CEDA Web Processing Service (WPS)

The  CEDA Web Processing Service, or CEDA WPS, hosts a range of tools written by CEDA staff or imported external tools to help undertake various data preparation tasks. 

What is the WPS Service and what can you do with it?

The CEDA WPS provides a range of online tools to aid using data in the CEDA Archive. These include the ability to subset datasets by time, location and even parameters, such as the MIDAS surface meteorological dataset or model data from ECMWF. For more details of what other capabilities the WPS tools offer please refer to their associated details.

In the following guide you'll see the terms Process and Tools. Here, a Process is a collection of Tools provided together for a common purpose- for example, all those related to working with the data in the MIDAS Dataset Collection are provided under the 'MIDAS Extract' process (e.g. finding relevant stations and extracting sub-sets of data based on some selection criteria).

User Guide

This general user guide to the CEDA WPS outlines basic information about the user interface with a brief summary of each Process (i.e. collection of tools) and links to specific documentation page. Note, although Processes and Tools may be listed in the WPS pages, access to using the tools may depend on which datasets you have access to in the CEDA Archive. Where required, such access can be applied for via the relevant page in the CEDA Data Catalogue service. Please see the individual process and tool documentation for further details.

Getting Started: Sign In

In order to make use of the CEDA Web Processing Service, and so we can provide support if needed, you will first need to login with your CEDA Archive user account. If you don't yet have such an account these are free and easy to set up. See our User Registration and Account Administration help page for guidance on how to do this.

To login go to the CEDA Web Processing Service at: https://ceda-wps-ui.ceda.ac.uk/ and press the  Sign in button in the upper right corner. This will take you to a page presenting you with the option to sign in with your CEDA User Account:

Note: the first time you do this you may be asked to authorise the CEDA-WPS-UI application to access your account details:

Click Authorise

Once signed in your view will change slightly to look like this at the top - note, your username will be displayed:

Service Load Overview: The Dashboard View

The dashboard (accessed by clicking on the dial icon top right) shows some statistics about present and past jobs and users, useful to get an idea of the overall usage and in particular the present load on the service: larger loads may result in longer job run times.

The Dashboard view looks like this:

The Overview gives you an indication of the present load on the CEDA WPS service as a whole - with the number of signed in users, number of jobs available and the number of Web Processing Services (i.e. collections of tools to use) presently available through the service.

The Jobs page gives numbers of jobs presently running, those which have succeeded and the number that have failed.

The People page provides the number of users logged in now, the day so far and for the past week. 

Using the service: The Processes page

The  Processes tab gives a list of available processes (i.e. collections of tools around a common purpose - e.g. a dataset) within the CEDA WPS service. A padlock symbol next to the service name indicates that making use of tools within that service will require your CEDA user account to have additional access to restricted dataset(s).

The Processes page looks like this:

Choosing one of the WPS processes will get a list of available Tools within that Process. In the user interface, each Process has a short description at the top and lists of available tools, each with its own description and the version of the tool presently available. In the example below there are two tools available in the MIDAS Extract process.

To use one of the tools simply click on its title. This will take you to a web form where you can input your selections to use the tool. At the bottom of the form, there will be a  Submit button. Clicking this will submit your process to a processing queue. When the process is submitted you can see your job's progress in using the Monitor section of the WPS service. 

Note: you can also label your jobs on submission which can help later when listing them under the Monitor tool.

Monitor

In  Monitor all your running or finished jobs are listed. The list shows the status and progress of your jobs.

When a job has finished with success you can see the results by clicking the  Details button.

If the result has an output file (XML, text, NetCDF, …) you can view or download this output file by using the Download button under the Outputs tab. The Inputs tab details the form selections made, whilst the Job Log tab shows the log for the process as it ran, which may be helpful if there is an issue. Details can also be viewed in XML if desired.

Suggest/Request/Write a tool

The CEDA WPS is a service that has been designed to scale with both usage, and with available tools. If you would like to see a specific tool in the CEDA WPS, please feel free to suggest this to us or ask about how you can write a Python tool to be included.

Further Reading about the CEDA WPS

The present CEDA WPS is based on the Birdhouse WPS developed by DKRZ and utilises 'Pyramid Phoenix', a web application built with the Python web framework Pyramid. For more information about the WPS and the underlying technology, including how to install it on other systems, see https://pyramid-phoenix.readthedocs.io/en/latest/index.html

Browser compatibility

The CEDA WPS has been tested with the following browsers:

• Firefox 3+
• Chrome v 86 +
• Internet Explorer 8

If you test the CEDA WPS in other browsers and it works, please let CEDA Support know and we will add that to the above list.