Effective use of todays powerful GIS technology requires an understanding of the science of problem-solving that underpins it.  Since the first edition was published over a decade ago, this book has led the way, with its focus on the scientific principles that underpin GIS usage. It has also provided thorough, up-to-date coverage of GIS procedures, techniques and public policy applications.  This unique combination of science, technology and practical problem solving has made this book a best-seller across a broad spectrum of disciplines. This fully updated Third Edition continues to deliver on these strengths.