Entity Overview
This document provides a high-level overview of the different RDF entity types used in the SDL and how they relate through composition, ontology alignment, and Linked Data Platform (LDP) containers.
The SDL does not use a rigid class hierarchy. Instead, it enables compositional modeling by assigning multiple rdf:type values to describe the role and structure of each resource.
Core Concepts
rdf:type
Each entity in SDL can declare multiple RDF types to reflect its functional role in the system.
LDP Containers
Entities are managed within LDP containers that determine how they are listed, created, and related to one another (Basic, Direct, Indirect).
Composition by rdf:type
SDL Entities often combine types from different vocabularies to model their structure and behavior. For example:
Example: A file representing a sensor result
ex:observation1
a sosa:Observation , prov:Entity , dcat:Distribution ;
dct:title "Soil Gas Measurement" ;
sosa:madeBySensor ex:li8250 ;
dcat:downloadURL <https://example.org/data/soil.csv> .
This shows that:
- The entity is a measurement (sosa:Observation)
- It is data that can be traced in provenance (prov:Entity)
- It is downloadable (dcat:Distribution)
Relationships
Entities in SDL are linked via named properties from the source ontologies:
- dcat:dataset links dcat:Catalog → dcat:Dataset
- dcat:distribution links dcat:Dataset → dcat:Distribution
- prov:wasGeneratedBy links prov:Entity → prov:Activity
- sosa:hasResult or sosa:hasSimpleResult asociates observations with values
- ssn:deployedSystem links ssn:Deployment → ssn:System
RDF Classes in SDL
| RDF Class | Namespace | Description | Documentation |
|---|---|---|---|
| dcat:Catalog | DCAT | A container resource that holds datasets | dcat:Catalog |
| dcat:Dataset | DCAT | A metadata-described scientific dataset | dcat:Dataset |
| dcat:Distribution | DCAT | A downloadable representation of a dataset | dcat:Distribution |
| dcat:Resource | DCAT | A general-purpose superclass for all cataloged resources | dcat:Resource |
| prov:Activity | PROV-O | An event or process that generates or uses entities | prov:Activity |
| prov:Agent | PROV-O | A person, system, or organization involved in a provenance chain | prov:Agent |
| prov:Entity | PROV-O | A piece of data or recordable object with provenance | prov:Entity |
| sosa:FeatureOfInterest | SOSA | The entity whose properties are being observed or measured | sosa:FeatureOfInterest |
| sosa:ObservableProperty | SOSA | The property observed during an Observation | sosa:ObservableProperty |
| sosa:Observation | SOSA | An act of observing or measuring a property of a feature | sosa:Observation |
| sosa:Platform | SOSA | A structure or system that hosts sensors or samplers | sosa:Platform |
| sosa:Result | SOSA | The outcome or value produced by an observation, sampling, or actuation | sosa:Result |
| sosa:Sample | SOSA | A physical or digital subset of a feature of interest used in observations | sosa:Sample |
| sosa:Sampling | SOSA | The act of producing a sample from a feature of interest | sosa:Sampling |
| sosa:Sampler | SOSA | A device, software, or agent capable of performing a sampling activity | sosa:Sampler |
| ssn:Deployment | SSN | The deployment of a system into a specific context or environment | ssn:Deployment |
| ssn:Property | SSN | An observable or measurable characteristic of a real-world feature | ssn:Property |
| ssn:System | SSN | A sensing or measurement system that performs observations | ssn:System |
This modular, compositional approach enables reuse across scientific domains, supporting complex workflows and data stages through shared semantics.