ABSTRACT

Second, traces of human activity and crowd-sourcing efforts facilitated by the Internet. The proliferation of cost-effective and ubiquitous positioning technologies, mobile devices, and sensors have enabled us to collect massive amounts of spatial information of human and wildlife activity. For example, FourthSquare-a popular local search and discovery service-allow users to check-in at more than 60 million venues, and so far has more than 6 billion check-ins [2]. Driven by the business potential, more and more businesses are providing services that are location-aware. At the same time, the Internet has made remote collaboration so easy that, now, a crowd can even generate a free mapping of the world autonomously. OpenStreetMap [3] is a large collaborative mapping project, which is generated by users around the globe, and it has more than two million registered users as of this writing.