LAB MODULE 2: THE GEOGRAPHER’S TOOLS
Note: Please refer to the GETTING STARTED lab module to learn tips on how to set
up and maneuver through the Google Earth ( ) component of this lab.
KEY TERMS
The following is a list of important words and concepts used in this lab module:
Absolute location Geographic Information System (GIS)
Remote sensing
Aerial photographs Land Use/Land Cover Satellite images (Landsat)
Cartographer Larger scale map Scale
Contours, contour
lines
Latitude Slope
Contour interval (CI) Longitude Small scale map
Coordinate systems Map scale (Scale) Spatial analysis
False color composite Map types Thematic maps
Geospatial
technologies
Relative location
LAB MODULE LEARNING OBJECTIVES
After successfully completing this lab module, you should be able to:
Use latitude and longitude to find an absolute location
Explain the difference between large and small scale maps Calculate map scale Identify and describe the three types of maps
Interpret contour maps Identify changes in land use and land cover using remotely sensed images
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INTRODUCTION
This lab module examines fundamental concepts and tools geographers use to
study the Earth. Topics include latitude and longitude, absolute and relative
location, geospatial technologies, map types and scale. While these topics may
seem disparate, you will learn how they are inherently related.
The modules start with four opening topics, or vignettes, found in the
accompanying Google Earth file. These vignettes introduce basic concepts related to
geospatial tools and technologies. Some of the vignettes have animations, videos,
or short articles that will provide another perspective or visual explanation for the
topic at hand. After reading each vignette and associated links, answer the
following questions. Please note that some components of this lab may take a while
to download or open, especially if you have a slow internet connection.
Expand GEOGRAPHER’S TOOLS, and then expand the INTRODUCTION folder.
Double-click Topic 1: Tools for Geography.
Read Topic 1: Tools for Geography.
Question 1: According to the article, what are three geographic technologies
geographers use to study the Earth?
A. GIS, GPS, and compasses
B. GPS, remote sensing, and GIS
C. GIS, AutoCAD, and remote sensing
D. GPS, Glovis, and GIS
Read Topic 2: Maps.
Question 2: In what state was the first topographic map (relief map using
contour lines) issued in the United States?
A. Delaware
B. Louisiana
C. Maryland
D. Mississippi
Read Topic 3: Coordinate Systems and Location.
Question 3: What continent is found at grid cell 35N?
A. The continent of Africa
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B. The continent of Australia
C. The continent of Europe
D. The continent of South America
Read Topic 4: Geospatial Technologies.
Question 4: Looking at the map layers above, which layers would be most
likely acquired through the use of radar and satellites?
A. States and cities
B. Countries and Territories
C. Background
D. Radar and Satellite
Collapse and uncheck INTRODUCTION.
GLOBAL PERSPECTIVE
Latitude and Longitude form a grid on the Earth’s surface, enabling us to determine
an absolute location for any given place or phenomenon.
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Expand GLOBAL PERSPECTIVE.
Turn on the latitude and longitude grid by selecting View > Grid, or by using
the keyboard shortcut CTRL + L. Mac users click + L.
Lines of latitude, or parallels, divide the globe at the Equator, and run parallel in
both the Northern and Southern Hemispheres (Figure 1). Locations in the Northern
Hemisphere are denoted with an N (or a positive number), while locations in the
Southern Hemisphere are denoted with an S (or a negative number). The parallel at
the Equator is 0°N or 0°S, and increases to 90°N (or +90) at the North Pole, and
90°S (or -90) at the South Pole.
Latitude (parallels)
Longitude (meridians)
Figure 1. Lines of latitude (parallels) and longitude (meridians) (Arbogast)
Double-click and select Prime Meridian.
Lines of longitude, or meridians, run from pole to pole. Along the Prime Meridian
(which runs through Greenwich, UK), the Earth is divided into Eastern and Western
Hemispheres. Locations in the Eastern Hemisphere are denoted with an E (or a
positive number), while locations in the Western Hemisphere are denoted with a W
(or a negative number). The Prime Meridian is 0°E or 0°W, and increases to toward
180°E (or +180) or 180°W (or -180).
Latitude and longitude are measured in degrees, minutes, and seconds. Similar to a
clock, where one hour equals 60 minutes, and one minute equals 60 seconds, each
degree of latitude or longitude can be divided into 60 minutes (60’) and each
minute of latitude or longitude can be further subdivided into 60 seconds (60”). For
example, the White House in Washington, DC is located at 38° 53’ 51” N, 77° 02’
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11” W. Latitude and longitude can also be measured in decimal degrees, or degrees
and decimal minutes, by converting the minutes and/or seconds into decimal
fractions. Cardinal directions (North, East, South and West) are replaced with
positive or negative signs. Therefore, the absolute location of the White House in
decimal degrees would be 38.8976, -77.0365.
Click Exit Street View in the top right corner of the Google Earth 3D viewer.
Change your units to degrees, minute and seconds. (Refer to the GETTING
STARTED lab module for directions on how to change latitude and longitude
units).
Double-click and select Location A.
Question 5: What are the latitude and longitude coordinates for Location A?
A. 51N, 114E
B. 114S, 51 E
C. 51S, 114W
D. 51N, 114W
Double-click and select Location B.
Question 6: What are the latitude and longitude coordinates for Location B?
A. 53N 6E
B. 6N, 53E
C. 53S, 6W
D. 53N, 6W
Question 7: Which is closer – the distance between Location A and the
Equator or the distance between Location B and the Equator?
A. Location A and the Equator
B. Location B and the Equator
C. Locations A and B are the same distance from the Equator
D. Cannot discern from the information provided
Question 8: Which is closer – the distance between Location A and the
Prime Meridian or the distance between Location B and the Prime Meridian?
A. Location A and the Prime Meridian
B. Location B and the Prime Meridian
C. Locations A and B are the same distance from the Prime Meridian
D. Cannot discern from the information provided
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Double-click and select Location C.
Question 9: What are the latitude and longitude coordinates for Location C?
A. 50N, 68S
B. 50N, 68W
C. 50S, 68E
D. 50S, 68W
Question 10: Which is farther– the distance between Location B and the
Equator or the distance between Location C and the Equator?
A. Location B and the Equator
B. Location C and the Equator
C. Locations B and C are the same distance from the Equator
D. Cannot discern from the information provided
Question 11: Which is farther – the distance between Location A and the
Prime Meridian or the distance between Location C and the Prime Meridian?
A. Location A and the Prime Meridian
B. Location C and the Prime Meridian
C. Locations A and C are the same distance from the Prime Meridian
D. Cannot discern from the information provided
Collapse and uncheck GLOBAL PERSPECTIVE.
Turn off the latitude/longitude grid. Press CTRL + L. Mac users press + L.
MAP SCALES
Map scale (or scale) is the ratio of the distance between two features or absolute
locations on the map and the distance between the same two features or absolute
locations on the ground. Maps should provide a scale to the user; typically, map
scales are shown in the bottom margin of the map.
Map scales are expressed in the following ways:
Ratio Representative fraction Verbal scale (also called a lexical scale)
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Bar scale (also called a scale bar, graphic scale, or graphical scale).
An example of each of these map scales is illustrated below.
Scale Expression
Ratio 1:12,000
Representative Fraction (RF) 1/12,000
Verbal 1 inch equals 1,000 feet
Scale Bar
Expand MAP SCALES and then double-click and select Boothbay Harbor
(Note: The topographic map might take a few seconds to display). To close the
citation, click the X in the top right corner of the window.
Question 12: How is the scale on this map expressed or presented (Hint:
look toward the bottom of the map image)?
A. Scale bar and RF
B. RF and Verbal
C. Verbal and Ratio
D. Scale Bar and Ratio
If you enlarge (zoom in) or reduce (zoom out) of the map, the scale of the image
changes, but the scales found the map do not. It is important to note only a bar
scale can be used to make distance calculations to a map that is enlarged or
reduced because it is the only map scale that remains correct if the map size
changes.
If a bar scale is not provided, it is important to know how to calculate distance. In
Google Earth, the Ruler tool will help you calculate the approximate distance
between two (or more) points.
To calculate scale, we will use the equation
S =
where:
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S = scale
d = distance between two features on the map
D = distance between two feature on the ground
Whether using the metric system or the British/Imperial system, make sure that
you know the conversions between the units.
Metric Units
1 m = 100 cm
1 km = 1000 m
1 km = 100,000 cm
British/Imperial Units
1 ft = 12 in
1 mile = 5,280 ft
1 mile = 63,360 in
Now for an example that will use the scale equation (S =
) and British/Imperial
units.
Example 1: Two buildings are 8 inches apart on a map (d). The same buildings
are 16,000 feet apart on the ground (D). Calculate the scale of the map.
To calculate the scale, first let’s make sure that are units are the same. Currently,
the map units (d) are in inches and the ground units (D) are in feet. Therefore, we
will convert feet to inches.
We know there are 12 inches in a foot, so we can multiply D by 12 to convert the
distance on the ground from feet (ft) to inches (in).
D = 16,000 ft.
D = 16,000 ft. x 12 inches/ft. = 192,000 inches
Now we can use the equation
S =
S =
Because we are dividing the same unit in the numerator as the denominator, the
units (inches) cancel out.
S =
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Now we need to simplify the equation so that our numerator is a 1. We can do this
by dividing both the numerator and the denominator by 8.
S =
S =
This ratio can also be written as 1:24,000.
Example 2: Calculate the scale of a map in which the distance between two
features is 6” on the map (d) and 12 miles on the ground (D).
Again, to calculate the scale, we first need to convert distances into the same units.
There are 63,360 inches in a mile. If we multiply 12 miles by 63,360 we can
convert D into inches
D = 12 miles
D = 12 miles x 63,360 inches/mile = 720,360 inches
Now we can use the equation
S =
S =
=
Because we are dividing the same unit in the numerator as the denominator, the
units (inches) cancel out.
Now we need to simplify the equation so that our numerator is a 1. We can do this
by dividing both the numerator and the denominator by 6.
S =
=
This ratio can also be written as 1:126,720
Notice that Examples 1 and 2 have different map scales. The map scale in Example
1, at 1:24,000, is larger than the map scale in Example 2, at 1:126,760.
Large-scale maps are more zoomed in and therefore show more detail, but less
area. Conversely, small scale maps are more zoomed out and therefore show less
detail but more area. Figures 2 and 3 illustrate larger and smaller map scales.
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Example 3. What is the distance on a map (d) in centimeters between two
features if they are 5km apart on the ground (D) and the map has a scale (S) of
1:100,000?
First, we need to rearrange our equation so that we are solving for map distance
rather than scale.
S =
rearranged to d = S * D
Because Scale (S) is unitless, we do not have to worry yet about converting units.
To note, the Scale ratio of 1:100,000 can be rewritten as 1/100,000.
Figure 2. Map with a 1:24,000 scale (larger scale map) (USGS)
Figure 3. Map with 1:62,500 scale (smaller scale map) (USGS)
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d = S * D
d =
* 5km =
d = 0.00005km
Because we are solving for map distance (d), it is unlikely that the final answer will
be in kilometers, and far more likely to be in centimeters. So, we convert km to cm.
d = 0.00005km *
d = 5cm
Example 4. What is the distance on the ground in kilometers between two
features if they are 5cm apart on the map and the map has a scale of 1:50,000?
First, we need to rearrange our equation so that we are solving for map distance
rather than scale.
S =
rearranged to D =
Next, we solve the equation.
D =
=
⁄ =
= 250,000cm
Because we are solving for ground distance (D), it is unlikely that the final answer
will be in centimeters, and far more likely to be in kilometers. So, we convert cm to
km.
D =
⁄ = 2.5km
Question 13. Using Figure 4, calculate the distance on the ground, in miles,
between Mill Point and Oak Point. Assume we measured 5 inches as the map
distance, and know that the map scale is 1:63,360.
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Figure 4. Mill and Oak Points (USGS)
A. 5 inches * 63,360 inches = 316,800 inches = 60 miles
B. 5 inches * 63,360 inches = 316,800 inches = 5 miles
C. 5 inches / 63,360 inches = .0000799 miles = 41.7 feet
D. 63,360 inches / 5 inches = 12,672 inches = 2.4 miles
Question 14: What is the distance on a map in centimeters between two
features if they are 7.6 km apart on the ground and the map has a scale of
1:125,000?
A. 7.6 km * (1/125,000) = 0.0000608 cm
B. 7.6 km * (1/125,000) = 6.08 cm
C. 7.6 km / (1/125,000) = 95 cm
D. 7.6 km / (1/125,000) = 950,000 cm
Google Earth does not provide scale as a ratio, representative fraction, or a verbal
scale. It does, however, provide a bar scale, found in the lower left hand corner of
the screen. If it is not active, select View > Scale Legend.
Even if it seem counterintuitive, remember! the larger the distance on the bar
scale, the smaller the map scale. Likewise, the smaller the distance on the bar
scale, the larger the map scale.
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Double-click and select Squirrel Island 1.
Question 15: What is the approximate distance, in feet, represented by the
scale bar?
A. ~ 4000 ft
B. ~ 5800 ft
C. ~ 6600 ft
D. ~ 7400 ft
Uncheck Squirrel Island 1. Double-click and select Squirrel Island 2.
Question 16:What is the approximate distance, in feet, represented by the
scale bar?
A. ~ 1150 ft
B. ~ 1350 ft
C. ~ 1550 ft
D. ~ 1950 ft
Question 17: Which bar scale represents the smaller map scale – Squirrel
Island 1 or Squirrel Island 2?
A. Squirrel Island 1
B. Squirrel Island 2
C. They are the same
D. Unable to determine from information provided
Collapse and uncheck MAP SCALES.
CONTOURS
Contours are lines that connect places of equal elevation. A contour interval (CI) is
the elevation difference between two consecutive contour lines, and is commonly
provided in the margin of a map. In Figure 5, the CI is 10 feet, meaning each
consecutive contour line represents a 10 foot change in elevation.
Index contours are typically labeled and are have a heavier line weight than regular
contour lines. In Figure 5, the index contours are found every 50 feet (every 5
contour lines). The Index contours at 50, 100, and 150 feet are labeled on the
contour map.
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There some rules
regarding contour lines:
Contour lines always form a closed polygon (see A in Figure 5).
However, on some maps, contour lines
might run off the margin.
Contour lines spaced
closer together depict a steeper slope (see B
in Figure 5). In contrast, contour lines spaced farther apart
(wider spacing) depicts a gentler slope
or flat area.
Contour lines might touch where there is a
steep elevation change, like a steep slope or cliff. Contour lines never cross unless the cliff face
has an overhanging ledge (hidden contours are then depicted as dashed lines).
Concentric, closed contours denote a hill or summit (see C in Figure 5); whereas closed contours with hachure marks on the downslope side depicts a depression.
Wherever contour lines cross a river point, the lines point upstream and create a V-shaped pattern (see D in Figure 5).
Double-click and expand CONTOURS.
Double-click and select Boothbay Harbor. (Note: The topographic map might
take a few seconds to display). To close the citation, click the X in the top right
corner of the window.
A USGS 7.5” map will appear near Georgetown, Maine. You might have to pan and
zoom in or out to answer the following questions.
Question 18: What is the contour interval of this map?
A. 10 meters
B. 24,000 feet
C. 10 feet
D. 24,000 meters
Figure 5. Contours (USGS)
A
C
z
D
B
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Double-click and select MacMahan Island.
Question 19: What is the index contour interval shown on MacMahan
Island?
A. Every 20 feet
B. Every 40 meters
C. Every 50 feet
D. Every 100 meters
Unselect MacMahan Island. Double-click and select Red Squares.
Question 20: What is the highest elevation within the two squares?
A. 150 meters
B. 150 feet
C. 175 feet
D. 93 feet
Question 21: Within the right red square, determine the general
downstream direction of the river.
A. North
B. East
C. South
D. West
Question 22: Explain what contour rule helped you answer Question 21.
A. Contours are spaced close together
B. Contours form closed polygons
C. Contours form a V shape that points upstream
D. Contours form a V shape that points downstream
Question 23: Within these two red squares, where is the steepest slope
located?
A. Left edge of right square
B. Left edge of left square
C. Middle of right square
D. Middle of left square
Question 24: Within these two red squares, where is the flattest area?
A. Left edge of left square
B. Upper right corner of right square
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C. Upper center of left square
D. Upper center of right square
Uncheck Red Squares.
Double-click and select Slope 1. Next, change the elevation exaggeration to 2
(see GETTING STARTED lab module on how to change exaggeration).
Double-click and select Perspective view to see the landscape in three
dimensions.
Question 25: As you move from left to right across the yellow line, is the
elevation increasing or decreasing?
A. Increasing
B. Decreasing
C. Remaining flat
D. Unable to determine from information provided
Right-click on Slope 1 and then select Show Elevation Profile.
At the bottom of the screen is a cross section of the terrain for the yellow line. The
X axis of the elevation profile chart is the distance of the line, while Y axis of the
charge represents the elevation over the line distance. As you run the cursor along
the line, the corresponding location along the profile is identified. Additional
information regarding elevation, distance, and slope is found immediately above the
elevation profile.
Question 26: What is the approximate length of the profile line (distance),
in feet?
A. ~ 131 feet
B. ~ 161 feet
C. ~ 966 feet
D. ~ 5280 feet
Question 27: What is the change in elevation (the relief) from one end of
the line to the other, in feet?
A. ~ 131 feet
B. ~161 feet
C. ~ 966 feet
D. ~ 5280 feet
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Question 28: Slope is the rise (relief of the line) divided by the run
(distance of the line). Using your answers from the previous two questions,
calculate the percent slope of the line to the nearest integer.
*100 = (________ /_______) *100 = ______________
A. (131 feet / 161 feet) * 100 = 81%
B. (161 feet / 966 feet) * 100 = 17%
C. (966 feet / 5280 feet) * 100 = 18%
D. (966 feet / 161 feet) * 100 = 600%
Collapse and uncheck CONTOURS.
REMOTE SENSING
Remote sensing is the art and science of acquiring information about a feature or
phenomenon without being in direct contact of that feature or phenomenon. In this
part of the lab, you will explore land use and land cover change using satellite
imagery. For the rest of this lab, you will be working with Landsat satellite imagery,
which is considered the longest continuous global record of Earth’s surface.
Expand REMOTE SENSING and then click NASA Landsat Flyby.
Question 29: How long has Landsat been collecting data on Earth?
A. Since 1968
B. Since 1953
C. Since 1977
D. Since 1972
Question 30: Natural disasters like the Mount St. Helens eruption and urban
growth in places like Las Vegas are two uses of Landsat data. Based on the
video, name two additional physical geography topics – and their example
locations – for which Landsat imagery has been used.
A. Mosquito habitat, Mississippi & Oil exploration, Canada
B. Climate change, Antarctic & Flooding, North Carolina
C. Ecosystems, North Carolina & Mosquito habitat, Yemen
D. Oil exploration, Yemen & Farmland, Kansas
Uncheck NASA Landsat Flyby.
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Click Landsat Viewer. (Note: if the webpage does not open or takes too long
to load, open the web browser outside of Google Earth by choosing the browser
icon at the top left corner of the Google Earth Viewer.)
In the ESRI web site, go to the top right hand corner and select View larger. The
default image should be Mount St. Helens, in Washington, USA. If it is not, type
Mount St. Helens in the search field and then press Enter. To zoom in or out, use
any slider found in the top left-hand corner of an image area. Assume North is at
the top of these remotely sensed images.
The images in the left (1975) and center (2000) panels are called false color
composite images. The satellite sensors collect data from the non-visible portion of
the electromagnetic spectrum (that is to say, wavelengths outside of the visible
portion of the electromagnetic spectrum we see with our eyes). Specifically, the
images are displaying reflected infrared energy; these are wavelengths longer than
visible light. Vegetation reflects a great amount of this energy, and appears red in
these images. The image to the far right shows change or difference between the
1975 and 2000 images. For a further interpretation of colors, see the legends found
below the images.
Question 31: What direction was most impacted by the 1980 Mount St.
Helen’s eruption?
A. North
B. East
C. South
D. West
Question 32: How did you determine this from the remote sensing imagery?
A. The significant decrease in vegetation
B. The Swift Reservoir is smaller in the 2000 image
C. Spirit Lake in 1975 is now 2 separate lakes in 2000
D. Forests have grown back.
Type Las Vegas, Nevada in the search field and then press Enter. You can pan
or zoom in or out of the image to answer the following questions.
Question 33: What does the “white” in the change detection image (right
panel) represent?
A. Increased vegetation
B. Decreased vegetation
C. No change
D. Clouds
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Question 34: In which direction has the majority of urban growth occurred
between 1975 and 2000?
A. North
B. East
C. South
D. All directions
Question 35: What are the bright red (green in the change detection image)
rectangle features that are predominately found on the west side of Las
Vegas?
A. New casinos
B. New subdivisions
C. New golf courses
D. New water parks
Question 36: Is urbanization in this region linked to an overall increase,
decrease, or no change in vegetation land cover?
A. Increase
B. Decrease
C. Roughly the same
D. Unable to tell from information provided
Question 37: Present in both 1975 and 2000, what is the diagonal strip
running NE to SW through the middle of the city?
A. Dried river bed
B. Airport runway
C. The famous Las Vegas “Strip”
D. A major interstate highway
Collapse and uncheck REMOTE SENSING. You have completed Lab Module 2.