Making Maps Today (cont.)
• Geographic Information Systems (GIS)
are computerized information systems
used to store and analyze map data.
• GIS creates different map layers of the
same location using database view,
map view, and model view.
• Topographic maps use contour lines
to help describe the elevation and
relief of the surface of Earth at that
spot.
• Geologic maps are useful in
determining the kind of rocks, the
age of rocks, and the formations they
are found in for an area.
What is the height above sea level
of any point on Earth’s surface
called?
A. slope
B. contour interval
C. elevation
D. cross section
Which term refers to the process
of collecting information about an
area without coming into physical
contact with it?
A. navigation
B. mapping
C. modeling
D. remote sensing
Which of these refers to the
distance in degrees east or west
of the prime meridian?
A. latitude
B. longitude
C. scale
D. time zone
What is the difference in elevation
between the highest and lowest
point in an area is called?
A. slope
B. topography
C. relief
D. elevation
What feature of a topographic
map connects points of equal
elevation?
A. contour lines
B. cross sections
C. contour intervals
D. geologic maps
Which term refers to the elevation
difference between contours that
are next to each other?
A. slope
B. contour interval
C. steepness
D. relief
Which term refers to the key that
lists all the symbols used on the
map to help you interpret the
symbols?
A. map key
B. map scale
C. profile view
D. map legend
What is the center line of
latitude?
A. prime meridian
B. longitude
C. equator
D. legend
Which term is a measure of the
steepness of land?
A. contour
B. slope
C. elevation
D. topography
Which term refers to the elevation
difference between contours that
are next to each other?
A. the Geographic Information
System
B. sonar
C. the Global Positioning System
D. the contour interval