GEDI provides billions of geodetic class laser altimetry observations of the Earth's topography, even below dense canopies.
Precisely geolocated surface returns from spaceborne laser altimetry provide valuable observations of the Earth’s topography to improve Digital Elevation Models (DEMs) and as a reference for measuring surface elevation change. These laser altimeter data are geolocated within a precise and well defined terrestrial reference frame, and, as such, form a data set by which other surface elevation data can be calibrated. ICESat laser altimeter surface elevation observations have been used extensively to validate and quantify the errors in regional and global DEMs constructed from stereo photogrammetry and radar data. ICESat laser altimeter surface elevation observations have also been used as ground control observations to significantly improve InSAR-derived DEMs for both baseline refinements and for controlling mosaicking of multiple DEMs. Spaceborne laser altimeter observations have been used to remove large-scale systematic biases as well as radar system induced errors, including impacts from vegetation cover. The precisely geolocated surface elevation observations obtained by GEDI represent a significant improvement in spatial sampling at the footprint level over ICESat, and represent a significant improvement in spatial track sampling over ICESat and ICESat-2 between ± 51.6° latitude. GEDI’s dense track sampling and precise geolocation form the basis of an important data set of ground control points to validate and calibrate global and regional DEMs and as a reference for surface elevation change.
