Introduction to Geographic

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• Introduction to Geographic
• Information Systems

Dr. Larry Teeter
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(No Transcript)
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What is a GIS?
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One of a Set
Geospatial technologies are technolo-gies for
collecting and dealing with geographic
information. There are three main types
Global Positioning Systems Remote
Sensing Geographic Information Systems
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Defining GIS

• Different definitions of a GIS have evolved in
  different areas and disciplines
• All GIS definitions recognize that spatial data
  are unique because they are linked to maps
• A GIS at least consists of a database, map
  information, and a computer-based link between
  them

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Definition 1 Duekers Feature Model

• "A geographic information system is a special
  case of information systems where the database
  consists of observations on spatially distributed
  features, activities or events, which are
  definable in space as points, lines, or areas. A
  geographic information system manipulates data
  about these points, lines, and areas to retrieve
  data for ad hoc queries and analyses" (Dueker,
  1979, p 106).

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Definition 2 A GIS is an information system

• "An information system that is designed to work
  with data referenced by spatial or geographic
  coordinates. In other words, a GIS is both a
  database system with specific capabilities for
  spatially-referenced data, as well as a set of
  operations for working with the data" (Star and
  Estes, 1990, p. 2).

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Definition 3 Paul Bolstads Definition(author
of class text)

• a computer-based system to aid in the
  collection, maintenance, storage, analysis,
  output, and distribution of spatial data and
  information

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Definition 4 GIS is a multi-billion dollar
business.

• The growth of GIS has been a marketing
  phenomenon of amazing breadth and depth and will
  remain so for many years to come. Clearly, GIS
  will integrate its way into our everyday life to
  such an extent that it will soon be impossible to
  imagine how we functioned before

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• We usually understand GIS to be
  computer-facilitated system
• GIS is NOT only software/hardware
• Also includes
• Trained personnel
• Supporting Institution
• Protocols for use

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Why Learn GIS?..... Because GIS is Everywhere
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• Why computerize manual methods?
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• To bring together data from multiple sources
  (synthesis)
• Analytical power
• measure distance, density, area
• overlay and buffer
• adjacency and proximity
• vicinity (neighborhood)
• networks
• intervisibility
• Flexibility
• Output Quality

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Why GIS?

• Resource depletion/degradation
• Increased problem complexity
• Demands by the body politic
• Improved capabilities
• Increased competition

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Why GIS?

• Expanded capabilities - do the heretofore
  impossible
• Improved efficiency - reduce speed of analysis
  10-fold or more

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Why GIS? Traffic Information
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Monitoring and Mapping Sea Ice in near Real Time
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Why GIS?
Pavement quality inventory and monitoring
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Why GIS?

• Sustaining Lobster Fisheries in Penobscot Bay
• Why is it important? Fisheries stocks dwindling,
  lobster an economic mainstay with sustainable
  harvests

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From Observations and Process Knowledge to
Prediction and Action
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Where did GIS come from?

• GIS is built upon knowledge from geography,
  cartography, computer science and mathematics
• Geographic Information Science is a new
  interdisciplinary field built out of the use and
  theory of GIS

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Basic Concepts of a GIS - spatial data from
different data sources are registered to same
scale to form data planes (layers) - These data
are used together (overlaid) to produce a
variety of derived information - data layers
resource manager might use land
ownership transportation networks right of
way utilities land use vegetation
cover surface water endangered
species elevation soil type jurisdictional
boundaries pest disease
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Questions a user might ask of a GIS -Where is
object A (RCW cavity trees)? -Where is A in
relation to place B? -How many occurrences of
type A are within distance X of B? -What is the
value of function Z (distance from parking area)
at position X?-How large is B (campground area,
perimeter)
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A Brief History of GIS

• GISs origins lie in thematic cartography
• Many planners used the method of map overlay
  using manual techniques
• Manual map overlay as a method was first
  described comprehensively by Jacqueline Tyrwhitt
  in a 1950 planning textbook
• McHarg used blacked out transparent overlays for
  site selection in Design with Nature

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A Brief History of GIS (cont.)

• The 1960s saw many new forms of geographic data
  and mapping software
• Computer cartography developed the first basic
  GIS concepts during the late 1950s and 1960s
• Linked software modules, rather than stand-alone
  programs, preceded GISs

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A Brief History of GIS (cont.)

• Computerized GIS began in mid - 60's
• - CGIS - 1964
• - MLMIS - 1969
• - FRIS - early 70's
• - required mainframe computers
• - mini computers made technology more
  accessible (early 80's)

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A Brief History of GIS (cont.)

• GIS was significantly altered by (1) the PC and
  (2) the workstation
• During the 1980s, new GIS software could better
  exploit more advanced hardware
• User Interface developments led to GIS's vastly
  improved ease of use during the 1990s
• During the 1980s, new GIS software could better
  exploit more advanced hardware

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Features as Objects

• The standard feature model divides a mapped
  landscape up into features, that can be points,
  lines, or areas.
• Almost all human activity and natural phenomena
  are spatially distributed, so can be studied
  using a GIS.
• A GIS uses map features to manage data.

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