# Third-party notices

## geomagnetism 0.2.0

Yohai Compass includes an adapted browser-only subset of `geomagnetism@0.2.0` for WMM2025 magnetic-field calculation.

- Upstream project: `naturalatlas/geomagnetism`
- Upstream version/tag: `v0.2.0`
- Upstream copyright: Copyright © 2015–2024 Natural Atlas, Inc. & Contributors
- License: Apache License 2.0
- License copy: `geomagnetism-0.2.0-LICENSE.txt`
- Modified file: `public/js/vendor/geomagnetism-wmm2025.js`

The adapted file removes CommonJS/module-loading concerns and retains only the WMM2025 calculation path needed by Yohai Compass.

## World Magnetic Model 2025

WMM2025 model values and coefficient information are sourced from NOAA NCEI / British Geological Survey materials.

NOAA NCEI states that the WMM source code is U.S. Government public-domain material. Yohai Compass separately retains the Apache-2.0 license obligations for the adapted `geomagnetism` implementation above.

Official model page:

https://www.ncei.noaa.gov/products/world-magnetic-model