Contributing to the Documentation

Documentation is important and we encourage any improvements that can be made. If you believe the documentation is not clear please contribute a change to improve the documentation for all users.

Any change to the Iris project whether it is a bugfix, new feature or documentation update must use the Development Workflow.


The documentation uses specific packages that need to be present. Please see Installing Iris for instructions.


The build can be run from the documentation directory iris/docs/iris/src.

The build output for the html is found in the _build/html sub directory. When updating the documentation ensure the html build has no errors or warnings otherwise it may fail the automated cirrus-ci build.

Once the build is complete, if it is rerun it will only rebuild the impacted build artefacts so should take less time.

There is also an option to perform a build but skip the Gallery creation completely. This can be achieved via:

make html-noplot

If you wish to run a clean build you can run:

make clean
make html

This is useful for a final test before committing your changes.


In order to preserve a clean build for the html, all warnings have been promoted to be errors to ensure they are addressed. This only applies when make html is run.


There are a ways to test various aspects of the documentation. The make commands shown below can be run in the iris/docs/iris or iris/docs/iris/src directory.

Each Gallery entry has a corresponding test. To run the tests:

make gallerytest

Many documentation pages includes python code itself that can be run to ensure it is still valid or to demonstrate examples. To ensure these tests pass run:

make doctest

See for an example of using the doctest approach.

The hyperlinks in the documentation can be checked automatically. If there is a link that is known to work it can be excluded from the checks by adding it to the linkcheck_ignore array that is defined in the The hyperlink check can be run via:

make linkcheck

If this fails check the output for the text broken and then correct or ignore the url.


In addition to the automated cirrus-ci build of all the documentation build options above, the service is also used. The configuration of this held in a file in the root of the github Iris project named .readthedocs.yml.

Generating API Documentation

In order to auto generate the API documentation based upon the docstrings a custom set of python scripts are used, these are located in the directory iris/docs/iris/src/sphinxext. Once the make html command has been run, the output of these scripts can be found in iris/docs/iris/src/generated/api.

If there is a particularly troublesome module that breaks the make html you can exclude the module from the API documentation. Add the entry to the exclude_modules tuple list in the iris/docs/iris/src/sphinxext/ file.