Description
The Global Ecosystem Dynamics Investigation (GEDI) mission aims to characterize ecosystem structure and dynamics to enable radically improved quantification and understanding of the Earth’s carbon cycle and biodiversity. The GEDI instrument produces high resolution laser ranging observations of the 3-dimensional structure of the Earth. GEDI is attached to the International Space Station (ISS) and collects data globally between 51.6° N and 51.6° S latitudes at the highest resolution and densest sampling of any light detection and ranging (lidar) instrument in orbit to date. Each GEDI Version 2 granule encompasses one-fourth of an ISS orbit and includes georeferenced metadata to allow for spatial querying and subsetting.
The GEDI instrument was removed from the ISS and placed into storage on March 17, 2023. No data were acquired during the hibernation period from March 17, 2023, to April 24, 2024. GEDI has since been reinstalled on the ISS and resumed operations as of April 26, 2024.
The purpose of the GEDI Level 2A Geolocated Elevation and Height Metrics product (GEDI02_A) is to provide waveform interpretation and extracted products from each GEDI01_B received waveform, including ground elevation, canopy top height, and relative height (RH) metrics. The methodology for generating the GEDI02_A product datasets is adapted from the Land, Vegetation, and Ice Sensor (LVIS) algorithm. The GEDI02_A product is provided in HDF5 format and has a spatial resolution (average footprint) of 25 meters.
The GEDI02_A data product contains 156 layers for each of the eight beams, including ground elevation, canopy top height, relative return energy metrics (e.g., canopy vertical structure), and many other interpreted products from the return waveforms. Additional information for the layers can be found in the GEDI Level 2A Dictionary.
Known Issues
- Data acquisition gaps: GEDI data acquisitions were suspended on December 19, 2019 (2019 Day 353) and resumed on January 8, 2020 (2020 Day 8).
- Incorrect Reference Ground Track (RGT) number in the filename for select GEDI files: GEDI Science Data Products for six orbits on August 7, 2020, and November 12, 2021, had the incorrect RGT number in the filename. There is no impact to the science data, but users should reference this document for the correct RGT numbers.
- Known Issues: Section 8 of the User Guide provides additional information on known issues.
Improvements/Changes from Previous Versions
- Metadata has been updated to include spatial coordinates.
- Granule size has been reduced from one full ISS orbit (~5.83 GB) to four segments per orbit (~1.48 GB).
- Filename has been updated to include segment number and version number.
- Improved geolocation for an orbital segment.
- Added elevation from the SRTM digital elevation model for comparison.
- Modified the method to predict an optimum algorithm setting group per laser shot.
- Added additional land cover datasets related to phenology, urban infrastructure, and water persistence.
- Added selected_mode_flag dataset to root beam group using selected algorithm.
- Removed shots when the laser is not firing.
- Modified file name to include segment number and dataset version.
Version Description
Product Summary
Citation
Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.
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File Naming Convention
The file name begins with the Product Short Name (GEDI02_A), followed by the Julian Date and Time of Acquisition designated as YYYYDDDHHMMSS (2024333190440), the Orbit Number starting with the letter O (O33777), the Sub-Orbit Granule Number (03), Track Number (T03689), the Positioning and Pointing Determination System type where 00 is predict, 01 rapid, 02 and higher is final (02), the Product Generation Executables Version (004), the Granule Production Version (02), the Version Number (V002), and the Data Format (h5).
Documents
USER'S GUIDE
ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD)
GENERAL DOCUMENTATION
Dataset Resources
Publications Citing This Dataset
Variables
Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.
The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.
| Name Sort descending | Description | Units | Data Type | Fill Value | Valid Range | Scale Factor |
|---|---|---|---|---|---|---|
| /BEAM0000/ancillary/l2a_alg_count | Number of L2A algorithm runs present in file | N/A | uint8 | N/A | N/A to 10 | N/A |
| /BEAM0000/beam | Beam identifier | N/A | uint16 | N/A | N/A to 12 | N/A |
| /BEAM0000/channel | Channel identifier | N/A | uint8 | N/A | N/A to 6 | N/A |
| /BEAM0000/degrade_flag | Non-zero values indicate the shot occured during a degraded period. A non-zero tens digit indicates degraded attitude, a non-zero ones digit indicates a degraded trajectory. 3X=ADF CHU solution unavailable (ST-2); 4X=Platform attitude; 5X=Poor solution (filter covariance large); 6X=Data outage (platform attitude gap also); 7X=ST 1+2 unavailable (similar boresight FOV); 8X=ST 1+2+3 unavailable; 9X=ST 1+2+3 and ISS unavailable; X1=Maneuver; X2=GPS data gap; X3=ST blinding; X4=Other; X5=GPS receiver clock drift; X6=X5+X1; X7=X5+X2; X8=X5+X3; X9=X5+X4. | N/A | uint8 | N/A | N/A to 99 | N/A |
| /BEAM0000/delta_time | Transmit time of the shot, measured in seconds from the master_time_epoch. By adding the offset contained within /BEAMXXXX/ancillary/master_time_epoch to delta_time, the time in GPS seconds relative to the GPS epoch can be computed. Equivalent to /BEAMXXXX/master_int+/BEAMXXXX/master_frac. | seconds since 2018-01-01 | float64 | N/A | N/A | N/A |
| /BEAM0000/digital_elevation_model | TanDEM-X elevation at GEDI footprint location | m | float32 | N/A | N/A | N/A |
| /BEAM0000/digital_elevation_model_srtm | SRTM elevation at GEDI footprint location | m | float32 | N/A | N/A | N/A |
| /BEAM0000/elevation_bias_flag | Elevations potentially affected by 4bin (~60cm) ranging error | N/A | uint8 | N/A | N/A to 1 | N/A |
| /BEAM0000/elevation_bin0_error | Error in elevation of bin 0 | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/elev_highestreturn | elevation of highest detected return relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/elev_lowestmode | elevation of center of lowest mode relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/energy_total | Integrated counts in the return waveform relative to the mean noise level | counts | float32 | N/A | N/A to 5000000 | N/A |
| /BEAM0000/geolocation/elevation_1gfit | Elevation corresponding to the center of a single gaussian fit to the waveform, relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elevs_allmodes_a1 | Elevations of all modes detected using algorithm N, relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elevs_allmodes_a2 | Elevations of all modes detected using algorithm N, relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elevs_allmodes_a3 | Elevations of all modes detected using algorithm N, relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elevs_allmodes_a4 | Elevations of all modes detected using algorithm N, relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elevs_allmodes_a5 | Elevations of all modes detected using algorithm N, relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elevs_allmodes_a6 | Elevations of all modes detected using algorithm N, relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_highestreturn_a1 | Elevation of the highest return detected using algorithm N, relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_highestreturn_a2 | Elevation of the highest return detected using algorithm N, relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_highestreturn_a3 | Elevation of the highest return detected using algorithm N, relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_highestreturn_a4 | Elevation of the highest return detected using algorithm N, relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_highestreturn_a5 | Elevation of the highest return detected using algorithm N, relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_highestreturn_a6 | Elevation of the highest return detected using algorithm N, relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_lowestmode_a1 | Elevation of the center of the lowest mode detected using algorithm N,relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_lowestmode_a2 | Elevation of the center of the lowest mode detected using algorithm N,relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_lowestmode_a3 | Elevation of the center of the lowest mode detected using algorithm N,relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_lowestmode_a4 | Elevation of the center of the lowest mode detected using algorithm N,relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_lowestmode_a5 | Elevation of the center of the lowest mode detected using algorithm N,relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_lowestmode_a6 | Elevation of the center of the lowest mode detected using algorithm N,relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_lowestreturn_a1 | Elevation of lowest return detected using algorithm N,relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_lowestreturn_a2 | Elevation of lowest return detected using algorithm N,relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_lowestreturn_a3 | Elevation of lowest return detected using algorithm N,relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_lowestreturn_a4 | Elevation of lowest return detected using algorithm N,relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_lowestreturn_a5 | Elevation of lowest return detected using algorithm N,relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/elev_lowestreturn_a6 | Elevation of lowest return detected using algorithm N,relative to reference ellipsoid | m | float32 | N/A | N/A to 25000 | N/A |
| /BEAM0000/geolocation/energy_lowestmode_a1 | Energy of lowest mode, detected using algorithm N, in the waveform above the mean noise level | counts | float32 | N/A | N/A to 5000000 | N/A |
| /BEAM0000/geolocation/energy_lowestmode_a2 | Energy of lowest mode, detected using algorithm N, in the waveform above the mean noise level | counts | float32 | N/A | N/A to 5000000 | N/A |
| /BEAM0000/geolocation/energy_lowestmode_a3 | Energy of lowest mode, detected using algorithm N, in the waveform above the mean noise level | counts | float32 | N/A | N/A to 5000000 | N/A |
| /BEAM0000/geolocation/energy_lowestmode_a4 | Energy of lowest mode, detected using algorithm N, in the waveform above the mean noise level | counts | float32 | N/A | N/A to 5000000 | N/A |
| /BEAM0000/geolocation/energy_lowestmode_a5 | Energy of lowest mode, detected using algorithm N, in the waveform above the mean noise level | counts | float32 | N/A | N/A to 5000000 | N/A |
| /BEAM0000/geolocation/energy_lowestmode_a6 | Energy of lowest mode, detected using algorithm N, in the waveform above the mean noise level | counts | float32 | N/A | N/A to 5000000 | N/A |
| /BEAM0000/geolocation/latitude_1gfit | Latitude corresponding to the center of a single gaussian fit to the waveform | degrees | float64 | N/A | N/A to 55 | N/A |
| /BEAM0000/geolocation/lats_allmodes_a1 | Latitudes of all modes detected using algorithm N | degrees | float64 | N/A | N/A to 55 | N/A |
| /BEAM0000/geolocation/lats_allmodes_a2 | Latitudes of all modes detected using algorithm N | degrees | float64 | N/A | N/A to 55 | N/A |
| /BEAM0000/geolocation/lats_allmodes_a3 | Latitudes of all modes detected using algorithm N | degrees | float64 | N/A | N/A to 55 | N/A |
| /BEAM0000/geolocation/lats_allmodes_a4 | Latitudes of all modes detected using algorithm N | degrees | float64 | N/A | N/A to 55 | N/A |
| /BEAM0000/geolocation/lats_allmodes_a5 | Latitudes of all modes detected using algorithm N | degrees | float64 | N/A | N/A to 55 | N/A |
| /BEAM0000/geolocation/lats_allmodes_a6 | Latitudes of all modes detected using algorithm N | degrees | float64 | N/A | N/A to 55 | N/A |