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From "Alan R Williams (JIRA)" <>
Subject [jira] [Commented] (COMDEV-122) Taverna: Open Geospatial Consortium Web Processing Service support
Date Mon, 09 Mar 2015 14:07:38 GMT


Alan R Williams commented on COMDEV-122:

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> Taverna: Open Geospatial Consortium Web Processing Service support
> ------------------------------------------------------------------
>                 Key: COMDEV-122
>                 URL:
>             Project: Community Development
>          Issue Type: Bug
>         Environment: Java, Maven
>            Reporter: Alan R Williams
>              Labels: gsoc, gsoc2015, java, mentor
> Project: Apache Taverna (incubating)
> Mentor: Alan Robert Williams <>
> Apache Taverna,,  “is an open source and domain-independent
Workflow Management System – a suite of tools used to design and execute scientific workflows
and aid in silico experimentation”. The workflows consist of instances of services joined
by connections. There are different types of services, such as making a REST call, running
an R script or requesting information from a user.
> “The Open Geospatial Consortium (OGC) is an international industry consortium of 511
companies, government agencies and universities participating in a consensus process to develop
publicly available interface standards. OGC® Standards support interoperable solutions that
"geo-enable" the Web, wireless and location-based services and mainstream IT. The standards
empower technology developers to make complex spatial information and services accessible
and useful with all kinds of applications.” - 
> “The OGC’s Web Processing Standard Service Interface Standard provides rules for
standardizing how inputs and outputs (requests and responses) for geospatial processing services,
such as polygon overlay. The standard also 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 they
can be available at the server.” - 
> There have been several requests from users, including two in 2015, for Taverna to be
able to include the calling of WPS services within workflows.
> The WPS services can be discovered and invoked by either WSDL operations or REST calls
to the WPS Server. However, the operations of a server do not take account of the processes
that are available on the server. Instead, they allow you to ask what processes are known
to the server, and to execute a process on the server. Exactly the same operations are used
to call different processes. You have to specify the process name as a parameter to the operation.
> These generic operations are not very useful when you want to call specific processes
in a workflow. Instead, you want an operation to call a specific process. So each process
known to the server would have its own operation(s).
> One server-side solution, PyWPS has been developed
. PyWPS makes a WSDL that calls the specific operations. However, this involves making changes
to the WPS server, to which the workflow designer may not have access. It is also only available
for installation on certain types of WPS server.
> Some initial work has been made to create Taverna-side solutions, so that Taverna would
be able to discover the WPS services and to invoke them,
and . Both of these have limitations and have
not been extensively tested. They are similar in their use of the 52°North WPS library
. They also work with Taverna 2.5 rather than the currently being developed Taverna 3.
> This proposed GSOC project is to, in collaboration with dev@taverna and the mentor
> # Improve/complete the existing Taverna 2.5 WPS prototype support
> ## Discovery of WPS services from a user-specified WPS server
> ## Configuration of WPS services
> ## Execution of WPS services
> # Test WPS support using pre-selected WPS servers and services
> # Migrate the WPS support to the Taverna 3 codebase
> # Document the Taverna 3 WPS service support
> There are other related OGC standards such as the Web Map Service (WMS) and Sensor Observation
Service (SOS). The project can be extended to include the discovery and execution of such
> Your WPS service would be added to Apache Taverna, so you would be a part of the Apache
Taverna developer community which will be able
to give feedback, testing and guidance for this GSOC project and beyond.

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