GIS

We are happy to publish the papers selected for presentation at the 20th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems (ACM SIGSPATIAL GIS 2012) in these proceedings. ACM SIGSPATIAL GIS is the flagship event of SIGSPATIAL. In 2012, it was held in Redondo Beach, California, USA, from November 6 - 9. The conference is the premier annual gathering of researchers, developers, users, and practitioners from around the world who share interests in research and systems on spatial information processing. In particular, the conference fosters interdisciplinary discussions and research in Geographic Information Systems and Science (GIS) and provides a forum for original research contributions covering all conceptual, design, and implementation aspects of GIS and ranging from applications, user interface considerations, and visualization to storage management and indexing issues. This is the fifth year that the conference is being held under the auspices of the ACM SIGSPATIAL.