This document discusses various methods for portraying and understanding features on Earth's surface. It introduces maps, their essential properties, scales, and projections. Globes are also covered, along with their advantages and disadvantages relative to maps. Remote sensing techniques like aerial photography, infrared scanning, radar, and sonar are explained. Finally, geographic information systems (GIS) are introduced as computer tools to analyze and display spatial data in layers, helping geographers better understand Earth.

1. Chapter 2: Portraying Earth
McKnight’s Physical Geography:
A Landscape Appreciation,
Tenth Edition, Hess

2. Portraying Earth
• The Nature of Maps
• Map Scale
• Map Essentials
• The Role of Globes
• Map Projections
• Families of Map Projections
• Isolines
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3. Portraying Earth
• GPS—Global Positioning System
• Remote Sensing
• GIS—Geographic Information Systems
• Tools of the Geographer
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4. The Nature of Maps
• 2-dimensional
representation of
Earth’s surface
• Show 4 key properties
of a region
– Size
– Shape
– Distance
– Direction
• Maps are imperfect, since
Earth is a sphere
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Figure 2-2b

5. Map Scale
• Maps are always smaller than
the area they represent
• Map scales are necessary to
understand realistic distances
on map
• Scale is relationship between
area on map and area on
Earth
• Three primary types
– Graphic
– Fractional
– Verbal
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Figure 2-3

6. Map Scale
• Large versus small map scales
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Figure 2-4

7. Map Essentials
• Need several properties
of maps to help with
interpretation:
– Title
– Date
– Legend
– Scale
– Direction
– Location
– Data Source
– Map Projection
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Figure 2-5

8. The Role of Globes
• Advantages of Globes
– Maintains correct geographic
relationships between points
– Can accurately represent spatial
relationships between points on
Earth
• Disadvantages of Globes
– Only can see a hemisphere at a
time
– Large and bulky
– Cannot contain much detail
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Figure 2-6

9. Map Projections
• Challenge of the cartographer (“mapmaker”)
– Combine geographic exactness of globe with convenience of
flat map
• Definition of map projection
• Principle behind map projections
• Two primary types
– Equivalent—ratio of areal size on map and Earth is the same
– Conformal—shape of locations on the map is the same as on
Earth
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10. Map Projections
• Equivalence versus conformality dilemma
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Figure 2-10

11. Families of Map Projections
• Cylindrical Projections
– “Wrap” the globe in a
cylinder of paper
– Paper tangent to Earth
at equator
– Conformal projection
– Mercator projection is
most famous
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Figure 2-7

12. Families of Map Projections
• Plane Projections
– Project globe onto a
paper that is tangent to
globe at some point
– Displays one
hemisphere well
– Equivalent projection
– An example is an
orthographic plane
projection (Figure 2-13)
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Figure 2-9

13. Families of Map Projections
• Conic Projections
– Project the map onto a
cone tangent to or
intersecting the globe
– Principal parallel
– Good for mapping
small areas on Earth
– Impractical for global
mapping
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Figure 2-8

14. Families of Map Projections
• Pseudocylindrical
Projections
– A mix of conformal and
equivalent
– Central parallel and
meridian cross at right
angles
– Oval shaped; distortion
increases as you move
away from the center
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Figure 2-11

15. Families of Map Projections
• Interrupted Projections
– Minimize distortion
– Discontinuous map,
shapes and sizes
maintained
– Typically oceans are
distorted; land masses
maintain original
shape and size
– Goode’s projection
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Figure 2-14

16. Isolines
• Definition
• Many types
– Isobar: line of constant
pressure
– Isotherm: line of constant
temperature
– Isohyet: line of constant rain
– Isoamplitude: line of
constant wave amplitude
• Construction steps/rules
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Figure 2-16

17. Isolines
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800
700
600 500 400
300

18. Isolines
• Topographic Maps
– Show elevation
contours
– Contour lines
– Lines closer together
represent steeper
terrain
– Often used in
geography
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Figure 2-15

19. Isolines
• Topographic Maps
– Show elevation
contours
– Lines closer together
represent steeper
terrain
– Often used in
geography
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Figure 2-15

20. GPS—Global Positioning System
• Global navigation satellite
system for determining
location on Earth’s
surface
• Wide Area Augmentation
System (WAAS)
• Continuously Operating
GPS Reference Stations
(CORS)
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Figure 2-19

21. Remote Sensing
• Measurement by a device
not in contact with Earth’s
surface
• Common types include:
– Aerial Photographs
– Orthophoto maps
– Visible Light and Infrared
(IR) Scanning
– Thermal IR scanning
– Radar and Sonar
– Many others
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Aerial Photography—Figure 2-20

22. Remote Sensing
• Orthophoto maps
– Photographic maps that
are multicolored and
distortion free
– Useful in low-lying coastal
regions to show marsh
topography
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Figure 2-21

23. Remote Sensing
• Visible light and IR
scanning
– Based off of visible light and
IR part of electromagnetic
spectrum (Figure 2-22)
– Shows “false color”
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Figure 2-23
Figure 2-22

24. Remote Sensing
• Radar Imagery
– “Radio Detection and Ranging”
– Useful for identifying atmospheric moisture
• Sonar Imagery
– “Sound Navigation and Ranging”
– Permits underwater imaging
• Thermal IR scanning
– Scans in the thermal IR part of spectrum
– Shows images based on temperature
– Often utilized in meteorology
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25. GIS—Geographic Information
Systems
• Computer systems used to
analyze and display spatial
data
• Layers of data used in
mapping
• Requires high powered
computing to process
multiple maps
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Figure 2-29

26. Tools of the Geographer
• Vast array of maps, remotely sensed satellite
imagery, and computer applications
• Difficult to determine the best way to use all of
this information
• Some tools better at identifying features on
Earth than others
• Ultimate goal: “To better understand Earth.”
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27. Summary
• Maps are essential to portray features on Earth’s
surface
• Need a map scale to identify how a map relates
to the actual surface features on Earth
• Many other map properties are essential to
interpreting a map
• Globes have several advantages and
disadvantages
• Representing Earth in 2 dimensions can be done
through map projections
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28. Summary
• Many different map projections exist
• Dilemma of equivalent versus conformal
• Plotting isolines on a map can help with
interpretation of features on the map
• The global positioning system (GPS) helps to
identify location on Earth’s surface
• Remote sensing is a measurement of Earth’s
surface from a system not on Earth’s surface
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29. Summary
• Many different remote sensing instruments
exist, including satellite, radar, and sonar
• GIS are computer systems used to analyze and
display spatial data, often in layers
• The geographer has many tools, but the
ultimate goal is “To better understand Earth.”
29© 2011 Pearson Education, Inc.