computer science

Sensor Observation Service

Sensor Observation Service is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Sensor Observation Service rather than just read about it. In short: The Sensor Observation Service (SOS) is a web service to query real-time sensor data and sensor data time series and is part of the Sensor Web. The offered sensor data consists of data directly from the sensors, which are encoded in the Sensor Model Language (SensorML), and the measured values in the Observations and Measurements (O & M) encoding format.

Key takeaways

Sensor Observation Service belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Sensor Observation Service to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Sensor Observation Service from memory before moving on to harder problems.

Reference excerpt

The Sensor Observation Service (SOS) is a web service to query real-time sensor data and sensor data time series and is part of the Sensor Web. The offered sensor data consists of data directly from the sensors, which are encoded in the Sensor Model Language (SensorML), and the measured values in the Observations and Measurements (O & M) encoding format. The web service as well as both file formats are open standards and specifications of the same name defined by the Open Geospatial Consortium (OGC). If the SOS supports the transactional profile (SOS-T), new sensors can be registered on the service interface and measuring values be inserted. A SOS implementation can be used both for data from in-situ as well as remote sensing sensors. Furthermore, the sensors can be either mobile or stationary. Since 2007, the SOS is an official OGC standard. The advantage of the SOS is that sensor data - of any kind - is available in a standardized format using standardized operations. Thus the web-based access to sensor data is simplified. It also allows easy integration into existing Spatial Data Infrastructures or Geographic Information Systems. In 2016 OGC approved the SensorThings API standard specification, a new RESTful and JSON-based standard provide functions similar to SOS. As both SensorThings API and SOS are based on the OGC/ISO 19156:2011, the two specifications have been demonstrated in an OGC IoT pilot that they can interoperate with each other.

Operations The SOS has three so-called core operations that must be provided by each implementation. The GetCapabilities operation allows you to query a service for a description of the service interface and the available sensor data. For using the SOS, the GetObservation function is probably the most important. It can be utilized to retrieve data for specific sensors. The DescribeSensor function returns detailed information about a sensor or a sensor system and the producing processes.

Core operations (core profile) GetCapabilities returns an XML service description with information about the interface (offered operations and endpoints) as well as the available sensor data, such as the period for which sensor data is available, sensors that produce the measured values, or phenomena that are observed (for example air temperature). GetObservation allows pull-based querying of observed values, including their metadata. The measured values and their metadata is returned in the Observations and Measurements format (O & M). DescribeSensor - provides sensor metadata in SensorML. The sensor description can contain information about the sensor in general, the identifier and classification, position and observed phenomena, but also details such as calibration data.

Transactional operations (transactional profile) RegisterSensor allows to register a new sensor in a deployed SOS. InsertObservation can be used to insert data for already registered sensors in the SOS.

Extended operations (enhanced profile) GetResult provides the ability to query for sensor readings without the metadata given consistent metadata (e.g. sensor, observed object). GetFeatureOfInterest returns the geoobject whose properties are monitored by sensors in Geography Markup Language encoding. GetFeatureOfInterestTime provides time periods in which measurements of an observed object in the SOS are available. DescribeFeatureType returns the type of the observed geoobjects (XML Schema) DescribeObservationType returns the type of observation (XML Schema), such as om: Measurement). GetObservationById allows to query a specific observation using an identifier returned by the service as response to an InsertObservation operation. DescribeResultModel provides the XML Schema of the measured value, which is particularly important for complex measurements, such as multi-spectral data.

Terminology The OGC has - not only for the SOS - its own well-defined terminology. For better understanding, here are some important terms:

Software The SOS is a standard of the OGC and ultimately only defines a service interface, but not an implementation. There are currently several open-source implementations of the service:

Java SOS implementation by 52°North Java SOS implementation within the deegree framework by the company lat/lon A C implementation of SOS in MapServer Java, Perl and Python implementations by the project OOSTethys A Python implementation as istSOS Also, proprietary implementations exist.

References

External links OpenGIS Sensor Observation Service on the OGC website

Worked examples

Example 1 — a first encounter with Sensor Observation Service

Start with the simplest possible case. Write down what Sensor Observation Service claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Sensor Observation Service before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Sensor Observation Service ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Sensor Observation Service

In research: Sensor Observation Service appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Sensor Observation Service in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Sensor Observation Service is common in secondary-school and first-year university syllabi. It links to neighbouring topics Geographic information systems, Open Geospatial Consortium, Open standards, so understanding it makes those chapters shorter.
In everyday life: Look for Sensor Observation Service outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Sensor Observation Service” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Sensor Observation Service in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sensor Observation Service means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Sensor Observation Service out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sensor Observation Service in simple terms?

Why does Sensor Observation Service matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Sensor Observation Service?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Sensor Observation Service.