Applications of Geographic Data Examples of geographic data map data for vehicle navigation distribution network information for power,telephones,water supply,and sewage Vehicle navigation systems store information about roads and services for the use of drivers: Spatial data:e.g.,road/restaurant/gas-station coordinates Non-spatial data:e.g.,one-way streets,speed limits,traffic congestion Global Positioning System(GPS)unit-utilizes information broadcast from GPS satellites to find the current location of user with an accuracy of tens of meters. increasingly used in vehicle navigation systems as well as utility maintenance applications. Database System Concepts-6th Edition 25.17 @Silberschatz,Korth and Sudarshan
Database System Concepts - 6 25.17 ©Silberschatz, Korth and Sudarshan th Edition Applications of Geographic Data Examples of geographic data map data for vehicle navigation distribution network information for power, telephones, water supply, and sewage Vehicle navigation systems store information about roads and services for the use of drivers: Spatial data: e.g., road/restaurant/gas-station coordinates Non-spatial data: e.g., one-way streets, speed limits, traffic congestion Global Positioning System (GPS) unit - utilizes information broadcast from GPS satellites to find the current location of user with an accuracy of tens of meters. increasingly used in vehicle navigation systems as well as utility maintenance applications
Spatial Queries Nearness queries request objects that lie near a specified location. Nearest neighbor queries,given a point or an object,find the nearest object that satisfies given conditions. Region queries deal with spatial regions.e.g.,ask for objects that lie partially or fully inside a specified region. Queries that compute intersections or unions of regions. Spatial join of two spatial relations with the location playing the role of join attribute Database System Concepts-6th Edition 25.18 @Silberschatz,Korth and Sudarshan
Database System Concepts - 6 25.18 ©Silberschatz, Korth and Sudarshan th Edition Spatial Queries Nearness queries request objects that lie near a specified location. Nearest neighbor queries, given a point or an object, find the nearest object that satisfies given conditions. Region queries deal with spatial regions. e.g., ask for objects that lie partially or fully inside a specified region. Queries that compute intersections or unions of regions. Spatial join of two spatial relations with the location playing the role of join attribute