An Introduction to OGC API - Processes¶
Introduction¶
The OGC API — Processes standard supports the wrapping of computational tasks into executable processes that can be offered by a server through a Web API and be invoked by a client application. The standard specifies a processing interface to communicate over a RESTful protocol using JavaScript Object Notation (JSON) encodings. The standard leverages concepts from the OGC Web Processing Service (WPS) 2.0 Interface Standard but does not require implementation of a WPS. The Core part of the standard is called OGC API - Processes - Part 1: Core. The Core part of the standard supports the wrapping of computational tasks into executable processes that can be offered by a server through a Web API and be invoked by a client application either synchronously or asynchronously. Examples of computational processes that can be supported by implementations of this specification include raster algebra, geometry buffering, constructive area geometry, routing, imagery analysis and several others.
Note
This tutorial module is not intended to be a replacement to the actual OGC API - Processes - Part 1: Core standard. The tutorial intentionally focuses on a subset of capabilities in order to get the student started with using the standard. Please refer to the OGC API - Processes - Part 1: Core standard for additional detail.
Background¶
- History
Several of the concepts specified in OGC API - Processes originated in work specifying a RESTful interface for WPS 2.0. From February 2019 onwards, all work relating to a RESTful interface for the WPS 2.0 was changed to focus on OGC API - Processes.
- Versions
OGC API - Processes - Part 1: Core version 1.0.0 is the current latest version
- Test Suite
- Draft Test suites are available for:
- Implementations
Implementations can be found here <https://github.com/opengeospatial/ogcapi-processes/blob/master/implementations.adoc>
Usage¶
OGC API - Processes - Part 1: Core supports the wrapping of computational tasks into executable processes that can be offered by a server through a Web API and be invoked by a client application. Government agencies, private organisations and academic institutes use the OGC API - Processes standard to provide implementations of geospatial algorithms that process data. The benefit of this is that the processing of geospatial data, including data from sensors, can be distributed thereby allowing for more capacity to process larger amounts of data.
Relation to other OGC Standards¶
OGC Web Processing Service Interface Standard (WPS): The WPS Standard provides a standard interface that simplifies the task of making simple or complex computational geospatial processing services accessible via web services. The OGC API — Processes Standard is a newer and more modern way of programming and interacting with resources over the web while allowing better integration into existing software packages. The OGC API — Processes Standard addresses all of the use cases that were addressed by the WPS Standard, while also leveraging the OpenAPI specification and a resource-oriented approach.
Overview of Resources¶
OGC API - Processes - Part 1: Core defines the resources listed in the following table.
Resource |
Path |
Purpose |
|---|---|---|
Landing page |
/ |
This is the top-level resource, which serves as an entry point. |
Conformance declaration |
/conformance |
This resource presents information about the functionality that is implemented by the server. |
API Definition |
/api |
This resource provides metadata about the API itself. Note use of /api on the server is optional and the API definition may be hosted on completely separate server. |
Process list |
/processes |
Process identifiers, links to process descriptions. |
Process description |
/processes/{processID} |
Retrieves a process description. |
Process execution |
/processes/{processID}/execution |
Creates and executes a job. |
Job status info |
/jobs/{jobID} |
Retrieves information about the status of a job. |
Job results |
/jobs/{jobID}/results |
Retrieves the result(s) of a job. |
Job list |
/jobs |
Retrieves the list of jobs. |
Job Deletion |
/jobs/{jobID} |
Cancels and deletes a job. |
Example¶
This ZOO-Project demonstration server from OGC Testbed-17 implements a variety of processing algorithms through an interface that conforms to OGC API - Processes.
The processes offered by the server can be browsed at http://tb17.geolabs.fr:8090/ogc-api/processes.html