Learn More
Today, there is a huge amount of data gathered about the Earth, not only from new spatial information systems, but also from new and more sophisticated data collection technologies. This scenario leads to a number of interesting research challenges, such as how to integrate geographic information of different kinds. The basic motivation of this paper is to(More)
Recent technological advances have made it possible to collect large amounts of 3D trajectory data. Such data play an essential role in numerous applications and are becoming increasingly important in mobile computing. One of the fundamental challenges in many of these application areas is the assessment of similarity between trajectories. As objects moving(More)
In this paper we address the problem of analyzing and managing complex dynamic scenes captured in video. We present an approach to summarize video datasets by analyzing the trajectories of objects within them. Our work is based on the identification of nodes in these trajectories as critical points that describe the behavior of an object over a video(More)
Carswell, J. (2002) Scale and orientation-invariant scene similarity metrics for image queries. ABSTRACT In this paper we extend our previous work on shape-based queries to support queries on configurations of image objects. Here we consider spatial reasoning, especially directional and metric object relationships. Existing models for spatial reasoning tend(More)
Spatiotemporal helixes are a novel way to model spatiotemporal change. They represent both the movement of an object, as it is expressed by the trajectory of its center, and the changes of its outline. Accordingly they are highly suitable to communicate the evolution of phenomena as they are captured e.g. in sequences of imagery. In this paper we present(More)
In spatiotemporal applications, meaningful changes vary according to object type, level of detail, and nature of application. In this paper, we introduce a dynamic classification scheme and its interaction with a spatiotemporal model, to describe change propagation in spatiotemporal queries. Our classification is based on identifying three levels of change,(More)
The assessment of the quality and accuracy of Volunteered Geographic Information (VGI) contributions, and by extension the ultimate utility of VGI data has fostered much debate within the geographic community. The limited research to date has been focused on VGI data of linear features and has shown that the error in the data is heterogeneously distributed.(More)