May 20, 2020

NASA's space-borne LiDAR, The Global Ecosystem Dynamics Investigation (GEDI) was launched to the International Space Station on December 5th, 2018. Its purpose is to map global ecosystem structure, including forest health and productivity. From GEDI waveforms, four types of structural information can be extracted: surface topography, canopy height metrics, canopy cover metrics, and vertical structure metrics. The GEDI instrument produces eight tracks, with 600 m cross and 60 m along-track return separation. Each return has a footprint of 25 m with a horizontal accuracy of +/- 9m. Over time data gaps will be infilled, resulting in full global coverage.

An initial look at GEDI data extracted over plantations in Uruguay shows that the relative height metrics align well with plantation height measurements. These results are promising and further support the development of plantation monitoring approaches that integrate satellite observations, time-series analysis, and LiDAR data.

The area shown to the right is situated in northern Uruguay. The map shows a Sentinel-2 image captured in late April 2019 overlain with canopy height metrics extracted from the GEDI_02B product (GEDI Canopy Cover and Vertical Profile Metrics) for the same period. The map inset shows the full extent of the dataset, with all eight tracks visible. While the spatial coverage of the GEDI dataset is currently limited, it will, however, increase as more data is captured. Each laser return provides a measurement of canopy height.

To support the map, a 3D representation of the GEDI data below visualises the variation in canopy height across the sample area.