Sensor web is a type of sensor network that heavily utilizes the World Wide Web and is especially suited for environmental monitoring. OGC's Sensor Web Enablement (SWE) framework defines a suite of web service interfaces and communication protocols abstracting from the heterogeneity of sensor (network) communication. Definition The term "sensor web" was first used by Kevin Delin of NASA in 1997, to describe a novel wireless sensor network architecture where the individual pieces could act and coordinate as a whole. In this sense, the term describes a specific type of sensor network: an amorphous network of spatially distributed sensor platforms (pods) that wirelessly communicate with each other. This amorphous architecture is unique since it is both synchronous and router-free, making it distinct from the more typical TCP/IP-like network schemes. A pod as a physical platform for a sensor can be orbital or terrestrial, fixed or mobile and might even have real time accessibility via the Internet. Pod-to-pod communication is both omni-directional and bi-directional where each pod sends out collected data to every other pod in the network. Hence, the architecture allows every pod to know what is going on with every other pod throughout the sensor web at each measurement cycle. The individual pods (nodes) were all hardware equivalent and Delin's architecture did not require special gateways or routing to have each of the individual pieces communicate with one another or with an end user. Delin's definition of a sensor web was an autonomous, stand-alone, sensing entity – capable of interpreting and reacting to the data measured – that does not necessarily require the presence of the World Wide Web to function. As a result, on-the-fly data fusion, such as false-positive identification and plume tracking, can occur within the sensor web itself and the system subsequently reacts as a coordinated, collective whole to the incoming data stream. For example, instead of having uncoordinated smoke detectors, a sensor web can react as a single, spatially dispersed, fire locator. The term "sensor web" has also morphed into sometimes being associated with an additional layer connecting sensors to the World Wide Web. The Sensor Web Enablement (SWE) initiative of the Open Geospatial Consortium (OGC) defines service interfaces which enable an interoperable usage of sensor resources by enabling their discovery, access, tasking, as well as eventing and alerting. By defining standardized service interfaces, a sensor web based on SWE services hides the heterogeneity of