week 1 & 2 notes

• Geographic Information System (GIS)


  A decision support system comprising of computer hardware, software, geographic data, and personnel designed to efficiently capture, store, manipulate, analyse and display all forms of spatial and non-spatial (attribute) data for better management of geographical area

  
• Geographic Information System (GIS)


  An organized collection of computer hardware, software, geographic data, and personnel designed to efficiently capture, store, update, manipulate, analyze, and display all forms of geographically referenced information

  
• GIS represents a rapidly developing field lying at the intersection of many disciplines namely, cartography, computing, geography, earth & natural sciences, statistics, surveying and other disciplines concerned with handling and analyzing spatial and non-spatial referenced data

  
• GIS is a special-purpose digital database in which a common spatial coordinate system is the primary means of reference

  
• Components of GIS


  • Computer hardware
  • Sets of application software modules
  • Proper organizational context

  
• Computer hardware


  • Main computer system or central processing unit (CPU)
  • Peripherals: terminal, digitizer/scanner, disk drive, tape drive, plotter, printer
• Software modules


  • Data input, editing and verification
  • Data storage and database management
  • Data analysis, modeling and cartographic manipulation
  • Data output and presentation
  • User interface/interaction
• Data input, editing and verification

  Data transformation, format conversion, error detection and editing, edge matching and registration
• Data storage and database management


  • Effective data storage, retrieval and updating facilities
  • Multi-user environment
  • Data independence, security and integrity
• Data analysis, modeling and cartographic manipulation


  Map overlaying, reclassification procedures, proximity analysis, buffering & corridoring techniques, network analysis and other cartographic modeling tools
• Data output and presentation

  Displaying data as maps, tables, and figures (graphs and charts)
• User interface/interaction


  English-like command languages and interactive ways of command entry
• GIS is following in the steps of pioneers who developed paper maps that integrated all manner of different types of data for analysis

  
• Examples of historic use of multiple-theme maps

  • Maps of the Battle of Yorktown drawn by the French Cartographer Louis-Alexandre Berthier with hinged overlays to show troop movements
  • The mid-19th Century "Atlas to Accompany the Second Report of the Irish Railway Commissioners" showing population, traffic flow, geology and topography superimposed on the same base map
  • Dr. John Snow's map showing the locations of deaths by cholera in central London in September, 1854 to track the source of the outbreak
• Multiple-Theme Maps


  Characteristic of GIS - ability to integrate different types of data and analyze it as a whole

  
• GIS is following in the steps of pioneers who developed paper maps that integrated all manner of different types of data for analysis</b>

  
• Examples of early multiple-theme maps

  • Maps of the Battle of Yorktown with hinged overlays to show troop movements
  • Mid-19th Century "Atlas to Accompany the Second Report of the Irish Railway Commissioners" showing population, traffic flow, geology and topography
  • Dr. John Snow's map showing locations of deaths by cholera in central London in 1854
  • Map of Napoleon's attempted conquest of Russia integrating troop movements with dates, times, troop numbers, weather and related data
• Ian McHarg


  • Discussed the use of selection of specific data from maps, the use of overlays, and most of the basic techniques used in common GIS query and analysis

  
• Ian McHarg's methods were very labor-intensive, but at this time computers were starting to be used for things other than rocket science and payrolls, and we were about to witness ''The Quantitative Revolution' in Geography'
• Quantitative geography


  Developed as statistical and computational tools became capable of handling the large amounts of data common in geographical data sets
• Factors causing changes in quantitative geography

  • Developments in computer technology - improvements in hardware, esp. graphics
  • Development of theories of spatial processes in economic and social geography, anthropology, and regional science
  • Increasing social awareness, education levels and mobility, together with a growing awareness of environmental problems
  • Rapid increases in the ability to collect mapping data, but limitations in the speed of map production
• The growing need for better information to help manage a rapidly changing Earth led to a need for integrated information, generally with a spatial component common to all the data
• Examples of integrated information with a spatial component


  • Integrated transportation plans developed for Chicago and Detroit in the 1950s and 1960s requiring the integration of highly varied transportation data: routes, destinations, origins, and times
• Department of Geography at the University of Washington in Seattle


  • Conducted research on advanced statistical methods, rudimentary computer programming for geographical analysis and computer cartography, being most active in the period 1958-61
• Notable people and their major fields of interest from the University of Washington group

  • Nystuen - fundamental spatial concepts - distance, orientation, connectivity
  • Tobler - computer algorithms for map projections and computer cartography
  • Bunge - theoretical geography - geometric basis for geography: points, lines and areas
  • Berry - Geographical Matrix of places by characteristics (attributes) - regional studies by overlaying maps of different themes - systematic studies by detailed evaluation of a single layer/map
• Raster GIS


  Stores spatial data based on a grid for location

  
• Berry's Geographical Matrix lent itself to a raster representation
• Example of a raster map


  • Vegetation cover map using a raster GIS named macGIS

  
• Canada Geographic Information System (CGIS)

  One of the earliest GIS developed, started in the mid 1960s, designed as a large scale system and still operating today (although in a somewhat revised form)

  
• Purpose of CGIS


  • To analyze the data collected by the Canada Land Inventory (CLI) and to produce statistics to be used in developing land management plans for efficient land use over large areas of rural Canada
• Maps created by the Canada Land Inventory (CLI)

  • Soil capability for agriculture
  • Recreation capability
  • Capability for wildlife (ungulates)
  • Capability for wildlife (waterfowl)
  • Forestry capability
  • Present land use
  • Shoreline
• The initial perception was that computers could perform a range of analyses once the data had been input, which was the driving idea behind setting up the CGIS system
• CGIS, being one of the first large GIS, required the development of a lot of new technology
• CGIS had very high costs of technical development since much of the system had to be invented as it was built, leading to major cost over-runs and the analysis phase keeping slipping behind schedule
• By 1970, the CGIS project was in trouble with significant failures to deliver promised tabulations of data and the analysis capabilities still in the development stages
• CGIS was still highly regarded in late 1970s and early 1980s as a centre of technological excellence, despite the aging of database
• Key innovative ideas in CGIS

  • Use of scanning for input of high density area objects
  • Use of absolute system of co-ordinates for entire country with precision adjustable to resolution of data
  • Coding of area object boundaries by arc, with pointers to left and right area objects
  • Separation of data into attribute and locational files: 'descriptor dataset' (DDS) and 'image dataset' (IDS)
  • Concept of an attribute table
  • Implementation of functions for polygon overlay, measurement of area, user-defined circles and polygons for query
• Roger Tomlinson


  • One of the two people credited with inventing the name 'GIS' (the other was Prof. Duane Marble)
• Harvard Laboratory for Computer Graphics and Spatial Analysis

  Created when Howard Fisher moved from Chicago to Harvard to establish the lab in the mid-1960s, with the initial purpose of developing general-purpose mapping software
• Harvard Lab Packages


  • SYMAP (1964)
  • CALFORM (late 1960s)
  • SYMVU (late 1960s)
  • GRID (late 1960s)
  • POLYVRT (early 1970s)
  • ODYSSEY (mid 1970s)