The node descriptor file (at /osdl.js) is a JSON formatted string that describes the sensors and/or actuators provided by the node. The string contains four arrays: General, Sensors, Triggers and Actuators. The general array contains information that applies to all sensors,triggers and actuators on that node. The remaining arrays define zero or more interfaces of the sensors, triggers and actuators on that node. Control nodes do not define their own interfaces, instead interacting with the interfaces defined on other nodes.
General
A URL-keyed array of properties that are common to all sensors and actuators on the node. As an example the geographic location in latitude and longitude of the node is likely to apply also to all sensors and actuators of that node. The DarwinCore terms decimalLatitude and decimalLongitude could be used to describe the location of the sensor with the array keys in this instance being http://rs.tdwg.org/dwc/terms/decimalLatitude and http://rs.tdwg.org/dwc/terms/decimalLongitude respectively. The use of well established ontologies is recommended when this is possible.