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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