This book focuses on the nature and characteristics of open source geospatial (OSG) software. The role of OSG approaches in spatial data handling is the cross-cutting theme of the book. Various sub-themes are explored that introduce readers unfamiliar to OSG software to the nature, purpose and applications of OS programming, and to the key new OS tools and their application within the geospatial data domain. The book also includes a discussion of new tools, approaches and applications for those already using OS approaches to software development.