Contributing Guidelines

We welcome contributions to EarthPy. When contributing, please follow the guidelines below and adhere to the EarthPy Code of Conduct.

At this stage of development, we are developing a set of usable wrapper functions that help make working with earth systems data easier. We are open to new functionality but are currently trying to ensure our package is stable, operational and well documented.

When submitting a change to the repository, please first create an issue that covers the item that you’d like to change, update or enhance. Once a discussion has yielded a vote of support for that addition to the package, you are ready to submit a pull request.

If you are proposing a feature:

  • Explain in detail how it would work.

  • Keep the scope as narrow as possible, to make it easier to implement.

Get Started!

Ready to contribute? Here’s how to set up EarthPy for local development.

1. Fork the repository on GitHub

To create your own copy of the repository on GitHub, navigate to the earthlab/earthpy repository and click the Fork button in the top-right corner of the page.

2. Clone your fork locally

Use git clone to get a local copy of your EarthPy repository on your local filesystem:

$ git clone
$ cd earthpy/

3. Set up your fork for local development

Create an environment

Using conda, there are two options.

1. The easiest option is to create an environment from the environment.yml file. Note that this will only allow you to test against one version of python locally, but this is the recommended option on Windows and MacOS:

$ conda env create -f environment.yml
$ conda activate earthpy-dev

2. If you are comfortable debugging local system library installations, and want to be able to test against multiple versions of python locally, you can create an empty conda environment:

$ conda create -n earthpy-dev python=3.7
$ conda activate earthpy-dev

Or, if you prefer to use virtualenv rather than conda:

$ virtualenv earthpy-dev
$ source earthpy-dev/bin/activate

Install the package

Once your earthpy-dev environment is activated, install EarthPy in editable mode, along with the development requirements and pre-commit hooks:

$ pip install -e .
$ pip install -r dev-requirements.txt
$ pre-commit install

4. Create a branch for local development

Use the git checkout command to create your own branch, and pick a name that describes the changes that you are making:

$ git checkout -b name-of-your-bugfix-or-feature

Now you can make your changes locally.

5. Test the package

Ensure that the tests pass, and the documentation builds successfully:

$ pytest
$ make docs

Note to Windows users

To use make you will need to install and configure GNU Make for Windows, e.g., using chocolatey:

Optional: testing multiple python versions locally

To test against multiple versions of python, you can use tox. This step is optional, as tox will test against multiple versions as part of EarthPy’s continuous integration pipeline. To use tox, you must be able to install EarthPy’s dependencies without using the environment.yml file, i.e., you must be able to install EarthPy and its dependencies with pip.

Running tox is as simple as:

$ tox

If you are using conda and you get get InterpreterNotFound errors when running tox, you may need to pip install tox-conda.

6. Commit and push your changes

Once you are sure that all tests are passing, you can commit your changes and push to GitHub:

$ git add .
$ git commit -m "Your detailed description of your changes."
$ git push origin name-of-your-bugfix-or-feature

7. Submit a pull request on GitHub

When submitting a pull request:

  • All existing tests should pass. Please make sure that the test suite passes, both locally and on Travis CI Status on Travis will be visible on a pull request. If you want to enable Travis CI on your own fork, please read the getting started docs.

  • New functionality should include tests. Please write reasonable tests for your code and make sure that they pass on your pull request.

  • Classes, methods, functions, etc. should have docstrings. The first line of a docstring should be a standalone summary. Parameters and return values should be documented explicitly.

  • The API documentation is automatically generated from docstrings, which should conform to NumpPy styling. For examples, see the Napoleon docs.

  • Please note that tests are also run via Travis-CI on our documentation. So be sure that any .rst file submissions are properly formatted and tests are passing.

Documentation Updates

Improving the documentation and testing for code already in EarthPy is a great way to get started if you’d like to make a contribution. Please note that our documentation files are in ReStructuredText (.rst) format and format your pull request accordingly.

To build the documentation, use the command:

$ make docs

By default make docs will only rebuild the documentation if source files (e.g., .py or .rst files) have changed. To force a rebuild, use make -B docs. You can preview the generated documentation by opening docs/_build/html/index.html in a web browser.

Earthpy uses doctest to test code in the documentation, which includes docstrings in EarthPy’s modules, and code chunks in the reStructuredText source files. This enables the actual output of code examples to be checked against expected output. When the output of an example is not always identical (e.g., the memory address of an object), use an ellipsis (...) to match any substring of the actual output, e.g.:

>>> print(list(range(20)))
[0, 1, ..., 18, 19]

Earthpy also uses the Matplotlib plot directive in the documentation to generate figures. To include a figure in an example, prefix the example with .. plot::, e.g.,:

.. plot::

   >>> import matplotlib.pyplot as plt
   >>> plt.plot([1, 2, 3], [4, 5, 6])

Code Style

  • EarthPy currently only supports Python 3 (3.5+). Please test code locally in Python 3 when possible (all supported versions will be automatically tested on Travis CI).

  • EarthPy uses a pre-commit hook that runs the black code autoformatter. Be sure to execute pre-commit install as described above, which will cause black to autoformat code prior to commits. If this step is skipped, black may cause build failures on Travis CI due to formatting issues.

  • Follow PEP 8 when possible. Some standards that we follow include:

    • The first word of a comment should be capitalized with a space following the # sign like this: # This is a comment here

    • Variable and function names should be all lowercase with words separated by _.

    • Class definitions should use camel case - example: ClassNameHere .

  • Imports should be grouped with standard library imports first, 3rd-party libraries next, and EarthPy imports third following PEP 8 standards. Within each grouping, imports should be alphabetized. Always use absolute imports when possible, and explicit relative imports for local imports when necessary in tests.


A reminder for the maintainers on how to deploy. Make sure all your changes are committed, then run:

$ bumpversion patch # possible: major / minor / patch

This will increment the version according to a major release (e.g., 0.1.0 to 1.0.0), a minor release (e.g., 0.1.0 to 0.2.0), or a patch (e.g., 0.1.0 to 0.1.1), following the guidelines for semantic versioning:

Bumpversion updates the version number throughout the package, and generates a git commit along with an associated git tag for the new version. For more on bumpversion, see:

To deploy EarthPy, push the commit and the version tags:

$ git push
$ git push --tags

Travis will then deploy to PyPI if the build succeeds. Travis will only deploy to PyPI on tagged commits, so remember to push the tags. Once that is done, create a release on GitHub for the new version.

Data Generated for Testing

If a test requires a data object such as a GeoDataFrame or numpy array, and copies of that data object are required by multiple tests, we can use [pytest fixtures]( to cleanly create and tear down those objects independently for each test. See [earthpy/tests/](earthpy/tests/ for fixture definitions, and [earthpy/tests/](earthpy/tests/ for example usage of fixtures in tests.