This book is the first collection of papers to address the problem of accuracy in spatial databases, and comprises papers drawn from a wide range of physical and human systems, taking approaches which vary from statistical to descriptive. Together they present both a comprehensive review of existing knowledge, techniques and experience, and an analysis of critical research needs in this area of spatial data handling. The papers selected in this book were originally presented in December 1988 in Montecito, California, at a meeting convened by the new US National Center for Geographic Information and Analysis (NCGIA), as the first of a series of initiatives to lay out a detailed agenda for activity in key problem areas in GIS.