License
=======

pyhnhtools License
------------------

This project is licensed under the **GNU General Public License v3.0 or later (GPL-3.0-or-later)**.

See the LICENSE file in the repository for the full text.

For more information, visit: https://www.gnu.org/licenses/gpl-3.0.en.html

Why GPL-3.0?
^^^^^^^^^^^^

This project uses GPL-3.0 because:

1. **PyQt5 Dependency**: The GUI framework PyQt5 is GPL-3.0 licensed
2. **Code Compatibility**: Ensures all code in the project follows the same license
3. **Open Source**: GPL-3.0 is one of the most popular open-source licenses
4. **Protection**: Derivative works must also be GPL-3.0, protecting the codebase

Attribution
-----------

This project includes code derived from:

**Stormwater Management Model (SWMM)**
    - Copyright (c) 2005-2024, United States Environmental Protection Agency
    - Released to the Public Domain
    - Source: https://github.com/USEPA/Stormwater-Management-Model
    - Portions of culvert analysis functionality are translated from the SWMM C source code to Python

Third-Party Licenses
--------------------

This project includes or uses code from:

- **PyQt5**: GPL v3.0 / Commercial License
- **NumPy**: BSD License
- **SciPy**: BSD License
- **Shapely**: BSD License
- **Plotly**: MIT License
- **Dash**: MIT License
- **GeoPandas**: BSD License
- **Sphinx**: BSD License

Contributing
------------

By contributing to this project, you agree that your contributions will be licensed under its GPL-3.0-or-later license.