EARTH SCIENCE
Geology, the Environment and the Universe
Chapter 2: Mapping Our World
CHAPTER
2
Table Of Contents
Section 2.1
Latitude and Longitude
Section 2.2
Types of Maps
Section 2.3
Remote Sensing
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SECTION
2.1
Latitude and Longitude
Essential Questions
• What is the difference between latitude and
longitude?
• Why is it important to give a city’s complete
coordinates when describing its location?
• Why are there different time zones from one
geographic area to the next?
SECTION
2.1
Latitude and Longitude
• Lines of latitude and longitude are used to locate
places on Earth.
Review Vocabulary
• time zone: a geographic region within which the
same standard time is used
SECTION
2.1
Latitude and Longitude
New Vocabulary
cartography
equator
latitude
longitude
prime meridian
International Date Line
SECTION
2.1
Latitude and Longitude
Latitude
• Maps are flat models of three-dimensional
objects.
• The science of mapmaking is called
cartography.
SECTION
2.1
Latitude and Longitude
Latitude
• The equator is an imaginary horizontal line
located at 0 latitude that circles Earth and
separates it into two equal halves.
• Latitude is the distance in degrees north or
south of the equator.
• Lines of latitude run parallel to the equator.
SECTION
2.1
Latitude and Longitude
Latitude
• The value in degrees of each line of latitude is
determined by measuring the imaginary angle
created between the equator, the center of
Earth, and the line of latitude.
SECTION
2.1
Latitude and Longitude
Longitude
• Longitude is the distance in degrees east or
west of the prime meridian.
• The prime meridian is an imaginary line that
represents 0 longitude.
• Lines of longitude, also called meridians, are
semicircles that extend vertically from pole to
pole.
SECTION
2.1
Latitude and Longitude
Longitude
• The degree value of each line of longitude is
determined by measuring the imaginary angle
between the prime meridian, the center of
Earth, and the line of longitude.
SECTION
Latitude and Longitude
2.1
Longitude
Using coordinates
• Both latitude and
longitude are needed to
locate precise positions
on Earth.
SECTION
2.1
Latitude and Longitude
Longitude
Time zones
• In most cases, each of Earth’s 24 time zones
corresponds roughly to a line of longitude and
represents a different hour. However, there are
some exceptions.
SECTION
2.1
Latitude and Longitude
Longitude
• The International Date Line, 180 meridian,
serves as the transition line for calendar days.
• Traveling west across the International Date Line
advances your calendar one day.
• Traveling east moves your calendar back one
day.
SECTION
2.1
Latitude and Longitude
Please click the image above to view the interactive table.
SECTION
2.1
Section Check
Lines of longitude are always parallel to
each other.
a. true
b. false
SECTION
Section Check
2.1
Where on Earth is 0 latitude?
a. the North Pole
b. the South Pole
c. the equator
d. the prime meridian
SECTION
2.2
Types of Maps
Essential Questions
• What are the different types of maps?
• Why are different maps used for different
purposes?
• How are gradients on a topographic map
calculated?
SECTION
2.2
Types of Maps
• Maps are flat projections that come in many
different forms.
Review Vocabulary
• parallel: extending in the same direction and
never intersecting
SECTION
2.2
Types of Maps
New Vocabulary
Mercator projection
conic projection
gnomonic projection
topographic map
contour line
contour interval
geologic map
map legend
map scale
SECTION
2.2
Types of Maps
Projections
• Cartographers use projections to make maps.
A map projection is made by transferring points
and lines on a globe’s surface onto a sheet of
paper.
SECTION
2.2
Types of Maps
Projections
• A Mercator projection is a map that has parallel
lines of latitude and longitude.
• It clearly indicates
direction in
straight lines.
• It is used for the
navigation of
ships and planes.
SECTION
2.2
Types of Maps
Projections
• A conic projection is made by
projecting points and lines from
a globe onto a cone.
• It has a high degree of accuracy
for limited areas.
• It is used to make road maps
and weather maps.
SECTION
2.2
Types of Maps
Projections
• A gnomonic projection is made by projecting
points and lines from a globe onto a piece of
paper that touches the globe at a single point.
• It is most useful for planning
long travel routes.
• It is used for navigation.
SECTION
2.2
Types of Maps
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SECTION
2.2
Types of Maps
Topographic Maps
• Topographic maps are detailed maps that use
contour lines, symbols, and colors to represent
changes in elevation and features on Earth’s
surface.
SECTION
2.2
Types of Maps
Topographic Maps
• A contour line connects points of equal
elevation on a topographic map.
• The difference in elevation between two side-byside contour lines is called the contour interval.
SECTION
2.2
Types of Maps
Topographic Maps
• Index contours are contour
lines labeled with a number
that indicates the elevation.
• Depression contour lines
have hachures, or short lines
at right angles to the contour
line, to indicate the direction
of elevation change.
SECTION
2.2
Types of Maps
Geologic Maps
• A geologic map is used to
show the distribution,
arrangement, and type of
rocks located below the
soil. It may also show
geologic features such as
fault lines.
SECTION
2.2
Types of Maps
Please click the image above to view the video.
SECTION
2.2
Types of Maps
Topographic Maps
Three-dimensional maps
• When scientists need to visualize Earth threedimensionally, they often rely on computers to
digitize features such as rivers, mountains,
valleys, and hills.
SECTION
2.2
Types of Maps
Map Legends
• A map legend explains
what the symbols on a
map represent.
SECTION
Types of Maps
2.2
Map Scales
• A map scale is the ratio between distances on a
map and actual distances on the surface of Earth.
Verbal Scales
• When referring to maps, verbal scales are
statements used to express distance.
SECTION
Types of Maps
2.2
Map Scales
Graphic scales
• Graphic scales consist of a line that represents
a certain distance. These are the most common
types of map scale.
Fractional scales
• Fractional scales express distance as a ratio
between two units of the same type.
SECTION
2.2
Section Check
Why do some time zone boundaries
have an irregular shape?
SECTION
2.2
Section Check
Answer: Some time zone boundaries were
drawn to have irregular shapes for convenience.
To avoid confusion, some boundaries were
adjusted so that they did not divide a particular
town or city.
SECTION
Section Check
2.2
Topographic contours on a map can
never cross.
a. true
b. false
SECTION
Section Check
2.2
Maps are produced at various scales. At
which fractional scale does one unit on
the map represent the largest distance
on the ground?
a. 1:20,000
b. 1:40,000
c. 1:63,500
d. 1:100,000
SECTION
2.2
Section Check
A geologic map has many different
colors. What do the colors
represent?
a. different surface temperatures
b. different types of rock formations
c. different geologic terrain
d. different elevations
SECTION
2.3
Remote Sensing
Essential Questions
• What are some of the different types of remote
sensing?
• How are satellites and sonar used to map Earth’s
surface and its oceans?
• What is the Global Positioning System and how
does it work?
SECTION
2.3
Remote Sensing
• New technologies have changed the
appearance and use of maps.
Review Vocabulary
• satellite: natural or human-made object that
orbits Earth, the Moon, or another celestial body
SECTION
2.3
Remote Sensing
New Vocabulary
remote sensing
Landsat satellite
sonar
Global Positioning System
Geographic Information
System
SECTION
2.3
Remote Sensing
Landsat Satellite
• The process of gathering data about Earth using
instruments mounted on satellites, airplanes, or
ships is called remote sensing.
• Landsat satellites record reflected wavelengths
of visible light and infrared radiation from Earth’s
surface, and then computers convert the
information into digital images.
SECTION
2.3
Remote Sensing
Landsat Satellite
• Landsat data are used to study pollution, the
movements of Earth’s plates, and the melting of
glaciers and ice caps.
SECTION
2.3
Remote Sensing
OSTM/Jason-2 Satellite
• One satellite that uses radar to measure and map
sea surface height is the OSTM/Jason-2 satellite.
• Radar uses high-frequency signals that are
transmitted from the satellite to the surface of the
ocean. A receiving device then picks up the
returning echo as it is reflected off the water.
SECTION
2.3
Remote Sensing
OSTM/Jason-2 Satellite
• Using OSTM/Jason-2 data, scientists are able to
estimate global sea levels with an accuracy of just
a few millimeters.
• Scientists can use this data combined with other
existing data to create maps of ocean-floor
features.
SECTION
2.3
Remote Sensing
SeaBeam
• Sonar is the use of sound waves to detect and
measure objects underwater.
• SeaBeam technology uses sonar to map the
ocean floor from a ship.
SECTION
2.3
Remote Sensing
SeaBeam
• A sound wave is sent from a ship toward the
ocean floor. A receiving device picks up the
returning echo when it bounces off the seafloor.
• A computer calculates the distance from the ship
to the ocean floor using the speed of sound in
water and the time it takes for the sound to be
reflected.
SECTION
2.3
Remote Sensing
SeaBeam
• SeaBeam technology is used by fishing fleets,
deep-sea drilling operations, oceanographers,
volcanologists, and archaeologists.
SECTION
2.3
Remote Sensing
The Global Positioning System
• The Global Positioning System (GPS) is a
satellite navigation system that allows users to
locate their approximate position on Earth.
• These satellites can also relay information to a
GPS receiver about elevation, direction of
movement, and speed.
SECTION
2.3
Remote Sensing
The Global Positioning System
Uses for GPS technology
• GPS technology is used extensively in
navigation by airplanes and ships.
• GPS receivers also help people in everyday
life to find a destination or determine their
current location.
SECTION
2.3
Remote Sensing
The Geographic Information System
• The Geographic Information System (GIS)
uses a worldwide database to create layers, or
“themes,” of information that can be placed one
on top of the other to create a comprehensive
map.
SECTION
2.3
Remote Sensing
The Geographic Information System
• GIS map layers remain linked to the original
information, so if the original information changes,
the GIS layers also change. The result is a map
that is always up-to-date.
SECTION
2.3
Remote Sensing
Visualizing GPS Satellites
• GPS receivers detect signals from the 24 GPS
satellites orbiting Earth. Using signals from at
least three satellites, the receiver can calculate
location within 10 m.
SECTION
2.3
Remote Sensing
Please click the image above to view the video.
SECTION
Section Check
2.3
At least how many Global Positioning
System satellites are needed to fix a
location?
a. two
b. three
c. four
d. five
SECTION
2.3
Section Check
A radar signal is sent from a satellite to
the ocean’s surface. What information
must be known to calculate distance
from the return echo?
a. speed and time of the echo
b. wavelength and time of the echo
c. power and speed of the echo
d. time and power of the echo
SECTION
2.3
Section Check
What advantages does remote sensing
have over other methods of data
acquisition?
Answer: Remote sensing allows data to be
acquired from a large region quickly, and the data
can be updated frequently. Remote sensing can
also be used to acquire data from remote
locations that would be difficult to observe directly.
CHAPTER
Mapping Our World
2
Resources
Earth Science Online
Study Guide
Chapter Assessment Questions
Standardized Test Practice
Click on a hyperlink to view the corresponding feature.
SECTION
Latitude and Longitude
2.1
Study Guide
• Lines of latitude and longitude are used to locate
places on Earth.
• Latitude lines run parallel to the equator.
• Longitude lines run from pole to pole.
SECTION
Latitude and Longitude
2.1
Study Guide
• Both latitude and longitude lines are necessary
to locate exact places on Earth.
• Earth is divided into 24 time zones, each 15
wide, that help regulate daylight hours across
the world.
SECTION
Types of Maps
2.2
Study Guide
• Maps are flat projections that come in many
different forms.
• Different types of projections are used for
different purposes.
• Geologic maps help Earth scientists study
patterns in subsurface geologic formations.
SECTION
Types of Maps
2.2
Study Guide
• Maps often contain a map legend that allows
the user to determine what the symbols on the
map signify.
• The map scale allows the user to determine
the ratio between distances on a map and
actual distances on the surface of Earth.
SECTION
Remote Sensing
2.3
Study Guide
• New technologies have changed the appearance
and use of maps.
• Remote sensing is an important part of modern
cartography.
• Satellites are used to gather data about features
of Earth’s surface.
SECTION
Remote Sensing
2.3
Study Guide
• Sonar is also used to gather data about
features of Earth’s surface.
• GPS is a navigational tool that is now used
in many everyday items.
CHAPTER
2
Mapping Our World
Chapter Assessment
The contours at a location on a topographic
map are very close together. What does this
suggest about the land surface?
a. The land has a high elevation.
b. The land has a low elevation.
c. The land has a steep slope.
d. The land has a gentle slope.
CHAPTER
2
Mapping Our World
Chapter Assessment
How does the time change when passing from
east to west across the International Date
Line?
a. It moves ahead one day.
b. It moves back one day.
c. It moves ahead one hour.
d. It moves back one hour.
CHAPTER
2
Mapping Our World
Chapter Assessment
At which latitude is the distance between
meridians of longitude smallest?
a. 30 N
b. 50 S
c. 80 N
d. 75 S
CHAPTER
2
Mapping Our World
Chapter Assessment
Which representation of Earth is made by
projecting points and lines from a globe onto
paper that touches the globe at a single point?
a. Mercator projection
b. gnomonic projection
c. geologic map
d. conic projection
CHAPTER
2
Mapping Our World
Chapter Assessment
How are maps that consist of many layers of
data made?
Answer: These maps are made by using the
Geographic Information System. Data from
remote sensing or other sources are fed to a
computer. The digitized data then can be read,
displayed, and analyzed as separate layers or as
superimposed layers.
CHAPTER
2
Mapping Our World
Standardized Test Practice
When it is 10:00 P.M. in New York City, where on
Earth is the time 5:00 A.M.?
a. five time zones to the east
b. five time zones to the west
c. seven time zones to the east
d. seven time zones to the west
CHAPTER
2
Mapping Our World
Standardized Test Practice
A truck driver is on a north-south highway.
About how far must the driver travel to cover
one degree of latitude?
a. 42 kilometers
b. 111 kilometers
c. 530 kilometers
d. 725 kilometers
CHAPTER
2
Mapping Our World
Standardized Test Practice
A group of hikers wants to plan a safe route to
the top of a mountain. Which type of resource
would be most useful for this purpose?
a. gnomonic projection
b. Mercator projection
c. geologic map
d. topographic map
CHAPTER
2
Mapping Our World
Standardized Test Practice
The Global Positioning System has many
applications. Describe three different uses for
this system.
CHAPTER
2
Mapping Our World
Standardized Test Practice
Possible answer: The Global Positioning System
is used for the navigation of planes and ships. It is
used by scientists to measure land elevation and
track movement. Everyday uses of the technology
include handheld or mounted receivers that can
direct a person to a specific address or location.
CHAPTER
2
Mapping Our World
Standardized Test Practice
A Mercator projection of the world is displayed
at the front of a classroom. How is the
projection misleading?
Answer: On a Mercator projection, meridians
are shown as parallel lines. As a result, the
size of landmasses located near the poles is
greatly exaggerated.