This book is mainly focused on two themes: transportation and smart city applications. Open geospatial science and technology is an increasingly important paradigm that offers the opportunity to promote the democratization of geographical information, the transparency of governments and institutions, as well as social, economic and urban opportunities. During the past decade, developments in the area of open geospatial data have greatly increased. The open source GIS research community believes that combining free and open software, open data, as well as open standards, leads to the creation of a sustainable ecosystem for accelerating new discoveries to help solve global cross-disciplinary urban challenges. The vision of this book is to enrich the existing literature on this topic, and act one step towards more sustainable cities through employment of open source GIS solutions that are reproducible. Various contributions are provided and practically implemented in several urban use cases. Therefore, apart from researchers, lecturers and students in the geography/urbanism domain, crowdsourcing and VGI domain, as well as open source GIS domain, it is believed the specialists and mentors in municipalities and urban planning departments as well as professionals in private companies would be interested to read this book.