Contributing to geocat-comp#


Thank you for considering making a contribution to geocat-comp! There are many ways to contribute to this project, including reporting bugs, requesting additional or new functionality, improving our documentation, or contributing your own code and we appreciate all of them.

If you have any questions, please feel free to reach out to us on GitHub Discussions. You can also reach us by email at

Where to start#

Look through our open issues and see if there is anything you would like to take on! We recommend working with core developers to implement new functionality. We can help you get started and make sure your code is consistent with the rest of the project.

Also check out any beginner-friendly issues we have tagged with good first issue.

We do not officially “assign” issues to contributors, but if you are interested in working on an issue, please comment on the issue to let us know you are working on it. This will help us avoid duplicate work.

The code for geocat-comp is hosted on GitHub. If you do not have one, you will need to create a free GitHub account. The GitHub Quickstart Guide is a great place to get started with git and GitHub.

Reporting bugs#

Something not working as expected? We would love to hear about it! Please report any bugs you find by opening an issue on GitHub. See our bug report template to get started.

When reporting a bug, please include as much information as possible. This will help us reproduce the bug and fix it efficiently. For more information on how to write a good bug report, see this stackoverflow post on how to make a good bug report.

Requesting new features#

Have an idea for a new feature? Want to know how to do something in Python that you used to do in NCL? See our feature request template to get started.

You can also use our Feature Request Form to submit a feature request.

Improving Documentation#

We are always looking for ways to improve our documentation. If you find something that is unclear or confusing, please let us know by opening an issue. To contribute to our documentation yourself, see the Documentation section of this guide.

Development workflow overview#

This is a brief overview of the development workflow we use for geocat-comp. A more detailed description of each step is provided in following sections.

Get set up to develop on your local machine

  1. Fork and clone the repository.

  2. Create a development environment.

  3. Create a branch for your changes.

  4. Install pre-commit hooks.

Make your changes

  1. Understanding the codebase.

  2. Write and run tests.

  3. Generate and check the documentation.

Contribute your code

  1. Push your changes to your fork.

  2. Open a pull request.

  3. Address feedback.

  4. Wait for your pull request to be merged.

  5. Delete your branch.

Get set up to develop on your local machine#

Fork and clone the repository#

Get started by forking the NCAR/geocat-comp repository on GitHub. To do this, find the “Fork” button near the top of the page and click it. This will create a copy of the project under your personal github account.

Next, clone your forked copy to your local machine.

git clone

Enter the project folder and set the upstream remote to the NCAR/geocat-comp repository. This will allow you to keep your fork up to date with the main repository.

cd geocat-comp git remote add upstream

For more information, see the GitHub quickstart section on forking a repository.

Create a development environment#

To run and test any changes you make in geocat-comp, you will need to create a development environment. We recommend installing and using conda and/or mamba.

Use the following commands to create a new conda environment to develop geocat-comp in.

# Create a new conda environment
conda create -c conda-forge -n geocat_comp_build python=3.11

# Use the environment file to populate the environment with the required dependencies
conda env update -f build_envs/environment.yml

# Activate your new environment
conda activate geocat_comp_build

# Install your local copy of geocat-comp in interactive mode
pip install -e .

To test your new install, open a python session and try importing geocat.comp. You can also try printing the version number, which should be unique to the latest commit on your fork.

>>> import geocat.comp as gc
>>> gc.__version__

You can follow a similar process to create our documentation environment, gc-docs from the build_envs/docs.yml file.

See the conda documentation for more information.

Create a branch for your changes#

We highly recommend creating a new branch on your fork for each new feature or bug that you work on.

To create and check out a new branch, use the following command:

git checkout -b <branch-name>

Track upstream changes for git pull and git push

git branch --set-upstream-to=origin/<branch-name> <branch-name>

You can see a list of all branches in your local repository by running:

git branch

For more information on branching, check out this learn git branching interactive tool.

Install pre-commit hooks#

geocat-comp uses pre-commit hooks to ensure a standardized base-level code formatting and style.

The pre-commit package is installed by default when using the build_envs/environment.yml file. To set up the pre-commit hooks, run the following command from the root of the repository:

pre-commit install

Now, whenever you commit changes, the pre-commit hooks will run and may make small modifications to your code. If the pre-commit hooks make any changes, you will need to re-add the files and commit them again in order to successfully make the commit.

To manually run the pre-commit hooks, use the following command:

pre-commit run --all-files

If codespell flags on a jargon specific term, you can add the term to the ignore-words-list in`pyproject.toml`. Any words added to the ignore-words-list should be lower-case.

You can skip the pre-commit hooks by adding the --no-verify flag to your commit command like this:

git commit -m "your commit message" --no-verify

For more information on pre-commit hooks, see the pre-commit documentation.

Make your changes#

After you’re all set up to develop geocat-comp, you can start making your changes. This section describes where, how, and what to change to add your contributions to the geocat-comp codebase.

Understanding the codebase#

The geocat-comp top-level directory is organized as follows:

├── build_envs
├── docs
├── geocat
│   └── comp
└── test
  • The build_envs directory contains the environment.yml file used to create your development environment. It also contains additional environment files used for testing and building the documentation.

  • The docs directory contains the sphinx documentation for geocat-comp.

  • The geocat/comp directory, contains the code for the geocat.comp package. This is the place to add new functionality. The geocat.comp code is organized into modules, each of which is contained in its own file. It is recommended that you add new functionality to an existing file, though it may be appropriate to make a new file.

  • The test directory contains the unit tests for geocat-comp. Each module in geocat.comp has a corresponding test module in the test directory.

When adding new functionality, there are multiple auxiliary files that you may need to modify to incorporate your code into the package. These include:

  • geocat/comp/ This file imports all of the functions intended for the public API.

  • docs/internal_api/index.rst and docs/user_api/index.rst: These files are used to generate the API documentation from docstrings.

  • docs/release-notes.rst: This file documents changes to the codebase that we add to in the same PR as the code changes.

  • tests/test_<module>.py: This file contains the unit tests for the module you are adding to. It is highly encouraged to add unit tests for any new functionality you add to geocat-comp.

Write and run tests#

geocat-comp uses pytest for unit tests, so we encourage you to write new tests using pytest as well.

To run the tests locally, use the following command from the root of the repository:


To run a specific test, use the following command:

pytest tests/

These tests will also run automatically when you open a pull request using GitHub Actions and the .github/workflows/ci.yml file.

See the pytest documentation for more information.


geocat-comp uses sphinx and ReadTheDocs to build and host the documentation.


The most common situation in which you will need to add to the documentation is through docstrings.

geocat-comp uses numpydoc style docstrings. See sphinx’s example numpydoc docstring.

To include your docstring documentation in the API reference, you will need to add it to either the docs/internal_api/index.rst or docs/user_api/index.rst file, depending on whether the function is intended for internal or external use.

Editing other documentation files#

We welcome changes and improvements to all parts of our documentation (including this guide)! You can find these files in the docs directory.

These files are mainly written in reStructuredText, but additional file types such as .md and .ipynb are also used.

Important documentation files to know about include:

  • docs/index.rst: This file is the main page of the documentation. Files added to toctree blocks in this file will be included in the documentation as top-level subpages.

  • docs/contrib.rst: This file is the source for this guide!

  • docs/ This file contains the configuration for building the documentation.

  • docs/examples/*.ipynb, docs/examples.rst, and docs/gallery.yml: These files are used to generate the jupyter notebook examples in the documentation. Notebooks in the docs/examples/ directory are added to the documentation by adding them to the toctree in docs/examples.rst and linked to their cover picture by adding them to the docs/gallery.yml file.

See the sphinx documentation for more information about writing sphinx documentation.

Generate the documentation locally#

To generate the documentation locally, follow the steps below.

  1. Create and activate the gc-docs conda environment using the build_envs/docs.yml file.

  2. Enter the docs directory.

  3. Run make html or to build the documentation.

  4. Open docs/_build/html/index.html in your browser to view the documentation.

Check the documentation#

As well as checking local documentation generation, you should also check the preview documentation generated as part of a PR. To do this, scroll down to the “checks” section of the PR and click on the “Details” link next to the “docs/” check. This will take you to the corresponding build on ReadTheDocs, where you can view the documentation built from your PR and see any warnings or errors on your build.

Contribute your code#

Once you have prepared your changes and are ready for them to be reviewed by the GeoCAT team, you can open a pull request. This section describes how to open a pull request and what to expect after you open it.

Push your changes to your fork#

Once you have made your changes locally, you will need to push them to your branch on your fork on GitHub. To do this, use the following command:

git push

From here, you can request that your changes be merged into the main repository in the form of a pull request.

Open a pull request#

GitHub has extensive pull request guides and documentation that we recommend. This section describes the basics for our workflow.

From your branch on your fork, open the “Pull requests” tab and click the “New pull request” button. Make sure the “base repository” is “NCAR/geocat-comp” and the “base” branch is set to “main”, with the “head repository” and “compare” branch set to your fork and prepared branch, respectively.

From this page, you can see a view of the changes you have made in your branch.

We recommend adding a short, descriptive title to your pull request. The body of the pull request should autofill with our pull request template, which has it’s own set of directions. Please fill out the relevant sections of the template, including adding a more detailed description of your changes.

Once you have filled out the template, click the “Create pull request” button. This will open your pull request on the geocat-comp repository.

If you want to open a pull request but are not ready for it to be reviewed, you can open the pull request as a draft. This is also a good way to get feedback on your work that might not be ready to contribute yet.

Address feedback#

After you open your pull request, the GeoCAT team will review it and may provide feedback like asking for changes or suggesting improvements. You can address this feedback by making changes to your branch and pushing them to your fork. The pull request will automatically update with your changes.

The GeoCAT team appreciates your contributions and the interactive process of reviewing pull requests, and will do our best to review your pull request in a timely manner. It is totally normal to have to make several rounds of changes to your pull request before it is ready to be merged, especially if you are new to the project.

Once your pull request is approved by a core maintainer and passes the relevant checks, it will be merged into the main repository!

Delete your branch#

We recommend deleting your branch after your pull request is merged. This will help keep your fork clean and organized, but is not required.