... August 20 01, another El Niño event, not so extreme as the 19 97 event, is forecasted to occur at the end of the year 20 01 N.D Bình 2 /16 7 Chapter An introduction to GIS ERS 12 0: Principles of Geographic ... integrity and system crash recovery, and they have a high-level, N.D Bình 10 /16 7 Chapter An introduction to GIS ERS 12 0: Principles of Geographic Information Systems easy to use data manipulation language ... data entry, data analysis and data presentation N.D Bình 11 /16 7 Chapter An introduction to GIS ERS 12 0: Principles of Geographic Information Systems Representations are models of real world phenomena...