Introduction to SensorThingsAPI data model
The OGC SensorThings API was originally designed to be an API for exchanging observational data in the IoT domain, but it quickly shown itself to be a full successor to the OGC Sensor Observation Service. The SensorThings API in short:
- A standard for exchanging sensor data and metadata
- Historic data & current data
- RESTful + JSON Encoded, with a powerful querying mechanism (based on OASIS OData)
- Supporting ISO MQTT messaging
- Easy to use & understandable: Discoverable with just a web browser
Here is a diagram showing the different classes from OGC SensorThings API Part 1: Sensing Version 1.1
For those who are familiar with ISO 19156 (aka OGC OMS), you will find those data models have a lot in common.
The main class to consider is the Observation that provides the result that was obtained at a specific date, location, following a particular procedure. The ObservedProperty, Sensor, Thing and FeatureOfInterest enable the contextualization of those parameters.
The main difference with OMS relies in the fact that STA introduces the Datastream concept as a way to group observations that "come together".
This is very common with repeated measurements like time series, or measurements made along a trajectory. The Datastream enables grouping those observations and avoids repeating parameters that remain unchanged like the Sensor or Observed Property.
This concept is explained further in this video: https://www.youtube.com/watch?v=bYDSgs2fKLk
Further documentation of the OGC SensorThings API:
- The specification of version 1.1: https://docs.ogc.org/is/18-088/18-088.html
- The GitHub page: https://github.com/opengeospatial/sensorthings
- Tutorials and examples made for INSPIRE: https://datacoveeu.github.io/API4INSPIRE/sensorthingsapi/1_Home.html
GeotechIE proposes to reuse and extend this data model to accommodate the provision of borehole data. See STA Borehole Model