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ITIS 1210 Introduction to Web-Based Information Systems

ITIS 1210 Introduction to Web-Based Information Systems. Chapter 29 How Map Sites Work. Introduction. The Internet is not just about finding information It can be about finding directions as well Popular sites include Mapquest Older, maps & directions Google Earth

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ITIS 1210 Introduction to Web-Based Information Systems

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  1. ITIS 1210Introduction to Web-Based Information Systems Chapter 29 How Map Sites Work

  2. Introduction • The Internet is not just about finding information • It can be about finding directions as well • Popular sites include • Mapquest • Older, maps & directions • Google Earth • Also includes local information: hotels, restaurants, etc.

  3. Introduction • Map sites generally use information provided by commercial service • Updates sometimes accomplished by hiring people to drive the streets and make note of changes • Driving directions are important as well • Turn-by-turn • Shortest route • Fastest route • Cheapest gas enroute

  4. Introduction • Different interfaces used as well • Mapquest • HTML-based • Concentrates on directions and maps • Google Maps • More interactive • Different views (like satellite) • Better navigation

  5. How Map Sites Work • Navteq

  6. How Map Sites Work • Navteq • 600 researchers • Offices in 23 countries • Drive thru regions • Walk to Points of Interest • Gathers data • Stores it in a database • Used to update map sites regularly

  7. How Map Sites Work • When you request a map or driving directions • Your request is routed to a geocoding server • Converts address to latitude and longitude • Lat/long sent to a mapping server • Mapping server fetches map information and sends it to a routing server

  8. How Map Sites Work • Routing server’s job is to determine “best” router between starting and ending points • Algorithms consider • Length of segments • Expected average speed over each segment • “Cost” of the segment • Turns, stoplights, speed zones

  9. How Map Sites Work • Routing server quickly determines “best” route and delivers results: • Maps • Turn-by-turn directions • Expected time • Distance

  10. How Google Earth Works • Originally called Keyhole by a company named Earth Viewer • Gets photos from • Satellites • Aircraft • Kites • Hot air balloons

  11. How Google Earth Works • Aerial surveys • 15,000 to 30,000 feet • Height depends on resolution needed • Overlapping photographs • Permits removal of distortion caused by earth’s curvature • Film digitized at a high resolution • 1,800 dpi • Cleaned-up and color enhanced

  12. How Google Earth Works • Layers added …

  13. How Google Earth Works • To use you have to download and install (free) • Maps & data come from Google servers

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