This text constitutes the refereed conference proceedings of the 12th International Symposium, W2GIS 2013, held in Banff, Canada, in April 2013. The 11 revised full papers and 5 short papers presented were carefully selected from 28 submissions. The program covers a wide range of topics including spatial semantics and databases, location-based services and applications, trajectory representation and sensor web, spatial analysis and systems and map generation and modelling.

This book is about fossil plants of so-called 'pre-historic' angiosperms. It reflects the newest progress in research on the origin of angiosperms, and will definitely trigger many new ideas in research.