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Topographic Maps
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To read a map, you must understand the symbols and be able
to find directions and calculate distances.
MAP LEGEND:
-The area located on a map that
shows symbols and
features needed to read the
map properly.
-Contains useful information such
as map scale, distance
scale, North arrow, highway
and road classifications.
-Is generally located at the bottom
of the map or outside
the map boundaries.
Map Legends
• A Map Scale is the ratio between distances on a map and actual distances on the surface of Earth.
Map Scales
• When using a map, you need to know how
to measure distances.
Types of Maps
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• Verbal Scale:
– one inch equals one mile (1” = 1 mi.)
• Graphic Scale:
– bar scale that graphically shows relationship
between map distance and actual distance
• Fractional Scale :
– a ratio (1:50,000) or a fraction
5 mile
0 5
- Maps can have 3 types of scales to show the
relationship between distance as shown on a map and
the actual distance on the earth’s surface.
Map Scales
Topographic Maps
• Topographic maps are
detailed maps showing
the elevations of hills
and valleys of an area.
Types of Maps
• Topographic maps use lines, symbols, and colors to represent changes in elevation and features on Earth’s surface.
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---------HICKING TRAIL
SPOT ELEVATIONS
CEMETARY
TOPOGRAPHIC SYMBOLS
MAN MADE OBJECTS
SINGLE TRACK RR
BRIDGE
BM 280
MINECHURCH
BUILDING SCHOOL
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IMPROVED ROAD
MEDIUM DUTY
UNIMPROVED ROAD
HEAVY DUTY
TOPOGRAPHIC SYMBOLS
MAN MADE OBJECTS
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STREAM INTERMITTENT STREAM
INTERMITTENT LAKE / PONDLAKE / POND
TOPOGRAPHIC SYMBOLS
DRAINAGE
How to Read
Topographic Maps
Contour Lines
Types of Maps
– Elevation on a topographic map is represented by a contour line.
– A Contour Line connects points of equal elevation.
– Elevation refers to the distance of a location above or below sea level.
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CONTOUR LINES (BROWN)
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Index Contours
Types of Maps
– Index contours are contour lines that are marked by numbers representing their elevations.
– If a contour interval on a map is 5 m, you can determine the elevations represented by other lines around the index contour by adding or subtracting 5 m from the elevation indicated on the index contour.
How to Read
Topographic Maps
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CONTOUR LINES (BROWN)
Index
Contours
Contour Intervals
Types of Maps
– Topographic maps use contour lines to show changes in elevation.
– The Contour Interval is the difference in elevation between two side-by-side contour lines.
– The contour interval is dependent on the terrain.
How to Read
Topographic Maps
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READING CONTOUR LINES
How high is
this point?
What is the
Elev of the
Dam?
840 ft
700 ft
What is the stream
gradient between
both lakes?
Locate The
Following
Topographic
Features On You Map
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HILLTOP
ON THE MAP ON THE GROUND
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SADDLE
ON THE MAP ON THE GROUND
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VALLEY
ON THE MAP ON THE GROUND
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RIDGE
ON THE GROUND ON THE MAP
RIDGE
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The Global Positioning System
• The Global Positioning System, or GPS, is a
radio-navigation system of at least 24 satellites
that allows its users to determine their exact
position on Earth.
Remote Sensing
• Each satellite orbits Earth and transmits high-frequency microwaves that contain information about the satellite’s position and the time of transmission.
• A GPS receiver calculates the user’s precise latitude and longitude by processing the signals emitted by multiple satellites.
Chapter Assessment
Chapter Assessment
1. Match the following terms with their definitions.
___ contour interval
___ map legend
___ map scale
A. the difference in elevation between two side-by-side contour lines
B. a diagram that explains what the symbols on a map represent
C. the ratio between distances on a map and actual distances on the surface of Earth
A
B
C
3. What does it mean if a map says
“Scale 1:100 000”?
This fractional scale means that one unit on the map represents 100 000 units on Earth’s surface. For example, one inch on the map would equal 100 000 inches on Earth’s surface.
Chapter Assessment
3. How does the Global Positioning System
work?
Each Global Positioning Satellite orbits Earth and transmits high frequency microwaves that contain information about the satellite’s position and the time of transmission. The orbits of the satellites are arranged so that signals from several satellites can be picked up at any given moment by a GPS user equipped with a receiver. The receiver calculates the user’s precise latitude and longitude by processing the signals emitted by multiple satellites.
Chapter Assessment
4. Which of the following is NOT true about
lines of latitude.
a. They are parallel to each other.
b. They connect the north and south poles.
c. They are either referenced as north or
south.
d. Latitude is measured from 0º to 90º.
Lines of latitude are parallel to the equator. The equator is 0º and each pole is 90º. Lines of longitude connect the north and south pole.
Chapter Assessment
5. What is the reference point for lines of
longitude?
a. the equator
b. the International Date Line
c. the prime meridian
d. Earth’s center
The prime meridian, which runs through Greenwich, England, is 0º longitude. The equator is the reference for latitude. The International Date Line, which is 180º E or W, is opposite the prime meridian. Earth’s center is used to find the line of latitude but it is not a reference point.
Chapter Assessment
6. What represents equal elevation on a
topographical map?
a. Legend c. Saddle
b. Map scale d. Contour lines
Great circles represent the shortest distance between two points on a sphere. A map scale is the ratio between distances on a map and actual distances on the surface of Earth.
Chapter Assessment
7. What is the distance between one
degree of longitude?
a. 111 km
b. 48 km
c. 2 km
d. all of the above
Remember the lines of longitude are not parallel. The distance between lines of longitude ranges from 111 km to essentially the distance covered by a point at the poles.
Chapter Assessment
8. If it is 6:00 P.M. on July 4 in Los Angeles,
California, what day and time is it in
Tokyo, Japan?
It would be 10:00 A.M. on July 5.
Chapter Assessment
9. Identify whether the following statements are true or false.
______ Contour lines can cross each other.
______ The United States has six time zones.
______ If you travel east across the International Date
Line, you would move your calendar back
one day.
False
True
True
Chapter Assessment
End of Section 2