Sensor, Observation, Sample, and Actuator (SOSA) Ontology
type: Ontology
type: Vocabulary
comment: This ontology is based on the SSN Ontology by the W3C Semantic Sensor Networks Incubator Group (SSN-XG), together with considerations from the W3C/OGC Spatial Data on the Web Working Group.
preferred namespace prefix: sosa

Actuation
type: Class
comment: An Actuation carries out an (Actuation) Procedure to change the state of the world using an Actuator.
example: The activity of automatically closing a window if the temperature in a room drops below 20 degree Celsius. The activity is the Actuation and the device that closes the window is the Actuator. The Procedure is the rule, plan, or specification that defines the conditions that triggers the Actuation, here a drop in temperature.

Actuator
type: Class
comment: A device that is used by, or implements, an (Actuation) Procedure that changes the state of the world.
example: A window actuator for automatic window control, i.e., opening or closing the window.

Feature Of Interest
type: Class
comment: The thing whose property is being estimated or calculated in the course of an Observation to arrive at a Result or whose property is being manipulated by an Actuator.
example: When measuring the height of a tree, the height is the ObservedProperty, 20m may be the Result of the Observation, and the tree is the FeatureOfInterest. A window is a FeatureOfInterest for an automatic window control Actuator.

Observable Property
type: Class
comment: An observable quality of a FeatureOfInterest.
example: The height of a tree, the depth of a water body, or the temperature of a surface are examples of observable properties, while the value of a classic car is not (directly) observable but asserted.

Actuatable Property
type: Class
comment: An actuatable property, i.e., characteristic, of a FeatureOfInterest.
example: A window actuator acts by changing the state between a frame and a window. The ability of the window to be opened and closed is its ActuatableProperty.

Observation
type: Class
comment: Activity of carrying out an (Observation) Procedure to estimate or calculate a value of a property of a FeatureOfInterest. Links to a Sensor to describe what made the Observation and how; links to an ObservableProperty to describe what the result is an estimate of, and to a FeatureOfInterest to detail what that property was associated with.
example: The activity of estimating the intensity of an Earthquake using the Mercalli intensity scale is an Observation as is measuring the moment magnitude, i.e., the energy released by said earthquake.

Platform
type: Class
comment: A Platform is an entity that hosts other entities, particularly Sensors, Actuators and other Platforms.
example: A post, buoy, vehicle, ship, aircraft, satellite, cell-phone, human or animal may act as platforms for (technical or biological) sensors or actuators.

Procedure
type: Class
comment: A workflow, protocol, plan, algorithm, or computational method specifying how to make an Observation, create a Sample, or make a change to the state of the world (via an Actuator). A Procedure is re-usable, and might be involved in many observations, samplings, or actuations. It explains the steps to be carried out to arrive at reproducible results.
example: The measured wind speed differs depending on the height of the sensor above the surface, e.g., due to friction. Consequently, procedures for measuring wind speed define a standard height for anemometers above ground, typically 10m for meteorological measures and 2m in Agrometeorology. This definition of height, sensor placement, and so forth are defined by the Procedure.
note: Many observations may be created via the same Procedure, the same way as many tables are assembled using the same instructions (as information objects, not their concrete realization).

Result
type: Class
comment: The Result of an Observation, Actuation, or act of Sampling. To store an observation's simple result value one can use the hasSimpleResult property.
example: The value 20 as the height of a certain tree together with the unit, e.g., Meter.

Sample
type: Class
comment: Feature on which Observations may be made, which is intended to be representative of a FeatureOfInterest that is not fully accessible.
comment: Physical samples are sometimes known as 'specimens'.
comment: A Sample is the result from an act of Sampling.
comment: Samples are artifacts of an observational strategy, and have no significant function outside of their role in the observation process. The characteristics of the samples themselves are of little interest, except perhaps to the manager of a sampling campaign. A Sample is intended to sample some FatureOfInterest in an application domain, so there is an expectation of at least one sampledFeature property. However, in some cases the identity, and even the exact type, of the sampled feature may not be known when observations are made using the sampling features.
example: A 'station' is essentially an identifiable locality where a sensor system or Process may be deployed and an observation made. In the context of the observation model, it connotes the 'world in the vicinity of the station', so the observed properties relate to the physical medium at the station, and not to any physical artifact such as a mooring, buoy, benchmark, monument, well, etc.
example: A statistical sample is often designed to be characteristic of an entire population, so that observations can be made regarding the sample that provide a good estimate of the properties of the population.
note: A transient sample, such as a ships-track or flight-line, might be identified and described, but is unlikely to be revisited exactly.

Sampler
type: Class
comment: A device that is used by, or implements, a Sampling Procedure to create or transform one or more samples.
example: A ball mill, diamond drill, hammer, hypodermic syringe and needle, image sensor or a soil auger can all act as sampling devices (i.e., be Samplers).

Sampling
type: Class
definition: An act of Sampling carries out a sampling Procedure to create or transform one or more samples.
example: Crushing a rock sample in a ball mill.
example: Digging a pit through a soil sequence.
example: Dividing a field site into quadrants.
example: Drawing blood from a patient.
example: Drilling an observation well.
example: Establishing a station for environmental monitoring.
example: Registering an image of the landscape.
example: Sieving a powder to separate the subset finer than 100-mesh.
example: Selecting a subset of a population.
example: Splitting a piece of drill-core to create two new samples.
example: Taking a diamond-drill core from a rock outcrop.

Sensor
type: Class
comment: Device, agent (including humans), or software (simulation) involved in, or implementing, a Procedure. Sensors respond to a stimulus, e.g., a change in the environment, or input data composed from the results of prior Observations, and generate a Result. Sensors can be mounted on Platforms.
definition: Device, agent (including humans), or software (simulation) involved in, or implementing, a (Sensing) Procedure. Sensors respond to a stimulus, e.g., a change in the environment, or input data composed from the results of prior Observations, and generate a Result. Sensors can be mounted on Platforms.
example: Accelerometers, gyroscopes, barometers, magnetometers, and so forth are sensors that are typically mounted on a modern smart phone (which acts as Platform). Other examples of sensors include the human eyes.

has feature of interest
type: ObjectProperty
domain includes: Observation
domain includes: Actuation
domain includes: Sampling
range includes: Feature Of Interest
range includes: Sample
comment: A relation between an Observation and the entity whose quality was observed, or between an Actuation and the entity whose property was modified, or between an act of Sampling and the entity that was sampled.
inverse of: is feature of interest of
example: For example, in an Observation of the weight of a person, the FeatureOfInterest is the person and the quality is weight.

has result
type: ObjectProperty
domain includes: Actuation
domain includes: Observation
domain includes: Sampling
range includes: Result
range includes: Sample
comment: Relation linking an Observation or Actuation or act of Sampling and a Result.
inverse of: is result of

has sample
type: ObjectProperty
domain includes: Feature Of Interest
range includes: Sample
comment: Relation between a FeatureOfInterest and the Sample used to represent it.
inverse of: is sample of

has simple result
type: DatatypeProperty
domain includes: Observation
domain includes: Actuation
comment: The simple value of an Observation or Actuation.
example: For instance, the values 23 or true.

is hosted by
type: ObjectProperty
domain includes: Actuator
domain includes: Sensor
domain includes: Sampler
range includes: Platform
comment: Relation between a Sensor, or Actuator, or Sampler and the Platform that it is mounted on or hosted by.
inverse of: hosts

hosts
type: ObjectProperty
domain includes: Platform
range includes: Actuator
range includes: Sensor
range includes: Sampler
comment: Relation between a Platform and a Sensor, or Actuator, or Sampler hosted or mounted on it.
inverse of: is hosted by

made by actuator
type: ObjectProperty
domain includes: Actuation
range includes: Actuator
comment: Relation linking an Actuation to the Actuator that made that Actuation.
inverse of: made actuation

made actuation
type: ObjectProperty
domain includes: Actuator
range includes: Actuation
comment: Relation between an Actuator and the Actuation it has made.
inverse of: made by actuator

is feature of interest of
type: ObjectProperty
domain includes: Feature Of Interest
range includes: Observation
range includes: Actuation
comment: A relation between a FeatureOfInterest and an Observation about it or an Actuation acting on it.
inverse of: has feature of interest

is observed by
type: ObjectProperty
domain includes: Observable Property
range includes: Sensor
comment: Relation between an ObservableProperty and the Sensor able to observe it.
inverse of: observes

is result of
type: ObjectProperty
domain includes: Result
domain includes: Sample
range includes: Actuation
range includes: Observation
range includes: Sampling
comment: Relation linking a Result to the Observation or Actuation that created or caused it.
inverse of: has result

is sample of
type: ObjectProperty
domain includes: Sample
range includes: Feature Of Interest
comment: Relation from a Sample to the FeatureOfInterest that it is intended to be representative of.
inverse of: has sample

made observation
type: ObjectProperty
domain includes: Sensor
range includes: Observation
comment: Relation between a Sensor and an Observation it has made.
inverse of: made by sensor

made by sensor
type: ObjectProperty
domain includes: Observation
range includes: Sensor
comment: Relation between an Observation and the Sensor which made the Observation.
inverse of: made observation

made by sampler
type: ObjectProperty
domain includes: Sampling
range includes: Sampler
comment: Relation linking an act of Sampling to the Sampler (sampling device or entity) that made it.
inverse of: made sampling

made sampling
type: ObjectProperty
domain includes: Sampler
range includes: Sampling
comment: Relation between a Sampler (sampling device or entity) and the Sampling act it performed.
inverse of: made by sampler

observed property
type: ObjectProperty
domain includes: Observation
range includes: Observable Property
comment: Relation linking an Observation to the property that was observed. The ObservableProperty should be a property of the FeatureOfInterest (linked by featureOfInterest) of this Observation.

acts on property
type: ObjectProperty
domain includes: Actuation
range includes: Actuatable Property
comment: Relation between an Actuation and the property of a FeatureOfInterest it is acting upon.
inverse of: is acted on by
example: In the activity (Actuation) of automatically closing a window if the temperature in a room drops below 20 degrees Celsius, the property on which the Actuator acts upon is the state of the window as it changes from being open to being closed.

is acted on by
type: ObjectProperty
domain includes: Actuatable Property
range includes: Actuation
comment: Relation between an ActuatableProperty of a FeatureOfInterest and an Actuation changing its state.
inverse of: acts on property
example: In the activity (Actuation) of automatically closing a window if the temperature in a room drops below 20 degrees Celsius, the property on which the Actuator acts upon is the state of the window as it changes from being open to being closed.

observes
type: ObjectProperty
domain includes: Sensor
range includes: Observable Property
comment: Relation between a Sensor and an ObservableProperty that it is capable of sensing.
inverse of: is observed by

phenomenon time
type: ObjectProperty
domain includes: Actuation
domain includes: Observation
domain includes: Sampling
range includes: TemporalEntity
comment: The time that the Result of an Observation, Actuation or Sampling applies to the FeatureOfInterest. Not necessarily the same as the resultTime. May be an Interval or an Instant, or some other compound TemporalEntity.

result time
type: DatatypeProperty
domain includes: Actuation
domain includes: Observation
domain includes: Sampling
comment: The result time is the instant of time when the Observation, Actuation or Sampling activity was completed.
range: dateTime

used procedure
type: ObjectProperty
domain includes: Actuation
domain includes: Observation
domain includes: Sampling
range includes: Procedure
comment: A relation to link to a re-usable Procedure used in making an Observation, an Actuation or taking a Sample typically through a Sensor, Actuator or Sampler.
definition: A relation to link to a re-usable Procedure used in making an Observation, an Actuation or taking a sample typically through a Sensor, Actuator or Sampler.