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Geographic Information Systems and Science: Enabling a Location-Based Technology

Geographic Information Systems and Science: Enabling a Location-Based Technology. Michael F. Goodchild University of California Santa Barbara. Geographic information. Information that links properties to positions on or near the Earth's surface the information of maps but much more besides

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Geographic Information Systems and Science: Enabling a Location-Based Technology

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  1. Geographic Information Systems and Science: Enabling a Location-Based Technology Michael F. Goodchild University of California Santa Barbara

  2. Geographic information • Information that links properties to positions on or near the Earth's surface • the information of maps • but much more besides • The atomic form • <x,z> • point observations, e.g. at weather stations • observations about lines, areas

  3. Three technologies • Earth measurement • the accurate determination of position on the Earth's surface

  4. Eratosthenes, 200 BC

  5. Perfect sphere, radius 6378 km Ellipsoid of rotation, flattening 1/300

  6. Ellipsoid Semi-major axis 1/flattening Airy 1830 6377563.396 299.3249646 Modified Airy 6377340.189 299.3249646 Australian National 6378160 298.25 Bessel 1841 (Namibia) 6377483.865 299.1528128 Bessel 1841 6377397.155 299.1528128 Clarke 1866 6378206.4 294.9786982 Clarke 1880 6378249.145 293.465 Everest (India 1830) 6377276.345 300.8017 Everest (Sabah and Sarawak) 6377298.556 300.8017 Everest (India 1956) 6377301.243 300.8017 Everest (Malaysia 1969) 6377295.664 300.8017 Everest (Malaysia, Singapore) 6377304.063 300.8017 Everest (Pakistan) 6377309.613 300.8017 Modified Fischer 1960 6378155 298.3 Helmert 1906 6378200 298.3 Hough 1960 6378270 297 Indonesian 1974 6378160 298.247 International 1924 6378388 297 Krassovsky 1940 6378245 298.3 GRS 80 6378137 298.257222101 South American 1969 6378160 298.25 WGS 72 6378135 298.26 WGS 84 6378137 298.257223563

  7. World Geodetic System of 1984 a = 6378137 m 1/f = 298.26 Clarke Ellipsoid of 1866 a = 6378206 m 1/f = 294.98

  8. The Global Positioning System

  9. Three technologies • Remote sensing • satellite-based • aircraft, drones

  10. Roofs versus roads • Road types • Major/minor roads • Vegetation cover • Shadows • Construction areas

  11. Three technologies • Geographic information systems • digital representation of geographic data • editing, transformation, analysis, modeling, visualization, decision support • virtually any conceivable task • The Canada Geographic Information System • 1966

  12. The geographic information industries • GPS industry • $1 billion • European Galileo • Data supply industry • remote sensing • NASA $10 billion • other US civilian agencies $10 billion • military and intelligence $30 billion • 500,000,000,000,000 sq m • petabytes of information online (1PB=1015 bytes)

  13. The geographic information industries • GIS software • desktop, Web, enterprise • $1 billion • ESRI 30% • Intergraph 20% • Location-based services • Web • cellphones

  14. Location-based services • Information services • provided by systems that know where they are • and modify information accordingly

  15. How does a system know where it is? • GPS onboard • cellphone • Triangulation from towers • Determined at system build time • IP address

  16. What kinds of information? • Nearby services • Visualization of invisible features • underground • around the corner • in the past • visually impaired user

  17. Location-based games • Played on location-enabled devices • cellphones

  18. New directions • Social sciences • most early applications were environmental • health, business, social services • Dynamics • from how the world looks to how the world works

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