CEDA Archive Web Download Service

This service allows you to access the data held in the CEDA Archive:

• Browse the archive directory structure
• Log into CEDA for access to restricted datasets
• Download single and multiple files
• View and subset NetCDF file contents
• See in-browser plotting of NASA-Ames files

Additionally, the  OPeNDAP technology underpinning this service allows additional functionality such as accessing file contents directly via the internet from within data processing scripts written within Python, Matlab IDL and other scripting languages. 

Viewing and downloading individual files

• Text files - You may find that some text based files will automatically open in your web browser when selected. You can then download these files by using the Save as... facility on your browser (usually found under the File drop-down menu). Others will start to download directly.
• Binary and Compressed files - these should automatically start to download to your computer. WinZip on Windows or gzip and tar utilities on Linux machine may be needed to unpack the contents.

Download multiple files

When browsing the archive using https://data.ceda.ac.uk, click on the Bulk download button to see the options for bulk download:

The wget tool provides a convenient way for bulk downloading data. However, for data that either has restricted access, or requires you to have a CEDA account for access, you will need to obtain an Archive access token. You can use this token to authenticate yourself when using a wget command to download data. See Using Archive Access Tokens for Scripted Interactions for details of how to obtain and use a token. Note that you will need a CEDA account in order to create a token and, if the data you wish to download has restricted access, you must have applied for and been granted access to the data from your CEDA account.

Plotting NASA-Ames files

NASA-Ames format files with File Format Index (FFI) 1001 can be plotted from the data browser. Any files which are plottable will have a 'plot' link next to them. Following this link will open a new window showing a plot of the first dependent variable against the independent variable (which in most cases should be time). Below the plot is a form which allows you to select another dependent variable to plot. You can also change the scales of the plot and change the plot symbol. The box labelled  Omit points with value allows you to exclude any points from the plot which have a specified value. This can be used to remove any points which are marked with a special value. (Note that the NASA-Ames format itself requires that a 'fill' value is specified for each variable. These values are automatically excluded from the plot).

Once you have made your selection, press the 'Plot' button on the bottom right hand side of the form to generate the plot.

Scripted Interaction with archive via OPeNDAP

OPeNDAP stands for "Open-source Project for a Network Data Access Protocol", and is a data transport architecture and protocol widely used by earth scientists. There are a variety of libraries available to interact with OPeNDAP services. The following are a few example sites detailing libraries for common languages used within the CEDA data community.

Our OpenDAP interface is located here:  http://dap.ceda.ac.uk/thredds/fileServer/

Whist some of these tools may work for public datasets held in the CEDA Archives, users wishing to use data available to registered CEDA users will need to follow additional steps to use security certificates as detailed on the CEDA OPeNDAP:  Scripted interactions help page.