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Chapter 1

Essentials of

Geography

Robert W. Christopherson

Charlie Thomsen

• The science that studies the relationships

among

– natural systems

– geographic areas

– society

– cultural activities

– and the interdependence of all of these over

space

Geography Is

• PG: studies the physical elements and

processes that make up the natural environment

• HG: studies patterns and processes that make up the human environment

No strict boundaries, human environment have to exist on the Earth

surface, and human activities modify the natural environment.

Physical/Human Geography

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Figure 1.2

Geographer’s Perspectives of the World

Location Matters

Real-world Relationships

Horizontal connection among places

Importance of Scale (both in time and space)

Scientific Method

Figure FS 1.1.1

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• Systems theory

• Open systems

• Closed systems

• System feedback

• System equilibrium

Earth Systems Concepts

• A System is any ordered, interrelated set

of entities and their attributes, linked by flows of energy and matter, as distinct

from the surrounding environment out side the system:

e.g. a car, a house, a pound, a watershed, a hurricane, the ocean, the earth, …

Earth Systems Concepts

• Reservoir/Stock/the state variable: a repository where matter/energy is stored over time.

• Processes (flows of energy/matter): the activities in the system that determines the content of the reservoir over time.

• Parameters: which regulate the rate of change in the processes.

• Relationships: connections among the components of system.

System Components

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System Components: ExamplesA pound as a system:

Stock:

flows:

parameters:

relationship:

Timber resources in a forest farm as a system:

Stock:

Flows:

parameters:

relationship:

1. Open/Closed Systems

2. System Feedbacks

Positive Feedback: unstable

Negative Feedback: stable

3. System Status:

Growth/Decline

Steady-State

System Properties

Figure 1.3

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Open Systems

Figure 1.4

Systems in Steady State

Figure 1.5

01_0 5. JPG

Steady-state is not static, but dynamic. A steady-state system can withstand

certainly level of disturbance and the system can regain its steady-state. After a threshold (tipping point), the system will be permanently displaced

and regain new steady-state.

Tipping Point Example

Figure 1.5

Harlequin Frog:

Monteverde Cloud Forest Reserve, Costa Rica

Moist and porous skin: fungus penetration

Global Warming

More Water in the air

More Clouds over Mountains

Increase nighttime minimum T

Decrease daytime maximum T

Chytrid fungus:

ideal T: 17~25oCstop grow: 28oC

dies: 30oC

1986-2006:

67% of the 110 known

species of Harlequin frog extinct.

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Earth’s Four Spheres

Figure 1.8

Earth System Characteristics

Figure 1.8

1. A dynamic evolving system: energy and matter are constantly being transferred and changing in form.

2. An open system with respect to energy.

3. A nearly steady-state system in energy.

4. A almost closed system with respect to matterexception: air molecules escape earth gravity to leave the Earth system, and meteorites from outer space.

Earth Dimensions

Figure 1.9

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Measuring Earth in 247 B.C. by

Eratosthenes

Figure 1.10

1 statium=185 m,

5000*185m*50=46,250km

• Latitude

• Longitude

• Great circles

• Prime Meridian and standard time

Location and Time on Earth

Latitude/Parallel

Figure 1.11

Latitude: angles

Parallels: the line

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Latitudinal Geographic Zones

Figure 1.12

Longitude

Figure 1.13

Time

Greenwich Mean Time (GMT): Local time for the prime meridian.

Eastern Standard Time: Local time for the meridian of 75oW(Central Time, Mountain Time, Pacific Time, Alaska Time)

Beijing time: Local time for the meridian of 120oE

Local Time: Local noon: The instant that the local meridian swipe across the sun

is defined as the local noon.

For scientific calculation, we often need local time

e.g. how high the sun is in the sky?

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Prime Meridian and Standard Time

Figure 1.17

• Map –A graphic depiction on a flat medium of all or part of a geographic realm in which real world features have been replaced with symbols in their correct spatial location at a reduced scale.

• Scale – ratio of map units to ground units

Large/small scale

fine/coarse scale

• Projection – process of transforming points on 3D spherical Earth Surface to 2D flat medium (e.g. paper).

Maps, Scales, and Projections

Figure 1.21

Classes of

Map

Projections

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• GIS is a computer system that allows visualization, storage, analysis and update of geographic data (spatial and attribute data)

• GIS can create digital maps that contain multiple data layers:

– Physical features (rivers, forests, topographic

– Cultural features (populations, economic, social…)

• Layers can be added to create composite overlay

• Many modern environmental problems need many layers of Geographic data and Geographers play pivotal roles in help us understand or find solutions or mitigate these problems.

Geographic Information Systems (GIS)

GIS System Model

Figure 1.29