Title: Chapter 1
1Geosystems
FIFTH EDITION
AN INTRODUCTION TO PHYSICAL GEOGRAPHY
Robert W. Christopherson
2Chapter 1 Essentials of Geography
- Geosystems 5e
- An Introduction to Physical Geography
Robert W. Christopherson Charlie Thomsen
3Key Learning Concepts
- After reading the chapter you should be able
to - Define geography and physical geography in
particular. - Describe systems analysis, open and closed
systems, feedback information, and system
operations, and relate these concepts to Earth
systems. - Explain Earths reference grid latitude and
longitude, and latitudinal geographic zones and
time. - Define cartography and mapping basics map scale
and map projections. - Describe remote sensing and explain geographic
information system (GIS) methodology as a tool
used in methodology as a tool used in geographic
analysis.
4The Science of Geography
- Geography from geo Earth and graphein to
write - Geography is
- A method, not a body of knowledge
- Holistic (relating to or concerned with wholes or
with complete systems rather than with the
analysis of, treatment of, or dissection into
parts). - Eclectic (composed of elements drawn from various
sources). - Geographers use spatial analysis (the examination
of spatial interactions, patterns, and variations
over area/or space. Geography is a spatial
science spatial analysis its essential
approach). - Spatial- The nature or character of physical
space, as in an area occupying or operating
within space.
5What is the Science of Geography?
- Geography is the science that studies the
interdependence of geographic areas, places, and
locations natural systems processes and
societal and cultural activities over Earth's
surface. Physical geography involves the spatial
analysis of Earth's physical environment.
Various words denote the geographic context of
spatial analysis space, territory, zone,
pattern, distribution, place, location, region,
sphere, province, and distance. Spatial patterns
of Earth's weather, climate, winds and ocean
currents, topography, and terrestrial biomes are
examples of geographic topics.
6Example of what physical geographers do
- Question How might a physical geographer
analyze water pollution in the Great Lakes? - Answer Geographers for example can describe the
lake elevations, flows, volumes and annual mixing
patterns as temperatures change seasonally. They
can locate population centers and point sources
of pollution using population concentrations
estimate non-point sources of pollution. They can
map published data of water chemical analyses.
They can use a Geographic Information System
(GIS) model develop a composite overlay of all
the above elements.
7Geographic themes
- The Association of American Geographers (AAG) and
the National Council for Geographic Education
(NCGE), set forth five key themes for modern
geographic education location, place,
human-Earth relationships, movement, and region.
8The five geographic themes
- Location Either absolute or relative location.
Location answers the question where? or the
specific planetary address of a location. - Region Portion of the Earths surface with
uniform characteristics how they form and
change how they relate to other regions. - Human-Earth Relationship Humans and the
environment resource exploitation, hazard
perception, and environmental modification- the
oldest theme of geographic inquiry. - Place The characteristics that make each place
unique (realistic or spiritual). - Movement Communication, movement, circulation,
and diffusion across Earths surface. Global
interdependence links all regions and places-
both physical and human systems.
9Geography is also
- The science that studies the relationships among
- natural systems,
- geographic areas,
- society,
- cultural activities,
- and the interdependence of all of these over
space.
10Content of Geography
- Geography derives subject matter from many
different sciences. The focus of this class is
physical geography but geographers also integrate
some human and cultural components. Synthesis of
Earth topics and human topics is suggested by
movement toward the middle of the continuum- a
holistic, or balanced view. (See Figure 1.2-
next slide).
11Figure 1.2
12Scientific Method
- Like all other sciences, geographers use the
scientific method approach that uses applied
common sense in an organized and objective
manner based on observation, reasoning,
hypothesis, predictions, and finally the
development of a theory. - Observation What data are needed? What do we
want to know? What questions need answering? - Reasoning Explanation and interpretation.
Building useful models of real systems-
conceptual, numerical. - Hypothesis General statement summarize data,
observations, and model simulations. - Predictions Experiments conducted more data
gathered through observation and measurement
hypothesis refined. - Theory Real world understood the knowledge of
how things happen and behave as part of broad,
general principles.
13- Figure 1 Page 7 Geographers use the scientific
method- from perceptions, to observations,
reasoning, hypothesis, predictions, and possibly
to general theory and natural laws.
14Earth Systems Concepts
- Systems Theory Geographers use systems
methodology as an analytic tool. A system is any
ordered, interrelated set of things and their
attributes, linked by flows of energy and matter,
as distinct from the surrounding environment
outside the system. - Open systems A system with inputs and outputs
crossing back and forth between the system and
the surrounding environment. Earth is an open
system in terms of energy-why? Other examples are
the automobile and a leaf (see next 2 slides). - Closed systems A system that is shut off from
the surrounding environment so that it is
entirely self-contained in terms of energy and
materials Earth is a closed system in terms of
physical matter and resources.
15More systems
- System feedback As a system operates, it
generates outputs that influence its own
operations. These outputs function as
information that is returned to various points
in the system via pathways called feedback
loops. Feedback loops can guide further system
operations. Example In plant photosynthesis
any increase or decrease in daylight or water
can cause a decrease in growth of a plant. - System equilibrium A system that maintains
structure and equilibrium over time. The rates
of inputs and outputs in the system are equal and
the amounts of energy and matter are constant.
Examples the rotations of planets. Gradual
change of the system is defined as Dynamic
equilibrium. Examples Long term climatic
changes, increasing temperatures of the
atmosphere and oceans.
16Figure 1.3
17Open system Photosynthesis in plants create
consumption of light, CO2, nutrients, and H2O and
produces oxygen and sugars while at night much of
the reverse takes place.
Figure 1.4
18Earths Four Spheres
- Atmosphere
- Hydrosphere
- Lithosphere
- Biosphere
Figure 21.2
19Earths Four Spheres- Plan for the Course.
- Atmosphere (Chap. 2-6). The atmosphere is a
thin veil of gases surrounding the Earth, which
form a protective boundary between outer space
and the biosphere generally considered to extend
about 480 km from the surface. - Hydrosphere (Chap. 7-10) An abiotic (non
biological) open system that includes all of the
Earths water. - Lithosphere (Chap. 11-17). Earths crust and a
portion of the upper mantle directly below the
crust form the lithosphere. - Biosphere (Chap. 18-20). The intricate,
interconnected web that links all organisms with
their physical environment.
20Earths Dimensions, Location, and Time
Calculations
- Dimensions
- Latitude
- Longitude
- Great circles, Small Circles
- Prime Meridian and standard time
21(Figure 1.9) Earths dimensions Earth
circumference (a) and diameter (b)- equatorial
and polar - are shown. The dashed line is a
perfect circle for reference to Earths geoid
(the surface within or around the earth that is
everywhere normal to the direction of gravity and
coincides with mean sea level in the oceans).
Figure 1.9
22Latitude
- On a map or globe, lines denoting angles of
latitude run east and west, parallel to Earth's
equator. Latitude is an angular distance north
or south of the equator measured from a point at
the center of Earth. A line connecting all
points along the same latitudinal angle is called
a parallel. (See next slide.)
23Latitude
Figure 1.11
24Longitude
- On a map or globe, lines designating angles of
longitude run north and south at right angles
(90) to the equator and all parallels. Longitude
is an angular distance east or west of a surface
location measured from a point at the center of
Earth. A line connecting all points along the
same longitude is called a meridian. (See next
slide.)
25Longitude
Figure 1.14
26Great Circles and Small Circles
- A great circle is any circle of Earth's
circumference whose center coincides with the
center of Earth. Every meridian is one-half of a
great circle that crosses each parallel at right
angles and passes through the poles. An infinite
number of great circles can be drawn on Earth,
but only one parallel is a great circlethe
equatorial parallel. All the rest of the
parallels diminish in length toward the poles,
and, along with other circles that do not share
Earth's center, constitute small circles (See
next slide).
27Great Circles and Small Circles
Figure 1.15
28Prime Meridian and Standard Time
- Prime Meridian the meridian of 0 degrees
longitude which runs through the original site of
the Royal Observatory at Greenwich, England, and
from which other longitudes are measured east or
west. Greenwich, England was selected by
international agreement in an 1884 treaty.
Greenwich Mean Time (GMT) became the world
standard time. (See next slide). - International Date Line An important corollary
of the prime meridian is the 180 degrees meridian
on the opposite side of the planet. The meridian
is called the International Date Line (IDL) and
marks the place where each day officially begins
(at 1201 A.M.). From this line the new day
sweeps westward. The westward movement is
created by the Earth turning eastward on its
axis. The IDL deviates from the 180 degrees
meridian, this deviation is due to local
administrative and political preferences. (See
next slide).
29Figure 1.17 Prime Meridian and Standard Time
Figure 1.17
30What does timekeeping have to do with longitude?
How is Coordinated Universal Time (UTC)
determined on Earth?
- Earth revolves 360 every 24 hours, or 15 per
hour, and a time zone of one hour is established
for each 15 of longitude. Thus, a world
standard was established, and time was set with
the prime meridian at Greenwich, England. Each
time zone theoretically covers 7.5 on either
side of a controlling meridian and represents one
hour. Greenwich Mean Time (GMT) is called
Coordinated Universal Time (UTC) and although
the prime meridian is still at Greenwich, UTC is
based on average time calculations kept in Paris
and broadcast worldwide. UTC is measured today
by the very regular vibrations of cesium atoms in
6 primary standard clocksthe NIST-F1 being the
newest placed in operation by the United States
in 2000.
31Maps, 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
32Maps
- A picture -- or a map -- is worth a thousand
words! A map is a simplified view of the earth's
surface that shows where places and things are
located and helps us communicate that information
efficiently. In this section, you will learn more
about maps and how to read them.
33Reading Maps
- Common Elements
- Maps have certain common elements that help us
read them effectively.
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35- On a map, the title indicates the geographic area
depicted on the map.
36- On a thematic map, the title also indicates the
data being presented on the map.
37Legend
- The legend is the key to understanding the map
and, together with the title, is the first place
you should look when reading a map. The map
legend explains the meaning of symbols used on
the map.
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39Scale
- Scale is a statement of how distance on the map
relates to distance on the ground. - Two common expressions of scale are
- Representative fraction
- Graphic Bar (or bar scale)
40Representative fraction
- Example of Representative fraction
- 163,360
- Meaning 1 unit of distance on the map equals
63,360 of the same units on the ground. The ratio
is universal 1cm on the map 63,360 cm on the
ground or 1 inch on the map 63,360 inches on
the ground.
41Graphic Bar (or bar scale)
- Example Use the graphic scale printed on the map
to measure distances on the map in terms of
ground distances.
42Small scale or large scale?
- Small scale less detail (more land coverage),
for example 11,000,000. - Large scale more detail (less land coverage),
for example 110,000. - Sometimes, small scale maps contain "insets" at a
larger scale to show detail in a congested area
of the small scale map. (See next slide).
43Example
44- DIRECTION Most maps include a "north arrow (see
below) to reference direction on the map. Maps
produced by Statistics Canada usually show "true
north", which is the direction to the North Pole
of the earth, rather than magnetic north or grid
north. The north arrow on a map is usually
located in or near the map legend. If a north
arrow does not appear on the map, north is
assumed to be the top of the map -
- There are other types of "north" that can be
shown on maps. Most topographic maps will show
the difference between true, magnetic and grid
north. Magnetic north is the north magnetic pole.
It is currently located in Nunavut at 78oN 105oW.
The north arrow of a magnetic compass points
toward the north magnetic pole. (Note the
difference between true north and magnetic north
is call ed magnetic declination.) - Grid north is an artificial north that is used on
map which have a rectangular grid. The vertical
lines do not converge as one proceeds northward.
These map are most commonly used for navigation.
45Features
- Thematic maps use symbols to display a specific
data theme such as population change,
distribution of lone-parent families, average
farm income, etc. A minimum amount of reference
information, such as boundaries and major water
features, help map readers orient themselves to
the geographic area covered by the map.
46Example
47Features (continued)
- Reference maps use symbols to show the location
of physical features, such as roads, railroads,
rivers, lakes, etc., and non-visible features
such as boundaries, names and codes of geographic
areas (See next slide)..
48Example
49Classes of Map Projections
- A globe is the only true representation of
distance, direction, area, shape, and proximity.
A flat map distorts those properties. Therefore,
in preparing a flat map, the cartographer must
decide which characteristics to preserve, which
to distort, and how much distortion is
acceptable. Four general classes and
perspectives of map projections are used by
cartographers cylindrical, planar, conic, and
oval. (See next slide).
50Classes of Map Projections
Figure 1.22
51Modern Earth Measurements Remote SensingWhat is
remote sensing? What are you viewing when you
observe a weather image on TV?
- Remote Sensing Our eyes and cameras are familiar
means of obtaining remote-sensing information
about a distant subject without having physical
contact. Remote sensors on satellites and other
craft sense a broader range of wavelengths than
can our eyes. They can be designed to see
wavelengths shorter than visible light
(ultraviolet) and wavelengths longer than visible
light (infrared and microwave radar). - Active remote sensing Active systems direct a
beam of energy at a surface and analyze the
energy that is reflected back. An example is
radar (radio detection and ranging). - Passive remote sensing Passive remote-sensing
systems record energy radiated from a surface,
particularly visible light (like our eyes) and
infrared.
52Active and Passive Remote Sensing
Passive sensing visible light
Active sensing radar
Figure 1.25
53Remote Sensing
Figure 1.26
54Geographic 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
55Geography and Technology
- Geography affects us in many ways
- Our natural environment
- Our human environment
- Geography is a Hi-Tech discipline
- Earth Observation
- Global Positioning Systems (GPS)
- Geographic Information Systems (GIS)
56Earth Observation
57Geographic Information Systems
- We can describe any element of our world in two
ways
Describing Our World
58GIS - Links Data Sets
- GIS software links the location data and the
attribute data
59GIS - Analysis
- GIS software can answer questions about our world
60GIS - Layers
- GIS contains many layers of information
These are just a few of the kinds of layers a GIS
can contain
61GIS - Analysis
- GIS can analyze data in many ways
62GIS Technology
- GIS borrows from other software technology
63Summary - What is GIS?
- GIS is about using data to describe our world in
two ways - Location Data - Where is it?
- Attribute Data - What is it?
- GIS software maintains a link between layers of
location and attribute data - With the Link, we can ask questions about our
world
64Real World Applications
- Environmental
- Park Management
- Agriculture
- Public Utilities
- Health Care
- Emergency 911
- Real Estate
- Marketing
65Park Management
- Will the new building spoil the Park Scenery?
Park planners use Geotechnology to determine if a
new Visitor Centre can be seen from the peak.
66Agriculture
- How can I improve food production?
Geotechnology is used in making crop management
decisions to maximize yields and minimize
fertilizer input.
67Public Utilities
A proposed excavation, identified by address, is
compared to pipelines in the area using
Geotechnology.
68Health Care
- What Communities are at risk from Disease?
Geotechnology identifies communities at risk of
River Blindness and helps determine the impact of
treatment.
69Emergency 911
- What is the fastest route to the Hospital?
Geotechnology can choose the fastest route to a
hospital. The GIS can take into account traffic
and other impediments.
70Real Estate
With Geotechnology, an agent can show a map of a
neighborhood and a picture or video of the actual
properties.
71Marketing
- How can I optimize my Marketing Campaign?
Geotechnology can query a database and identify
only those areas with the highest household
income within a specified distance of a store.
72End of Chapter 1
- Geosystems 5e
- An Introduction to Physical Geography
Robert W. Christopherson Charlie Thomsen