Geographical information systems are technological frameworks which are used to gather, analyze and manage data. It is an interdisciplinary field which draws on the principles of engineering, management, logistics, business and telecommunication. Geographical information system apps are tools which are used for storing and editing spatial and non-spatial data. These can also be used for analyzing spatial information, and sharing the results in the form of maps. Some of the important aspects of this discipline are data analysis, hydrological modeling, topological modeling, geometric networks, cartographic modeling, geostatistics, data mining and geocoding. Geographical information systems find extensive applications across various fields such as wildlife management, urban planning, sustainable development, archaeology, oceanography, economics, etc. Such selected concepts that redefine geographical information systems have been presented in this book. The topics covered in this extensive book deal with the core subjects of geographical information system. This book is meant for students who are looking for an elaborate reference text on geographical information systems.