link from a requirement linked to an element in a UML model to an RDFS/OWL class or property which implements it
Battery
A Battery powering a System as its primary or secondary power source. As this is a specialization of the System class modeling of integrated battery management systems is also possible.
Material Sample
subset of a FeatureOfInterest that is physical (i.e., tangible)
A piece of rock, a blood sample, a water sample, etc.
MaterialSamples may be destroyed in connexion with the observation act or a subsequent preparation step.
MaterialSamples that are curated and preserved are sometimes known as 'specimens'.
Normal Operating Conditions
Type of observation or observation collection that describe the conditions under which a system is expected to operate normally.
Result
outcome of an Observation, Actuation, or act of Sampling. To store an observation's simple result value one can use the hasSimpleResult property.
The value 20 as the height of a certain tree together with the unit, e.g., Meter.
Spatial Sample
subset of a FeatureOfInterest defined by its location and shape in space When observations are made to estimate properties of a geospatial feature, particularly where the value of a property varies within the scope of the feature, a SpatialSample is used.
Some common names for spatial samples include: borehole, flightline, interval, lidar cloud, map horizon, microscope slide, mine level, mine, observation well, profile, quadrat, scene, section, ship track, spot, station, swath, trajectory, traverse, etc...
Depending on accessibility and on the nature of the expected property variation, a SpatialSample may extend in one, two or three spatial dimensions.
Statistical Sample
subset of a FeatureOfInterest defined by the statistical process used to create it
The male or female subset of a population.
StatisticalSamples usually apply to populations or other sets, of which a certain subset may be of specific interest.
Suboptimal Conditions
Type of observation or observation collection that describe the conditions under which a system is expected to operate sub-optimally. Results will still be reported but the performance of the sensor, in term of precision for example, will be impaired.
Survivable Conditions
Type of observation or observation collection that describe the conditions under which a system is expected to survive, that is to continue to exist in its current form, even if its future operations are impaired. A typical example is the temperature at which a sensor looses physical integrity and looses its shape. A system or sensor exposed to conditions outside of those reported by SurvivableConditions will no longer be serviceable.
end time
The value would usually be encoded using xsd:dateTime xsd:date xsd:gYearMonth xsd:gYear
instant of time when the Execution or Deployment was ended or completed
has operating conditions
Relation between a System and its Operating Conditions, modelled as ObservationCollection (or Observation) describing conditions under which the System can operate. A short but extensible list of sub-classes of OperatingConditions is provided in SSN-System, such as normal operating conditions, suboptimal conditions, and survivable conditions.
has simple result
relation from an Execution to its value expressed as a literal In the case of an Actuation, the result may be the value of the Property following the execution of the Procedure by the Actuator. In the case of an Observation, the result is the value of the Property produced by the execution of the Procedure by the Sensor.
For instance, the values 23 or true.
This DatatypeProperty provides an alternative to hasResult, to be used only if the execution result can be expressed as a Literal
has system capability
Relation between a System and an ObservationCollection (or Observation) describing the capability of the system. A sensor or system may have more than one set of system capabilities with different validity contexts.
has validity context
Links a an observation collection or observation (typically about the system capabilities) or a property (typically about the system capabilities) to its validity context, described as an observation collection or observation (typically about the system environment).
input value for execution
relation from an input value to an Execution that used it
is ultimate feature of interest of
relation from an ultimate FeatureOfInterest to an Execution, Execution Collection, or Deployment, for which it is the ultimate subject
made on platform
Relation between an Observation and the Platform the Sensor was attached to at the time the observation was made.
observation type
Information providing further detail on the type of Observations.
prepared sample
The Sample on which the PreparationProcedure is performed.
processing details
The PreparationProcedure used by the PreparationStep.
related sampling
Relation to an act of Sampling.
sample preparation step
A PreparationStep that uses the PreparationProcedure.
valid time
The time interval during which the result is assumed to be applicable for use.
result time
instant of time when the Execution was completed
start time
instant of time when the Execution or Deployment was initiated or tasked
W3C/OGC Spatial Data on the Web Working Group
Actuation classes and properties for the SSN Ontology.
Actuation classes and properties for the SSN Ontology. This module adds RDFS and OWL axioms to the terms defined in SOSA Actuation
SSN Ontology - actuation module
Sensor, Observation, Sample, and Actuator (SOSA) Ontology - actuation module
This ontology is based on the SOSA Ontology by the W3C/OGC Spatial Data on the Web Working Group, supplemented by some classes and properties required to implement ISO 19156:2023 , with axiomatization following SSN.
OMS Ontology - based on (SOSA) Ontology with SSN axiomatization
Vertical module adding SSN-style axioms to the SOSA-OMS module
link from an RDFS/OWL class or property to a requirement linked to an element in a UML model which it implements
feature has ultimate sample
relation from an ultimate FeatureOfInterest to a Sample or SampleCollection that is intended to be representative of it; i.e., the end of a chain of hasSample relations
has input
relation from a Procedure to an input required for its execution
This property will typically describe the type of the inputs required to execute the Procedure.
An input might be a calibration or conditioning parameter, or the output of a previous procedure within an extended processing chain.
has input value
assigns a value to an input defined by the Procedure that is used in an Execution
The input value MUST be consistent with a hasInput definition from the corresponding Procedure
The input might be a calibration or conditioning parameter, or the output of a previous procedure within an extended processing chain.
has output
relation from a Procedure to an output of its execution
This property will typically describe the type of the result from executing the Procedure.
has procedure
relation from a Property to a Procedure that can observe or act on it
has proxy
relation from an Property to a Stimulus that serves as its proxy
For example, the expansion of mercury is a Stimulus that serves as a proxy for some temperature Property. An increase or decrease in the velocity of spinning cups on a wind Sensor is serving as a proxy for the wind speed.
input for
relation from an input to a Procedure that uses it in an Execution
link from an Execution or Sample or Collection of these, to a collection that it is part of
Note that there is a single `member` property. OWL or SHACL constraints may limit the range depending on the context of different collection types
rules for the consistency of values of properties of collections and properties of their members are given for each collection type
is original sample of
relation from the initial Sample collected from the ultimate FeatureOfInterest to a downstream Sample or SampleCollection
made sampling has result
relation from a Sampler to a Sample or SampleCollection made by it
observation related to
relation from an Observation or ObservationCollection to another Execution or ExecutionCollection
This general relationship complements the specific predicates outbound from Observation. It is particularly useful to relate Observations (and collections) to other Executions (and collections)
has preparation step
Link to a preparation step used to prepare the sample
output for
relation from an output to a Procedure that generates it in an Execution
phenomenon occurred
result of an Execution that this time applies to
phenomenon time
time that the result of an Execution applies to the subject entity It may be an interval or an instant, or some other compound temporal entity [[!owl-time]].
The phenomenonTime is not necessarily the same as the resultTime. In the case of Actuation, phenomenonTime SHOULD indicate the time during which the actuator was active. In the case of Observation, the phenomenonTime MAY be distant from the resultTime. For example in the case of forecasts the phenomenonTime is after the resultTime. In historical, geological and cosmological investigations the phenomenonTime can be far in the past, while the resultTime is contemporary. In the case of Sampling the phenomenonTime SHOULD indicate the time during which the Sampling Procedure was active. The resultTime can indicate when the sample comes into the posession of the operator.
link from a quality description to an Observation or ObservationCollection that it relates to
related observation
relation from an Execution or ExecutionCollection to an Observation or ObservationCollection
This general relationship complements the specific predicates inbound to Observation. It is particularly useful to relate Observations (and collections) to other Executions (and collections)
relation from an Observation or ObservationCollection to some information pertaining to the quality of the result
The quality of a result can be assessed following the procedures in the ISO 19157 series.
dqv:hasQualityMeasurement from the Data Quality Vocabulary is equivalent
This instance-specific description complements the description of the observation Procedure, which provides information concerning the quality of all observations using this procedure. Multiple measures can be provided.
used for execution has result
relation from a Procedure to a Sample or SampleCollection made by it
Observation classes and properties for the SSN Ontology.
Sampling classes and properties for the SSN Ontology.
acts on
relation from an Actuator to a Property whose state may be changed by using it
In the activity (Actuation) of automatically closing a window if the temperature in a room drops below 20 degrees Celsius, the property upon which the Actuator acts is the state of the window as it changes from being open to being closed.
deployed on platform
relation from a Deployment to a Platform on which Systems are hosted
deployed system
relation from a Deployment to a deployed System
detects
relation from a Sensor to the Stimulus that it detects The Stimulus itself will be serving as a proxy for some Property.
has property
relation from an entity to a Property of that entity
has sample
relation from a FeatureOfInterest to the Sample or SampleCollection used to represent it
has subsystem
relation from a System to its component parts
hosts
relation from a Platform to an asset (System or Platform) hosted or mounted on it
is acted on by
relation from a Property to an Actuator that may change its state
is detected by
relation from a Stimulus to a Sensor that may detect it The Stimulus itself will be serving as a proxy for some Property.
is feature of interest of
relation from a FeatureOfInterest to an Execution, Execution Collection, or Deployment, operating on it i.e., to an Observation about it, to an Actuation acting on it, to an act of Sampling that sampled it, or to a Deployment for which it is the subject.
is hosted by
relation from an asset (System or Platform), to a Platform that it is mounted on or hosted by
is observed by
relation from a Property to a Sensor that is able to observe it
is property of
relation from a Property to a FeatureOfInterest that it is a quality of
is subsystem of
relation from a component System to a System that it belongs to
made actuation
relation from an Actuator to an Actuation or ActuationCollection it has made
made observation
relation from a Sensor to an Observation or ObservationCollection it has made
observes
relation from a Sensor to a Property that it is capable of sensing
originated
relation from a Stimulus to an Observation that was originated by it
property for
relation from a Property to some Procedure or System that acts on it or observes it
For example, from a Sensor to the properties it can observe; from an Actuator to the properties it can act on; from a SystemCapability to the Property the capability is described for.
used for execution
relation from a Procedure to an Execution or ExecutionCollection made using it
was acted on by
relation from a Property to an Actuation that changed its state
was observed by
relation from a Property to an Observation that observed it
was originated by
relation from an Observation to the Stimulus that originated it
acts on property
relation from an Actuation to the Property it acted upon
has original sample
relation from a Sample or SampleCollection to the initial Sample collected from the ultimate FeatureOfInterest
in deployment
relation from a Platform to a Deployment
For example, a relation between a buoy and a deployment of several Sensors.
is proxy for
relation from a Stimulus to the Property for which it is serving as a proxy
For example, the expansion of quicksilver is a stimulus that serves as a proxy for some temperature property. An increase or decrease in the velocity of spinning cups on a wind sensor is serving as a proxy for the wind speed.
is a result of made by sampler
relation from a Sample or SampleCollection to the Sampler that made it
is a result of used procedure
relation from a Sample or SampleCollection to the Procedure (plan) used to make it
has sampled feature
relation from a Sample or SampleCollection to the ultimate FeatureOfInterest that it is intended to be representative of; i.e., the end of a chain of isSampleOf relations
made by actuator
relation from an Actuation or ActuationCollection to the Actuator that made it
made by sensor or observer
relation from an Observation or ObservationCollection to the Sensor that made it
made sampling
relation from a Sampler to the Sampling or SamplingCollection it has made
observed property
relation from an Observation or ObservationCollection to the property that was observed
'observed property' covers the concepts referred to in [VIM] as 'measurand' (quantitative values) and 'examinand' (categorical and nominal values — [VIM4]), as well as complex and structured properties whose values may be represented as lists, vectors, arrays, rasters, geometries, etc. More specific terms are used in other contexts for related concepts, such as 'analyte' (chemistry) and 'determinand' (water quality).
Core classes and properties for the SSN Ontology. This module adds RDFS and OWL axioms to the terms defined in SOSA Core
SSN Ontology - core module
Operating Conditions
Type of observation or observation collection that describe operating conditions of systems. Sub-classes of this class explicit the desirability of the conditions. Three such sub-classes are provided as a basic classification: NormalOperatingConditions, SuboptimalOperatingConditions, and SurvivableConditions.
deployed asset
relation from a Deployment to an asset (System or Platform)
has deployment
relation from a System or Platform to a Deployment in which it is deployed
is sample of
relation from a Sample or SampleCollection to the FeatureOfInterest that it is intended to represent
made by sampler
relation from an act of Sampling to the Sampler that made it
Preparation Procedure
[ISO 19156:2023] A PreparationProcedure shall be defined as the description of preparation steps performed on a Sample
A workflow, protocol, plan, algorithm, or computational method specifying a step in preparing a Sample. A Preparation Procedure is re-usable, and might be involved in many preparations. It explains the steps to be carried out to arrive at reproducible results.
has result
relation from an Execution to its result In the case of an Actuation, the result may be the value of the Property following the execution of the Procedure by the Actuator. In the case of an Observation, the result is the value of the Property produced by the execution of the Procedure by the Sensor. In the case of a Sampling, the result is the Sample produced by the execution of the Procedure by the Sampler. An Execution has a single result, therefore sosa:hasResult is Functional.
The result value MUST be consistent with the hasOutput definition from the corresponding Procedure
has ultimate feature of interest
relation from a Deployment or Execution to its ultimate subject entity i.e., from an Actuation to the ultimate entity whose property was modified; from an Observation to the ultimate entity whose property was observed; from an act of Sampling to the ultimate entity that was sampled; or from a Deployment to its ultimate target
should match a property chain something like this but with sosa:isSampleOf* owl:propertyChainAxiom ( sosa:hasFeatureOfInterest sosa:isSampleOf )
This is useful when the proximate feature of interest is a sample of the ultimate feature of interest, directly or transitively.
implements
relation from a System to the Procedure that it is capable of executing
For example, the relationship between a sensor and the scientific measuring Procedure via which it senses.
made execution
relation from a System to an Execution or ExecutionCollection that it has made
madeExecution generalizes the madeActuation, madeObservation, and madeSampling properties. It is included in the ontology to support the definition of a common pattern for executions and their properties. madeExecution MUST be considered to be abstract, so SHOULD NOT appear in data instances. Applications can use concrete sub-properties of madeExecution.
Actuating Procedure
workflow, protocol, plan, algorithm, or computational method specifying how to make an Actuation An Actuating Procedure is re-usable, and might be applied in many Actuations. It explains the steps to be carried out to arrive at reproducible results.
Observing Procedure
[ISO 19156:2023] An ObservingProcedure shall be defined as the description of steps performed in order to determine the value of an observableProperty by an Observer.
workflow, protocol, plan, algorithm, or computational method specifying how to make an Observation An Observing Procedure is re-usable, and might be involved in many Observations. It explains the steps to be carried out to arrive at reproducible results.
A workflow, protocol, plan, algorithm, or computational method specifying how to make an observation; the description of the process used by an observer. This could be a chemical analysis method, a protocol for measuring an object, or even a checklist used by a human observer during a biodiversity campaign. The Procedure could further describe the algorithms behind simulators or models used to generate a result from other inputs.
[ISO 19156:2023] An instance of Procedure is a description of the process used by an observer. This could be a chemical analysis method, a protocol for measuring an object, or even a checklist used by a human observer during a biodiversity campaign. Procedure could further describe the algorithms behind simulators or models used to generate a result from other inputs.
for property
relation from some Procedure or System to a Property it acts on or observes
implemented by
relation from a Procedure to a System that is capable of executing it
For example, the relationship between a scientific measuring Procedure and a sensor that senses via that Procedure.
is result of
relation from a result to the Execution that created or caused it
made by system
relation from an Execution to the System that made it
madeBySystem generalizes the madeByActuator, madeBySensor, and madeBySampler properties. It is included in the ontology to support the definition of a common pattern for executions and their properties. madeBySystem MUST be considered to be abstract, so SHOULD NOT appear in data instances. Applications can use concrete sub-properties of madeBySystem.
Preparation Step
A PreparationStep is an individual step pertaining to a Sample PreparationProcedure.
link from a Collection to an Execution or Sample or Collection of these that is part of it
W3C/OGC Spatio-temporal Data on the Web Working Group
The System Capabilities Module imports SOSA and adds classes and properties required for the description of the operating conditions and capabilities of systems, particularly Sensors and Actuators.
Ontology of operating conditions and capabilities of systems
Please report any errors to the W3C Spatio-temporal Data on the Web Working Group via the SDW WG Public List public-sdw-wg@w3.org
Stimulus
event in the real world that triggers a Sensor
The properties associated to the Stimulus may be different to the eventual observed Property. It is the event, not the object, that triggers the Sensor.
Sampling Procedure
[ISO 19156:2023] A SamplingProcedure shall be defined as the description of steps performed by a Sampler in order to extract a Sample from its sampledFeature in the frame of a Sampling.
workflow, protocol, plan, algorithm, or computational method specifying how to make a Sampling A Sampling Procedure is re-usable, and might be involved in many Samplings. It explains the steps to be carried out to arrive at reproducible results.
spatial distribution of locations where to collect a sample (e.g., river segment) instrument (or mode of use thereof) required to collect a sample (e.g., fish net, electric stunner) field work instructions (e.g., dig four boreholes in each cardinal direction 2 metre way from the centre of the site; collect soil material from the 15-30 cm depth and mix it in a single bag)
has feature of interest
relation from an Execution or Deployment to its subject entity i.e., from an Actuation to the entity whose property was modified; from an Observation to the entity whose quality was observed; from an act of Sampling to the entity that was sampled; or from a Deployment to its target
For example, in an Observation of the weight of a person, the FeatureOfInterest is the person and the property is its weight.
This is the _proximate_ feature of interest, which may be a proxy entity such as a sample of the _ultimate_ feature of interest. Use `hasUltimateFeatureOfInterest` if the intention is to link to the _ultimate_ feature of interest.
used procedure
relation from an Execution or ExecutionCollection to a Procedure used to make it
This ontology is based on the SOSA Ontology by the W3C/OGC Spatial Data on the Web Working Group, supplemented by some classes and properties required to implement ISO 19156:2023 .
OMS Ontology - based on (SOSA) Ontology
The original source of each resource is indicated by the rdfs:isDefinedBy property
Platform or Host
entity that hosts other entities, particularly Systems and other Platforms
A post, buoy, vehicle, ship, aircraft, satellite, cell-phone, human or animal may act as platforms for (technical or biological) sensors or actuators. An environmental monitoring facility. A platform that hosts a set of sensors. A team performing a survey, where each team member would be modeled as an Observer.
The INSPIRE 'Environmental Monitoring Facility' may be implemented using SOSA by the OWL/RDFS class 'Platform'
Deployment
arrangement of one or more assets (Systems or Platforms) to execute Procedures with respect to designated features of interest.
A temperature Sensor deployed on a wall, a network of Sensors deployed for an Observation campaign.
A Deployment will usually be for a specified time interval. It MAY involve Platforms, or Systems, or both. A Deployment can be used quite flexibly to describe the use of systems, and platforms that host systems, with respect to a feature of interest.
Sample Collection
set of one or more Samples or SampleCollections; collections may be nested. All Sample properties may appear in a Sample Collection, including: hasOriginalSample , isSampleOfUltimateFOI , isSampleOf , isResultOfUsedProcedure , isResultOfMadeBySampler . If they are present, the value of these properties summarize the values of the matching properties of the member samples, where membership is either direct or transitive through one or more member sample collections. The following consistency rules apply with respect to the Sample properties listed above: 1. Where an individual Sample Collection omits a property, a member Sample (direct or transitive) MAY have any value for that property. 2. Where an individual Sample Collection has a single value for a property, each member Sample (direct or transitive) MUST have that same value for the property - i.e., the collection is homogeneous in that property. That property MAY be omitted in any member Sample or Sample Collection. 3. Where an individual Sample Collection has more than one value for a property, each member Sample (direct or transitive) MUST have a value for that property that matches one of the values for the property in the collection. 4. Where an individual Sample Collection has a value for a property that is a range or interval, each member Sample (direct or transitive) MUST have a value for that property that either matches or falls within that range or interval. 5. Where an individual Sample Collection has more than one value for a property that is a range or interval, each member Sample (direct or transitive) MUST have a value for that property that either matches or falls within one of those ranges or intervals.
The members of a collection do not necessarily share a common value for any property.
Procedure
workflow, protocol, plan, algorithm, or computational method specifying how to make an Execution A Procedure is re-usable, and might be applied in many Actuations, Observations, or Samplings. It explains the steps to be carried out to arrive at reproducible results.
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.
Procedure generalizes the ActuationProcedure, ObservationProcedure, and SamplingProcedure classes. It is included in the ontology to support the definition of a common pattern for executions and their properties.
Sampling Collection
set of one or more Samplings or SamplingCollections; collections may be nested All Sampling properties may appear in a Sampling Collection, including: hasFeatureOfInterest , hasUltimateFeatureOfInterest , madeBySampler , usedProcedure , hasInputValue , startTime , phenomenonTime , resultTime , hasResult . If they are present, the value of these properties summarize the values of the matching properties of the member samplings, where membership is either direct or transitive through one or more member sampling collections. The following consistency rules apply with respect to the Sampling properties listed above: 1. Where an individual Sampling Collection omits a property, a member Sampling (direct or transitive) MAY have any value for that property. 2. Where an individual Sampling Collection has a single value for a property, each member Sampling (direct or transitive) MUST have that same value for the property - i.e., the collection is homogeneous in that property. That property MAY then be omitted in any member Sampling or Sampling Collection. 3. Where an individual Sampling Collection has more than one value for a property, each member Sampling (direct or transitive) MUST have a value for that property that matches one of the values for the property in the collection. 4. Where an individual Sampling Collection has a value for a property that is a range or interval, each member Sampling (direct or transitive) MUST have a value for that property that matches or falls within that range or interval. 5. Where an individual Sampling Collection has more than one value for a property that is a range or interval, each member Sampling (direct or transitive) MUST have a value for that property that either matches or falls within one of those ranges or intervals.
Sampler
System that implements a SamplingProcedure to generate a Sample
A ball mill, diamond drill, hammer, hypodermic syringe and needle, image Sensor, or a soil auger can all act as Samplers. Sometimes, however, the distinction between the Sampler and the Sensor is not evident, if they are packaged as a unit.
A Sampler need not be a physical device.
Actuation
act of carrying out an ActuatingProcedure using an Actuator to change the value of an actuatable Property of a FeatureOfInterest In this context hasResult may indicate the value of the Property at the completion of the Actuation
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.
relatedObservation SHOULD be used to link to an associated Observation or ObservationCollection that monitors the actuated property to verify that the result value has been obtained.
An Actuation primarily concerns a single Property of a single FeatureOfInterest. Changes to multiple properties, or other combinations of Actuations, may be described in an ActuationCollection. Alternatively, applications may choose to encapsulate complexity by defining a complex property with multiple individual components, and a corresponding complex result (e.g., a vector). This approach is not prohibited by the SSN Ontology, but the details are beyond the scope of SSN.
Actuation Collection
set of one or more Actuations or ActuationCollections; collections may be nested All Actuation properties may appear in an Actuation Collection, including: hasFeatureOfInterest , usedProcedure , madeByActuator , actsOnProperty , endTime , hasResult , hasSimpleResult . If they are present, the value of these properties summarize the values of the matching properties of the member actuations, where membership is either direct or transitive through one or more member actuation collections. The following consistency rules apply with respect to the Actuation properties: 1. Where an individual Actuation Collection omits a property, a member Actuation (direct or transitive) MAY have any value for that property. 2. Where an individual Actuation Collection has a single value for a property, each member Actuation (direct or transitive) MUST have that same value for the property - i.e., the collection is homogeneous in that property. That property MAY then be omitted in any member Actuation or Actuation Collection. 3. Where an individual Actuation Collection has more than one value for a property, each member Actuation (direct or transitive) MUST have a value for that property that matches one of the values for the property in the collection. 4. Where an individual Actuation Collection has a value for a property that is a range or interval, each member Actuation (direct or transitive) MUST have a value for that property that matches or falls within that range or interval. 5. Where an individual Actuation Collection has more than one value for a property that is a range or interval, each member Actuation (direct or transitive) MUST have a value for that property that either matches or falls within one of those ranges or intervals.
Actuator
System that implements an ActuatingProcedure to change the value of an actuatable Property This may be a device, a piece of infrastructure, an agent (including humans), or software (simulation).
A window actuator for automatic window control, i.e., opening or closing the window.
Property
identifiable quality of features of interest that can be observed or acted upon A property can apply to different features of interest.
Cars (a feature type) all have a characteristic colour, where 'colour' is a property.
Concepts from existing code lists, vocabularies, and taxonomies, may be used as instances of Property
Sampling
act of carrying out a SamplingProcedure using a Sampler to create one or more Samples of a FeatureOfInterest
Crushing a rock sample in a ball mill.
Digging a pit through a soil sequence.
Dividing a field site into quadrants.
Drawing blood from a patient.
Drilling an observation well.
Establishing a station for environmental monitoring.
Registering an image of the landscape.
Selecting a subset of a population.
Sieving a powder to separate the subset finer than 100-mesh.
Splitting a piece of drill-core to create two new samples.
Taking a diamond-drill core from a rock outcrop.
Sensor or Observer
Observer
System that implements an ObservingProcedure to determine the value of an observable Property This may be a device, a piece of infrastructure, an agent (including humans), or software (simulation). A Sensor responds to a stimulus, e.g., a change in the environment, or input data composed from the results of prior Observations.
Accelerometers, gyroscopes, barometers, magnetometers, and so forth are Sensors that are typically mounted on a modern smartphone (which acts as Host or Platform). Other examples of Sensors include the human eyes.
The UML class 'Observer' from ISO 19156:2023 is implemented in SOSA by the OWL/RDFS class 'Sensor'. The class name 'Sensor' is preferred for backward compatibility with existing SOSA deployments.
Sensor
Execution of a Procedure
act of carrying out a Procedure using a System
Execution generalizes the Actuation, Observation, and Sampling classes. It is included in the ontology to support the definition of a common pattern for executions and their properties. Execution MUST be considered to be abstract, so any individual Execution SHOULD be declared to be an instance of one of the concrete sub-classes, and not of the Execution class.
Execution Collection
set of one or more Executions or ExecutionCollections; collections may be nested All Execution properties may appear in an Execution Collection, including: hasFeatureOfInterest , usedProcedure , madeBySystem , endTime, resultTime , startTime . If they are present, the value of these properties summarize the values of the matching properties of the member Executions, where membership is either direct or transitive through one or more member execution collections. The following consistency rules apply with respect to the execution properties listed above: 1. Where an individual Execution Collection omits a property, a member Execution (direct or transitive) MAY have any value for that property. 2. Where an individual Execution Collection has a single value for a property, each member Execution (direct or transitive) MUST have that same value for the property - i.e., the collection is homogeneous in that property. That property MAY then be omitted in any member Execution or Execution Collection. 3. Where an individual Execution Collection has more than one value for a property, each member Execution (direct or transitive) MUST have a value for that property that matches one of the values for the property in the collection. 4. Where an individual Execution Collection has a value for a property that is a range or interval, each member Execution (direct or transitive) MUST have a value for that property that matches or falls within that range or interval. 5. Where an individual Execution Collection has more than one value for a property that is a range or interval, each member Execution (direct or transitive) MUST have a value for that property that either matches or falls within one of those ranges or intervals.
Execution Collection generalizes the Actuation Collection, Observation Collection, and Sampling Collection classes. It is included in the ontology to support the definition of a common pattern for executions and their properties. Execution Collection MUST be considered to be abstract, so any individual Execution Collection SHOULD be declared to be an instance of one of the concrete sub-classes, and not of the Execution Collection class.
Feature Of Interest
entity that is the target of an Execution or Deployment i.e., whose property is being estimated by an Observation, or whose property is being manipulated by an Actuator, or which is being sampled or transformed in an act of Sampling, or which is the target of Executions planned as part of a Deployment.
When measuring the height of a tree, the height is the observed Property, 20m may be the Result of the Observation, and the tree is the FeatureOfInterest. A window is a FeatureOfInterest for an automatic window control Actuation.
System
entity that implements a Procedure in the context of an Execution
This may be a device, a piece of infrastructure, an agent (including humans), or software (simulation). Different Systems can implement the same (reusable) Procedure for different Executions. A System may have components, its sub-systems, which are other systems.
Specific system types may be implemented as sub-classes of this class or its sub-classes. Their descriptions may capture the properties and characteristics of a whole class of systems, corresponding with the information typically found in a data-sheet. Individual system instances are members of this class or its sub-classes.
System generalizes the Actuator, Sensor, and Sampler classes. It is included in the ontology to support the definition of a common pattern for executions and their properties. System MUST be considered to be abstract, so any individual System SHOULD be declared to be an instance of a concrete sub-class, and not of the System class.
The association of a System (Actuator, Sensor, and Sampler) with a FeatureOfInterest is usually in the context of an Execution or a Deployment. A System can be hosted by a Platform. A System can be deployed for a specified time interval as part of a Deployment.
Sample
piece or subset that is intended to be representative of a FeatureOfInterest
A 'station' is a spatial sample, in the form of an identifiable locality where a sensor system or Procedure 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.
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.
Samples are typically subsets or extracts from an entity or feature. Every sample is expected to (eventually) be the feature of interest of an Observation. Samples are used in situations where observations cannot be made directly on the ultimate feature of interest, either because the entire feature cannot be observed, or because it is more convenient to use a proxy. Samples are thus 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, so there is an expectation of at least one isSampleOf 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 sample. Physical samples are sometimes known as 'specimens'. A transient sample, such as a ships-track or flight-line, might be identified and described, but is unlikely to be revisited exactly.
Observation Collection
set of one or more Observations or ObservationCollections; collections may be nested All Observation properties may appear in an Observation Collection, including: hasFeatureOfInterest , hasUltimateFeatureOfInterest , usedProcedure , madeBySensor , observedProperty , phenomenonTime , startTime, resultTime , hasResult , hasSimpleResult : If they are present, the value of these properties summarize the values of the matching properties of the member observations, where membership is either direct or transitive through one or more member observation collections. The following consistency rules apply with respect to the Observation properties listed above: 1. Where an individual Observation Collection omits a property, a member Observation (direct or transitive) MAY have any value for that property. 2. Where an individual Observation Collection has a single value for a property, each member Observation(direct or transitive) MUST have that same value for the property - i.e., the collection is homogeneous in that property. That property MAY then be omitted in any member Observation or Observation Collection. 3. Where an individual Observation Collection has more than one value for a property, each member Observation (direct or transitive) MUST have a value for that property that matches one of the values for the property in the collection. 4. Where an individual Observation Collection has a value for a property that is a range or interval, each member Observation (direct or transitive) MUST have a value for that property that matches or falls within that range or interval. 5. Where an individual Observation Collection has more than one value for a property that is a range or interval, each member Observation (direct or transitive) MUST have a value for that property that either matches or falls within one of those ranges or intervals.
The results of collections of observations are often packaged in a 'data cube' whose axes define the range of properties of the set of observations.
An instance of ObservationCollection represents a container for a set of data derived from observations. This broadly corresponds with the class Dataset from DCAT.
Observation
act of carrying out an ObservingProcedure using a Sensor to estimate or calculate a value of an observable Property of a FeatureOfInterest
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.
When the feature of interest cannot be observed directly, a sample of it might be used in Observations as a proxy for it. In such case, the Sample is the proximate Feature of Interest of the Observation, while the (ultimate) Feature of Interest of the act of Sampling (i.e., the entity that the Sample is ultimately 'isSampleOf') is the ultimate Feature of Interest of the Observation.
An Observation primarily concerns a single Property of a single FeatureOfInterest. Observations of multiple properties, or other combinations of Observations, may be described in an ObservationCollection. Alternatively, applications may choose to encapsulate complexity by defining a complex property with multiple individual components, and a corresponding complex result (e.g., a vector). This approach is not prohibited by the SSN Ontology, but the details are beyond the scope of SSN.
Core classes and properties for the SSN Ontology.
Sensor, Observation, Sample, and Actuator (SOSA) Ontology - core module