OGC's Sensor Model Language (SensorML), Sensor Observation Service (SOS), Observations and Measurements Schema (O&M), Web Alert/Notification Services (WAS/WNS), and Sensor Planning Service (SPS) are highlighted in a discussion of the Open GIS Consortium's (OGS's) effort to enable the sensor Web. The OGC concentrates on development of standards that enable discovery and exchange of sensor observations and the tasking of sensor systems. Functions targeted by OGC in a sensor Web are: discovery of sensors and sensor observations that meet the needs of the GIS community; determination of the abilities and quality of measurements of a sensor; accessibility to sensor parameters that automatically permit software to process and geolocation observations; retrieval of real-time or time series observations and coverages in standard encodings; tasking of sensors to acquire observations of interest; and subscription to and publishing of alerts sent by sensors or sensors services according to specific criteria. SensorML provided standard models and eXtensible Markup Language (XML) schema for describing sensor systems and will provide information needed to discover and locate sensor and sensor observations, process low-level observations, define interfaces, and list taskable properties. A hypothetical use case (consisting of a huge explosion with extensive burning of toxic materials) describes how, for instance, a sensor registry could be used to find that NASA already has an airborne sensor that can provide thermal imaging thru smoke and clouds and puts in a request through SPS. Notification would be received through WNS indicating that the task is approved and scheduled.