Datum Conversion for SWOT Data

Community Tutorials

Use the Handbook

Please first see the SWOT Data User Handbook sections 3.3.2 for the ITRF, 3.3.3 on the reference ellipsoid and 11.3.1 on the geoid. In addition, section 3.1.23 gives detailed information about Height with section 3.1.24 elaborating on Sea Surface Height Anomalies and 3.1.25 elaborating on Water Surface Elevation over inland waters.

Community Tutorials

As a summary, SWOT data is referenced to the WGS84 reference ellipsoid as a first step, and in a second step referenced to the EGM2008 geoid that references WGS84 for the vertical datum. To get a direct conversion with another dataset, it is easiest to transform all local data to the EGM2008 geoid. For the horizontal datum, SWOT uses ITRF 2014 in reference to the WGS84 reference ellipsoid. We recognize these conversions are different globally and depending on the data being used to compare, but we have collected a few community examples of direct comparisons to share below:

1. Comparing USGS gage data and SWOT data in the United States - Python Notebook

2. Converting the SWOT Frame and Geoid in Canada - Google Colab Section from Canadian Colleagues

For More Help

If you have any questions for your specific region, please ask in the Earthdata Forum and experts should be able to help.