Chapter 1

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Geosystems
FIFTH EDITION
AN INTRODUCTION TO PHYSICAL GEOGRAPHY
Robert W. Christopherson
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Essentials of Geography

• The Science of Geography  
• Earth Systems Concepts  
• Location and Time on Earth  
• Maps, Scales, and Projections  
• Remote Sensing and GIS  

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The Science of Geography

• Geography from geo Earth and graphein to
  write 
• Geography is
• a method, not a body of knowledge
• holistic
• eclectic
• Geographers use spatial analysis
• Geographers use Earth systems science

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Geography is

• The science that studies the relationships among
• natural systems,
• geographic areas,
• society,
• cultural activities,
• and the interdependence of all of these over
  space.

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Physical Geography is

• The spatial analysis of all the physical elements
  and processes that make up the environment.

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Figure 1.2
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• Geographers use the scientific method

Figure 1
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Earth Systems Concepts

• Systems Theory
• System an interrelated set of things linked by
  flows of energy and matter.
• Open systems
• Closed systems
• System feedback
• System equilibrium

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Figure 1.3
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Leaf as a systemPhotosynthesis as a process
Figure 1.4
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Leaf as a systemRespiration as a process
Figure 1.4
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System Behavior Equlibrium
Dynamic Equlibrium
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Are Systems Stable?

• Are Systems Stable?
• Energy is not evenly distributed throughout the
  environment.
• When energy changes it does work.
• Can we see the changes in the environment
  (system)?
• Over time systems tend to keep a general
  structure (equilibrium).
• Trends
• Change in the average behavior of the system.
• Feedback mechanisms.
• A modification of a process that either amplifies
  (positive feedback) or dampens out (negative
  feedback) subsequent processes in a system.

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Atmosphere as a System
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System behavior Trend Change in the average
behavior of the system
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Trend
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Feedback

• A modification of a process that either amplifies
  (positive feedback) or dampens out (negative
  feedback) subsequent processes in a system.

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Do systems have a boundary?

• Internal flow vs. flow across systems
• Is the Earth an open or closed system?

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Earths Four Spheres

• Atmosphere
• Hydrosphere
• Lithosphere
• Biosphere

Figure 21.2
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Earths dimensions
Figure 1.9
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Measuring Earth in 247 B.C.
Figure 1.10
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Location and Time on Earth  

• Latitude
• Longitude
• Great circles
• Prime Meridian and standard time

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Latitude
High Latitude Polar regions Low
Latitude Tropics
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Latitude
Latitude An angular distance north and south of
the equator
Figure 1.11
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Longitude
Figure 1.14
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Longitude
Figure 1.14
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Prime Meridian and Standard Time  
Figure 1.17
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Prime Meridian and Standard Time  
Figure 1.17
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Great Circles and Small Circles
Figure 1.15
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Maps, Scales, and Projections  

• Map a generalized view of an area, as seen from
  above and reduced in size
• Scale ratio of map units to ground units
• Projection process of transforming spherical
  Earth to flat map

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Planar Projection
Classes of Projections
Figure 1.22
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Cylindrical
Eg. Mercator projection
Figure 1.22
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Conic projection
Figure 1.22
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Classes of Projections
Figure 1.22
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Remote Sensing

• Active remote sensing
• Passive remote sensing

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Active and Passive Remote Sensing
Passive sensing visible light
Active sensing radar
Figure 1.25
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Remote Sensing
Figure 1.26
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Geographic Information Systems (GIS) 

• GIS systems combine spatial and attribute data 
• Maps can contain multiple data layers
• Physical features
• Cultural features
• Layers can be added to create composite overlay

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GIS
Figure 1.28