computer science

Web Processing Service

Web Processing 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 Web Processing Service rather than just read about it. In short: The OGC Web Processing Service (WPS) Interface Standard provides rules for standardizing inputs and outputs (requests and responses) for invoking geospatial processing services, such as polygon overlay, as a web service. The WPS standard defines how a client can request the execution of a process, and how the output from the process is handled.

Key takeaways

Web Processing 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 Web Processing Service to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Web Processing Service from memory before moving on to harder problems.

Reference excerpt

The OGC Web Processing Service (WPS) Interface Standard provides rules for standardizing inputs and outputs (requests and responses) for invoking geospatial processing services, such as polygon overlay, as a web service. The WPS standard defines how a client can request the execution of a process, and how the output from the process is handled. It defines an interface that facilitates the publishing of geospatial processes and clients’ discovery of and binding to those processes. The data required by the WPS can be delivered across a network or it can be available at the server. WPS can describe any calculation (i.e. process) including all of its inputs and outputs, and trigger its execution as a web service. WPS supports simultaneous exposure of processes via HTTP GET, HTTP POST, and SOAP, thus allowing the client to choose the most appropriate interface mechanism. The specific processes served up by a WPS implementation are defined by the owner of that implementation. Although WPS was designed to work with spatially referenced data, it can be used with any kind of data. WPS makes it possible to publish, find, and bind to processes in a standardized and thus interoperable fashion. Theoretically, it is transport/platform neutral (like SOAP), but in practice it has only been specified for HTTP.

Operations WPS defines three operations:

GetCapabilities returns service-level metadata DescribeProcess returns a description of a process including its inputs and outputs Execute returns the output(s) of a process WPS operations are invoked by submitting XML or URL-encoded requests to an Online Resource URL. When requesting an Execute operation the HTTP request identifies the inputs, the name of process to be executed, and the form of output to be provided.

Properties WPS has the following properties:

Inputs can be web-accessible URLs or embedded in the request. Outputs can be stored as web-accessible URLs or embedded in the response. For a single output such as a GIF image, WPS can return the output directly, without any XML wrapper. It supports multiple input and output formats. It supports long-running processes. It supports SOAP and WSDL. A WPS is usually not invoked directly. More often, it is invoked by a client application that provides the user with interactive controls. This client application may or may not be web-based. WPS version 2.0 was released in 2015. Previous version 1.0.0 was released to the public in June 2007. Version 0.4.0 was released as an OGC Request for Public Comment in 2005 and implemented by several early adopters.

See also WPS Simple Web Feature Service Web Map Service

External links OpenGIS Web Processing Service (WPS) Standard, Version 1.0.0 WPS resources at geoprocessing.info OSGeo Evaluation of WPS 0.4.0 OGC WPS Interoperability Experiment press release OGC WPS Request for Public Comments deegree Open source Java implementation (WPS 0.4.0 & WPS 1.0.0) with example processes WPSint Open source Java implementation of WPS 0.4.0 (includes a generic client) PyWPS Open source Python implementation of WPS 1.0.0 ZOO Project WPS implementation of WPS 1.0.0 and 2.0.0 WPS.NET Open source .NET implementation of WPS 1.0.0 QGIS WPS client OGC-Services.NET - Free List of OGC Services (New Services can be added manually) OpenLayers Contains WPS Parser

Worked examples

Example 1 — a first encounter with Web Processing Service

Start with the simplest possible case. Write down what Web Processing 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 Web Processing 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 Web Processing 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 Web Processing Service

In research: Web Processing 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 Web Processing 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: Web Processing Service is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cartography, GIS software, Open Geospatial Consortium, so understanding it makes those chapters shorter.
In everyday life: Look for Web Processing 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.

Affiliate

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

How to study Web Processing Service in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Web Processing 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 Web Processing Service out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Web Processing Service in simple terms?

Why does Web Processing 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 Web Processing 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 Web Processing Service.