Heywood, D. Ian. An introduction to geographical information systems / Ian Heywood, Sarah Cornelius, and Steve Carver. - 2nd ed. - Harlow, England ; New York : Prentice Hall, 2002. - xv, 295 p. : ill. (some col.), col. maps ; 25 cm. Includes bibliographical references (p. 267-281). ISBN: 0130611980 LCCN: Subjects--Topical Terms: Geographic information systems. Dewey Class. No.: 910.285 HEY