Monitoring Spatially Referenced Entities in Wireless Sensor Networks

Wireless sensor networks (WSNs) make it possible to gather information about the physical world in novel ways and in unprecedented levels of detail. In the environmental sciences, in particular, WSNs are on the way to becoming an important tool for monitoring spatially- and temporally-extended physical phenomena. However, support for high-level and expressive spatio-analytic tasks to explore relationships between spatially referenced entities (e.g., whether mist is over a vineyard or has not yet touched it) and to derive representations grounded on such relationships (e.g., the geometrical extent of that part of a vineyard that is covered by mist) is still incipient, particularly in the case of in-network processing approaches that are imperative, due to energy scarcity, in mote-level WSNs. This paper describes distributed implementations of a comprehensive collection of spatio-algebraic operations that enable the expression and evaluation of tasks involving spatial predicates as well as the derivation of new geometries from existing geometries. This makes it possible to report back only fine-grained information.