Geographic Information Science and Systems LONGLEY, PAUL A. (UNIVERSITY COLLEGE LONDON, UK),GOODCHILD, MICHAEL F. (UNIVERSITY OF CALIFORNIA AT SANTA BARBARA, USA),MAGUIRE, DAVID J. (ENVIRONMENTAL SYSTEMS RESEARCH INSTITUTE, INC. (ESRI), REDLANDS, CA, USA),RHIND, DAVID W. (CITY UNIVERSITY, LONDON, UK)