Earthdata Forum

I downloaded some GEDI data to investigate it's canopy height product. For the geolocation of a single measurement, I used the values from lat_lowestmode and lon_lowestmode. However, when I visualized the results on a map in qgis, I saw that the datapoints don't come in a straight line. They wobble, but more importantly, some points are clearly beside the main track, about 240 meters away from it, while the main track has a gap in respective ___location. I added as an attachment an image of what I mean.

The particular gedi product was "GEDI02_A_2019347154443_O05678_03_T01317_02_003_01_V002", BEAM0001. One of the off-track points is eg at lon 34.297345 and lat 1.589293.

Is such behaviour to be expected from gedi data? If so, then why?

Hi @heidot we are taking a look at this and will follow up when we have additional information.

Hello @heidot This could be caused by a cloud (or a cliff with significantly higher elevation than its surroundings). When the laser beam comes in at an angle, its triggered closer to the spacecraft than its neighboring footprint, which when you look at it in lat/lon space makes an apparent shift like that. It this case, using quality_flag will help you eliminate the laser shots with impacted quality. you can use degrade_flag=0 and quality_flag = 1 as a general cleaning approach. Please let us know if you have any additional questions. Thanks -- Danielle