These text protos contain composite JPEG/PNG images representing the EGM2008 Earth Gravitational
Model[^1] published by the National Geospatial-Intelligence Agency.[^2]

[^1]: Pavlis, Nikolaos K., et al. "The development and evaluation of the Earth Gravitational Model
2008 (EGM2008)." Journal of geophysical research: solid earth 117.B4 (2012).

[^2]: National Geospatial-Intelligence Agency. “Office of Geomatics.” 2022.
URL: https://earth-info.nga.mil.