SensorML 2.0 Examples

Metadata - Characteristics and Capabilities

Outside of the inputs, outputs, and parameters, characteristics and capabilities describe many of the properties that we might wish to know about a sensor, actuator, or process. These properties can be used for discovery but are often more important for understanding the nature of the object and for qualifying the output.

The distinction between the two might not always be clear, but in essence, capabilities provide property information that further clarify or qualify the output of the process (e.g. dynamic range, sensitivity, threshold, etc.), while characteristics provide useful properties that do not further qualify the output values (e.g. component dimensions, battery life operational limits, etc.).

As with most properties in SensorML, characteristics and capabilities utilize the concept of "soft-typing". That is, rather than trying to pre-define in schema every possible property that might be used to describe a a particular sensor or process, SensorML allows property types to be defined outside of the SensorML schema (typically within an online ontology) and then be used within a SensorML as a value to the definition attribute. The value of the definition attribute must be a resolvable URL that references an online property definition or single entry within an property ontology.

Characteristics and capabilities utilize SWE Common Data types for providing the name, semantics, units of measure (uom), value, and aggregation of the characteristics and capabilities. As becomes obvious in these examples, SWE Common Data is utilized extensively throughout SensorML as a means for defining properties and providing values. Under characteristics and capailities, properties can be listed as individual data components (Quantity, Category, Boolean, Text, Time, etc.) or can be grouped with related properties using DataRecord, DataArray, Matrix, Vector, etc.