OGC API - Connected Systems is intended to act as a bridge between static data (geographic and other domain features) and dynamic data (observations of these feature properties, and commands/actuations that change these feature properties). “Part 1 — Feature Resources” defines resource types and encodings for providing metadata about systems and their deployments, as well as the procedures and sampling strategies used by these systems. Resource types defined in Part 1 are modeled on concepts from the Semantic Sensor Network Ontology (SOSA/SSN). “Part 2 — Dynamic Data” defines additional resource types and encodings that implement the SSN concepts needed for exchanging dynamic data related to the features defined in Part 1. It defines efficient ways of encoding this dynamic (time-varying) information (including observations, commands and system events), and mechanisms allowing bi-directional streaming of real-time data as well as access to historical data. Part 2 also defines a snapshot mechanism for dynamic feature properties.