Geographic Information System

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Geographic Information System

• Geog 258 Maps and GIS
• February 17, 2006

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Outlines

• What is GIS?
• What can GIS do?
• GIS applications
• Components of GIS
• What is special about GIS?
• GIS and geographic questions

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What is GIS?

• An information system that is designed to work
  with geographically referenced data

Image from esri.com

• Information system hardware, software, database
• Geographically referenced data coordinate system

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What is GIS?Different views

• Functionalities view
• A system for capturing, storing, retrieving,
  manipulating, analyzing, and displaying data
  which are spatially referenced to the Earth --
  Chorley, 1987
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• Information system view
• Geographic Information System (GIS) is a kind of
  Information System (IS) designed to work with
  geographically referenced data
•  
• Database view
• A database system with specific capabilities for
  spatially-referenced data, as well as a set of
  operations for working analysis with the data
  -- Start and Estes, 1990
•  
• Disciplinary view
• GIS as a multidisciplinary science GIS is an
  integrated multidisciplinary science consisting
  of the following traditional disciplines.

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Themes are organized spatially

• GIS organizes the information about place by
  layers

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Themes are put into a computer
Modeling the phenomenon
Group of spatial objects with related entity type
e.g. city layer, SARS layer, Tornado layer
Layers
Abstraction
Digital Representation of Spatial Entities
e.g. point, line, polygon
Spatial Objects
Phenomenon of interest in the real world
Spatial Entities
e.g. urban growth, Tornado movement SARS spread,
crime, consumer behavior
Putting the geography into a computer
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Link between where and what

• In most of GIS, spatial objects are linked to
  attributes
• What about the link between where and when?

Representing in computer
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Multidisciplinary Science

• Geography
• Mathematics
• Remote Sensing
• Cartography
• Surveying
• Geodesy
• Statistics
• Computer Science
• Operations Research

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Spatial Component

• Almost everything that happens, happens
  somewhere.
• Estimates are that 80 of all data has a spatial
  component.
• Knowing where something happens is of critical
  importance to our daily life and others
• Data from most sciences can be analyzed
  spatially.

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Spatial Query
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The application of GIS is only limited by the
imagination of those who use it.

• Archaeology, agriculture, banking, defense and
  intelligence, electric and gas, engineering-
  pipeline, engineering- surveying, federal
  government, fire/EMS/disaster/homeland security,
  forestry, health and human services, insurance,
  education, landscape architecture, law
  enforcement and criminal justice, libraries and
  museums, location service, marine/cost/oceans,
  media, mining/earth science, natural resources,
  petroleum, real estate, retail business, state
  and local government, telecommunications,
  transportation, universities, and
  water/wasterwater

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Network solutions
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Ecosystem management
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3D mine with well data
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Environmental monitoring toxic plume
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Site location and client distance
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Modeling of future trends
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Components of GIS
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Components of GIS hardware

• Equipment needed to support the many activities
  of GIS ranging from data collection to data
  analysis
• Data acquisition surveying equipments, GPS
  receiver, remote sensing equipments, digitizer,
  scanner
• Data compilation/analysis workstation
• Data publishing web-server, mobile computing
  device

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Components of GIS software

• The definition of GIS by functionalities
• A system for capturing, storing, retrieving,
  manipulating, analyzing, and displaying data
  which are spatially referenced to the Earth
• So GIS software provides those functionalities

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Components of GIS data

• Core of GIS
• Kinds of geographic data are extensive
• Satellite image
• Maps
• Table
• Metadata data about data, documents
  characteristics of data
• Accounts for 70-80 of GIS projects in the early
  stage
• Impact of internet is huge geographic data is
  increasingly accessible to the general public

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What is special about GIS?
Integration

• Most problems exist in a geographic context. GIS
  puts various themes together.

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What is special about GIS?
Visualization

• Maps are worth a thousand words

• A map is worth a thousand word

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What is special about GIS?
Transformation

• Data raw facts, context-free
• Information interpretative facts
• Knowledge understand the reason by the knower
• GIS transform data into information and knowledge
  by integrating data of different kinds and sources

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GIS and geographic questions
Form process
How it looks the pattern of high job
accessibility concentrated along interstate
highway How it works the relationship between
job accessibility and transportation network

• How it looks? Form ? pattern
• How it works? Process ? prediction
• GIS can help you understand process by examining
  form

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GIS and geographic questions
General specific
Process of landslides can be understood better by
applying general rules to information derived
from layers at the local area

• General theory is important, but
  context-dependent idiosyncrasy is important also
• GIS analysis allows you to understand the world
  better by combining general knowledge with
  specific information