GEDI02_A v001

GEDI L2A Elevation and Height Metrics Data Global Footprint Level


PI: Ralph Dubayah

The GEDI Spatial Querying and Subsetting Quick Guide provides instructions on how to find granules for a region of interest and how to perform spatial and/or layer subsetting of GEDI data accessed from the LP DAAC Data Pool and NASA’s Earthdata Search.

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 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.

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 GEDI01_B 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 (describing canopy vertical structure, for example), and many other interpreted products from the return waveforms. Additional information for the layers can be found in the GEDI Level 2A Dictionary.

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Characteristics

Collection and Granule

Collection

Characteristic Description
CollectionGEDI
DOI10.5067/GEDI/GEDI02_A.001
File Size~7 GB
Temporal ResolutionVaries
Temporal Extent2019-03-25 to Present
Spatial ExtentGlobal (51.6 °N to 51.6 °S Latitude)
Coordinate SystemGeographic Latitude and Longitude
DatumWorld Geodetic System (WGS84)
File FormatHDF5
Geographic Dimensions4.2 km across-track by one full ISS orbit along-track

Granule

Characteristic Description
Number of Science Dataset (SDS) Layers156
Columns/RowsN/A
Pixel Size25 m

Layers

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
beam Beam identifier N/A 16-bit unsigned integer N/A N/A 0 to 12 N/A
channel Channel identifier N/A 8-bit unsigned integer N/A N/A 0 to 6 N/A
degrade_flag Flag indicating degraded state of pointing and/or positioning information N/A 8-bit unsigned integer N/A N/A 0, 1 N/A
delta_time Time delta since Jan 1 00:00 2018 Seconds 64-bit floating point N/A N/A N/A N/A
digital_elevation_model TanDEM-X elevation at GEDI footprint location Meters 32-bit floating point N/A N/A N/A N/A
elev_highestreturn Elevation of highest detected return relative to reference ellipsoid Meters 32-bit floating point N/A N/A -1000.0 to 25000.0 N/A
elev_lowestmode Elevation of center of lowest mode relative to reference ellipsoid Meters 32-bit floating point N/A N/A -1000.0 to 25000.0 N/A
elevation_bias_flag Elevations potentially affected by 4bin (~60 cm) ranging error N/A 8-bit unsigned integer N/A N/A 0, 1 N/A
elevation_bin0_error Error in elevation of bin 0 Meters 32-bit floating point N/A N/A -1000 to 25000 N/A
energy_total Integrated counts in the return waveform relative to the mean noise level Number 32-bit floating point N/A N/A -5000 to 5000000 N/A
lat_highestreturn Latitude of highest detected return Degree 64-bit floating point N/A N/A -55 to 55 N/A
lat_lowestmode Latitude of center of lowest mode Degree 64-bit floating point N/A N/A -55 to 55 N/A
latitude_bin0_error Error in latitude of bin 0 Degree 32-bit floating point N/A N/A N/A N/A
lon_highestreturn Longitude of highest detected return Degree 64-bit floating point N/A N/A -180 to 180 N/A
lon_lowestmode Longitude of center of lowest mode Degree 64-bit floating point N/A N/A -180 to 180 N/A
longitude_bin0_error Error on longitude_bin0 Degree 32-bit floating point N/A N/A N/A N/A
master_frac Master time, fractional part Seconds 64-bit floating point N/A N/A N/A N/A
master_int Master time, integer part Seconds 32-bit unsigned integer N/A N/A N/A N/A
mean_sea_surface Mean sea surface height above the WGS84 ellipsoid, includes the geoid Meters 32-bit floating point N/A N/A N/A N/A
num_detectedmodes Number of detected modes in rxwaveform N/A 8-bit unsigned integer N/A N/A N/A N/A
quality_flag Flag simplifying selection of most useful data Quality Flag 8-bit unsigned integer N/A N/A 0, 1 N/A
rh Relative height metrics at 1% interval cm 32-bit floating point N/A N/A -213 to 213 N/A
selected_algorithm Identifier of algorithm selected as identifying the lowest non-noise mode N/A 8-bit unsigned integer N/A N/A 1 to 6 N/A
selected_mode Identifier of mode selected as lowest non-noise mode N/A 8-bit unsigned integer N/A N/A 0 to 20 N/A
sensitivity Maxmimum canopy cover that can be penetrated N/A 32-bit floating point N/A N/A 0, 1 N/A
shot_number Shot number N/A 64-bit unsigned integer N/A N/A N/A N/A
solar_azimuth Solar azimuth N/A 32-bit floating point N/A N/A N/A N/A
solar_elevation Solar elevation N/A 32-bit floating point N/A N/A N/A N/A
surface_flag Indicates elev_lowestmode is within 300 m of DEM or MSS Class Flag 8-bit unsigned integer N/A N/A 0, 1 N/A
l2a_alg_count Number of L2A algorithm runs present in file N/A 8-bit unsigned integer N/A N/A 0 to 10 N/A
elev_highestreturn_aN Elevation of the highest return detected using algorithm N, relative to reference ellipsoid Meters 32-bit floating point N/A N/A -1000 to 25000 N/A
elev_lowestmode_aN Elevation of the center of the lowest mode detected using algorithm N, relative to reference ellipsoid Meters 32-bit floating point N/A N/A -1000 to 25000 N/A
elev_lowestreturn_aN Elevation of lowest return detected using algorithm N, relative to reference ellipsoid Meters 32-bit floating point N/A N/A -1000 to 25000 N/A
elevation_1gfit Elevation corresponding to the center of a single Gaussian fit to the waveform, relative to reference ellipsoid Meters 32-bit floating point N/A N/A -1000 to 25000 N/A
elevs_allmodes_aN Elevations of all modes detected using algorithm N, relative to reference ellipsoid Meters 32-bit floating point N/A N/A -1000 to 25000 N/A
energy_lowestmode_aN Energy of lowest mode, detected using algorithm N, in the waveform above the mean noise level Number 32-bit floating point N/A N/A -5000 to 5000000 N/A
lat_highestreturn_aN Latitude of the highest return detected using algorithm N Degree 64-bit floating point N/A N/A -55 to 55 N/A
lat_lowestmode_aN Latitude of the center of the lowest mode detected using algorithm N Degree 64-bit floating point N/A N/A -55 to 55 N/A
lat_lowestreturn_aN Latitude of the lowest return detected using algorithm N Degree 64-bit floating point N/A N/A -55 to 55 N/A
latitude_1gfit Latitude corresponding to the center of a single Gaussian fit to the waveform Degree 64-bit floating point N/A N/A -55 to 55 N/A
lats_allmodes_aN Latitudes of all modes detected using algorithm N Degree 64-bit floating point N/A N/A -55 to 55 N/A
lon_highestreturn_aN Longitude of the highest return detected using algorithm N Degree 64-bit floating point N/A N/A -180 to 180 N/A
lon_lowestmode_aN Longitude of the center of lowest mode detected using algorithm N Degree 64-bit floating point N/A N/A -180 to 180 N/A
lon_lowestreturn_aN Longitude of lowest return detected using algorithm N Degree 64-bit floating point N/A N/A -180 to 180 N/A
longitude_1gfit Longitude corresponding to the center of a single Gaussian fit to the waveform Degree 64-bit floating point N/A N/A -180 to 180 N/A
lons_allmodes_aN Longitudes of all modes detected using algorithm N Degree 64-bit floating point N/A N/A -180 to 180 N/A
num_detectedmodes_aN Number of detected modes detected using algorithm N N/A 8-bit unsigned integer N/A N/A 0 to 20 N/A
quality_flag_aN Flag simplifying selection of most useful data Quality Flag 8-bit unsigned integer N/A N/A 0, 1 N/A
rh_aN Relative height metrics at 1% intervals using algorithm N cm 16-bit signed integer N/A N/A -213 to 213 N/A
sensitivity_aN Maxmimum canopy cover, using algorithm N, that can be penetrated considering the SNR of the waveform N/A 32-bit floating point N/A N/A 0, 1 N/A
stale_return_flag Flag indicating return signal above detection threshold was not detected Class Flag 8-bit unsigned integer N/A N/A 0, 1 N/A
landsat_treecover Tree cover in the year 2010, defined as canopy closure for all vegetation taller than 5 m in height as a percentage per output grid cell Percent 64-bit floating point -9999 N/A N/A N/A
modis_treecover Percent tree cover from MODIS MOD44B V6 data Percent 64-bit floating point -9999 N/A N/A N/A
modis_treecover_sd Percent tree cover standard deviation from MODIS MOD44B V6 data Percent 64-bit floating point -9999 N/A N/A N/A
modis_nonvegetated Percent non-vegetated from MODIS MOD44B V6 data Percent 64-bit floating point -9999 N/A N/A N/A
modis_nonvegetated_sd Percent non-vegetated standard deviation from MODIS MOD44B V6 data Percent 64-bit floating point -9999 N/A N/A N/A
rx_gamplitude Amplitude of single Gaussian fit to the rxwaveform Number 32-bit floating point N/A N/A 0 to 4096 N/A
rx_gamplitude_error Error in ampltiude estimate for single Gaussian fit to the rxwaveform Number 32-bit floating point N/A N/A 0 to 4096 N/A
rx_gbias Bias estimated in fitting a single Gaussian to the rxwaveform Number 32-bit floating point N/A N/A 0 to 350 N/A
rx_gbias_error Error on rx_gbias parameter estimate Number 32-bit floating point N/A N/A 0 to 350 N/A
rx_gchisq Chi-squared value of Gaussian fit to the rxwaveform N/A 32-bit floating point N/A N/A 0 to 10000 N/A
rx_gflag Gaussian fit status flag (no further improvement) Class Flag 8-bit unsigned integer N/A N/A 0 to 9 N/A
rx_giters Number of iterations to converge Gaussian fit to rxwaveform N/A 16-bit unsigned integer N/A N/A 1 to 100 N/A
rx_gloc Location (mean) of the Gaussian fit to the rxwaveform Nanoseconds 32-bit floating point N/A N/A 0 to 1420 N/A
rx_gloc_error Error on rx_gloc parameter estimate Nanoseconds 32-bit floating point N/A N/A 0 to 1420 N/A
rx_gwidth Width (1 sigma) of the Gaussian fit to the rxwaveform Nanoseconds 32-bit floating point N/A N/A 0 to 1420 N/A
rx_gwidth_error Error on rx_gwidth parameter estimate Nanoseconds 32-bit floating point N/A N/A 0 to 300 N/A
mpfit_max_func_evals Maximum number of function evalutions allowed for fitting the Gaussian/extended Gaussian to the rxwaveform N/A 64-bit signed integer N/A N/A 0 to 100 N/A
mpfit_maxiters Maximum number of iterations allowed for fitting the Gaussian/extended Gaussian to the rxwaveform N/A 64-bit signed integer N/A N/A 0 to 100 N/A
mpfit_tolerance Convergence tolerance when fitting the Gaussian/extended Gaussian to the rxwaveform N/A 64-bit floating point N/A N/A 0, 1 N/A
rx_constraint_gamplitude_lower Lower allowable limit for the RX Gaussian fit amplitude Number 64-bit floating point N/A N/A 0 to 4096 N/A
rx_constraint_gamplitude_upper Upper allowable limit for the RX Gaussian fit amplitude Number 64-bit floating point N/A N/A 0 to 4096 N/A
rx_constraint_gloc_lower Lower allowable limit for the RX Gaussian fit location Nanoseconds 64-bit floating point N/A N/A 0 to 1420 N/A
rx_constraint_gloc_upper Upper allowable limit for the RX Gaussian fit location Nanoseconds 64-bit floating point N/A N/A 0 to 1420 N/A
rx_constraint_gwidth_lower Lower allowable limit for the RX Gaussian fit width Nanoseconds 64-bit floating point N/A N/A 0 to 1000 N/A
rx_constraint_gwidth_upper Upper allowable limit for the RX Gaussian fit width Nanoseconds 64-bit floating point N/A N/A 0 to 1000 N/A
rx_estimate_bias If set to 1, a bias was estimated as part of the Gaussian fit; set to 0 otherwise N/A 32-bit signed integer N/A N/A 0, 1 N/A
rx_mean_noise_level If amplitude is less than this value, no Gaussian fitting is performed to the rxwaveform Number 64-bit floating point N/A N/A 0 to 350 N/A
rx_smoothwidth Smoothing width to apply to waveforms before Gaussian fitting Nanoseconds 64-bit floating point N/A N/A 0 to 50 N/A
mean Mean noise estimate used in RX waveform interpretation algorithm Number 32-bit floating point N/A N/A 0 to 4096 N/A
mean_64kadjusted Average amplitude within 10 km search window with energy from rxwaveform removed Number 32-bit floating point N/A N/A 0 to 1000000 N/A
ocean_calibration_shot_flag Flag indicating return suitable for use in sensor parameter estimation Class Flag 8-bit unsigned integer N/A N/A 0, 1 N/A
quality_flag Flag indicating likely invalid waveform (1=valid, 0=invalid) Quality Flag 8-bit unsigned integer N/A N/A 0, 1 N/A
rx_assess_flag Flags indicating various error conditions possible in rxwaveform Class Flag 16-bit unsigned integer N/A N/A 0, 1 N/A
rx_clipbin0 Location of first waveform sample exceeding clip amplitude Number 16-bit unsigned integer N/A N/A 0 to 1420 N/A
rx_clipbin_count Number of consecutive waveform samples affected by clipping Number 16-bit unsigned integer N/A N/A 0 to 1420 N/A
rx_energy Total energy of rxwaveform, mean noise removed Number 32-bit floating point N/A N/A -1000 to 1000000 N/A
rx_maxamp Maximum amplitude of rxwaveform relative to mean noise level Number 32-bit floating point N/A N/A N/A N/A
rx_maxpeakloc Waveform sample where maximum amplitude of waveform occurs Number 16-bit unsigned integer N/A N/A 1 to 1420 N/A
sd_corrected Noise standard deviation, corrected for odd/even digitizer bin errors based on pre-launch calibrations Number 32-bit floating point N/A N/A 0 to 20 N/A
shot_number Shot number N/A 64-bit unsigned integer N/A N/A N/A N/A
rx_ampbounds_ll Lower limit used for pulse amplitude flag Number 64-bit floating point N/A N/A 0 to 4096 N/A
rx_ampbounds_ul Upper limit used for pulse amplitude flag Number 64-bit floating point N/A N/A 0 to 4096 N/A
rx_clipamp Ampltiude above which clipping may occur Number 64-bit floating point N/A N/A 0 to 4096 N/A
rx_pulsethresh Amplitude used to flag low amplitude return waveforms Number 64-bit floating point N/A N/A 0 to 4096 N/A
rx_ringthresh Multipler on noise stddev to detect presence of ringing below the mean in the pulse Number 64-bit floating point N/A N/A 0 to 4096 N/A
smoothing_width_locs Used in debugging only Nanoseconds 64-bit floating point N/A N/A 0 to 1420 N/A
back_threshold Threshold used to detect lowest elevation return energy Number 32-bit floating point N/A N/A 0 to 4096 N/A
botloc Waveform sample location of lowest detected return energy relative to bin0 of waveform Number 32-bit floating point N/A N/A 0 to 1420 N/A
botloc_amp Amplitude at lowest detected energy return Number 32-bit floating point N/A N/A 0 to 4096 N/A
energy_sm Total energy of smoothed waveform Number 32-bit floating point N/A N/A -1000 to 100000 N/A
front_threshold Threshold used to detect highest elevation return energy Number 32-bit floating point N/A N/A 0 to 4096 N/A
lastmodeenergy Energy in lowest detected mode Number 32-bit floating point N/A N/A -1000 to 100000 N/A
mean Mean noise level used in algorithm Number 32-bit floating point N/A N/A 0 to 4096 N/A
mean_sm Mean noise level after smoothing Number 32-bit floating point N/A N/A 0 to 4096 N/A
min_detection_energy Integrated area of the computed minimally-detectable Gaussian Number 32-bit floating point N/A N/A -1000 to 100000 N/A
min_detection_threshold Detection threshold used to compute the minimally detected gaussian Number 32-bit floating point N/A N/A 0 to 1420 N/A
peak Peak amplitude of raw waveform Number 32-bit floating point N/A N/A -100 to 1420 N/A
pk_sm Peak ampltiude of smoothed waveform Number 32-bit floating point N/A N/A -100 to 1420 N/A
rx_algrunflag Flag indicating signal was detected and algorithm ran successfully Class Flag 8-bit unsigned integer N/A N/A 0, 1 N/A
rx_cumulative Waveform bin numbers of integer percents of integrated energy from cumulative waveform Nanoseconds 32-bit floating point N/A N/A 0 to 1420 N/A
rx_iwaveamps Fraction of integrated waveform at location of each detected mode Number 32-bit floating point N/A N/A 0, 1 N/A
rx_modeamps Amplitudes of each detected mode within waveform Number 32-bit floating point N/A N/A -100 to 1420 N/A
rx_modeenergytobotloc Total energy from the center of each detected waveform mode to botloc Number 32-bit floating point N/A N/A -1000 to 1000000 N/A
rx_modelocalenergy Energy between +/- 8 samples of each detected mode, mean noise level removed Number 32-bit floating point N/A N/A -1000 to 1000000 N/A
rx_modelocalenergyabovemean Energy between +/- 8 samples of each detected mode Number 32-bit floating point N/A N/A -1000 to 1000000 N/A
rx_modelocalslope Signal trend within +/- 8 samples of each detected mode Number 32-bit floating point N/A N/A -100 to 100 N/A
rx_modelocs Sample numbers of each detected mode (relative to bin 0 of waveform) Nanoseconds 32-bit floating point N/A N/A 0 to 1420 N/A
rx_modewidths 1 sigma width estimates of each detected mode in waveform Nanoseconds 32-bit floating point N/A N/A 0 to 700 N/A
rx_nummodes Number of modes detected in waveform Nanoseconds 8-bit unsigned integer N/A N/A N/A N/A
sd_sm Noise standard deviation of the smoothed waveform Number 32-bit floating point N/A N/A 0 to 100 N/A
search_end Sample number indicating end of signal search Nanoseconds 32-bit floating point N/A N/A 0 to 1420 N/A
search_start Sample number indicating start of signal search Nanoseconds 32-bit floating point N/A N/A 0 to 1420 N/A
selected_mode Identifier of mode selected as lowest non-noise mode N/A 8-bit unsigned integer N/A N/A 0 to 40 N/A
selected_mode_flag Flag indicating status of selected_mode Class Flag 8-bit unsigned integer N/A N/A 0 to 4 N/A
shot_number Shot number N/A 64-bit unsigned integer N/A N/A N/A N/A
smoothwidth Width of Gaussian function used to smooth noise sections of waveforms Nanoseconds 32-bit floating point N/A N/A 0 to 20 N/A
smoothwidth_zcross Width of Gaussian function used to smooth waveform between botloc and toploc Nanoseconds 32-bit floating point N/A N/A 0 to 20 N/A
stddev Noise standdard deviation used in algorithm Number 32-bit floating point N/A N/A 0 to 4096 N/A
toploc Sample number of highest detected return Number 32-bit floating point N/A N/A 0 to 1420 N/A
toploc_miss Flag indicating algorithm didn't detect valid toploc value Class Flag 8-bit unsigned integer N/A N/A 0, 1 N/A
zcross Sample number of center of lowest mode above noise level Nanoseconds 32-bit floating point N/A N/A 0 to 1420 N/A
zcross0 Location of center of highest mode above noise level relative to bin0 of waveform Nanoseconds 32-bit floating point N/A N/A 0 to 1420 N/A
zcross_amp Amplitude of smoothed waveform at lowest detected mode Number 32-bit floating point N/A N/A 0 to 4096 N/A
zcross_localenergy Energy of last mode above local slope Number 32-bit floating point N/A N/A -100 to 10000 N/A
amp_thresh Final ground return pulse selection parameter Number 64-bit floating point N/A N/A 0 to 4096 N/A
ampval_limit2 Final ground return pulse selection parameter Number 64-bit floating point 0, 148 N/A 0 to 4096 N/A
ampval_limit3 Final ground return pulse selection parameter Number 64-bit floating point 0, 149 N/A 0 to 4096 N/A
botlocdist_limit1 Final ground return pulse selection parameter Nanoseconds 64-bit floating point 0, 150 N/A 0 to 50 N/A
botlocdist_limit2 Final ground return pulse selection parameter Nanoseconds 64-bit floating point 0, 151 N/A 0 to 50 N/A
botlocdist_limit3 Final ground return pulse selection parameter Nanoseconds 64-bit floating point 0, 152 N/A 0 to 50 N/A
cumulative_energy_minimum Final ground return pulse selection parameter Number 64-bit floating point 0, 153 N/A 0, 1 N/A
cumulative_energy_thresh Final ground return pulse selection parameter Number 64-bit floating point 0, 154 N/A 0, 1 N/A
enable_select_mode Final ground return pulse selection parameter N/A 32-bit signed integer 0, 155 N/A 0, 1 N/A
energy_thresh Final ground return pulse selection parameter Number 64-bit floating point 0, 156 N/A 0 to 1000 N/A
preprocessor_threshold Initial search threshold multiplier to detect signal start and end N/A 64-bit floating point 0, 157 N/A 0 to 100 N/A
pulse_sep_thresh Final ground return pulse selection parameter Nanoseconds 64-bit floating point 0, 158 N/A 0 to 100 N/A
rx_back_threshold Noise stddev multiplier used to detect the lowest elevation signal N/A 64-bit floating point 0, 159 N/A 0 to 100 N/A
rx_front_threshold Noise stddev multiplier used to detect the highest elevation signal N/A 64-bit floating point 0, 160 N/A 0 to 100 N/A
rx_max_mode_count Maximum number of modes saved for each footprint N/A 64-bit signed integer 0, 161 N/A 0 to 40 N/A
rx_searchsize In combination with preprocessor_threshold, used to define area of waveform to be searched by algorithm Nanoseconds 64-bit floating point 0, 162 N/A 0 to 500 N/A
rx_sentinel_location Location of sentinel pulse used by sensitivity algorithm Nanoseconds 64-bit floating point 0, 163 N/A 0 to 300 N/A
rx_smoothing_width_locs Width of Guassian pulse convolved with waveform to reduce noise prior to toploc/botloc identification Nanoseconds 64-bit floating point 0, 164 N/A 0 to 30 N/A
rx_smoothing_width_zcross Width of Guassian pulse convolved with waveform to reduce noise prior to pulse mode identification Nanoseconds 64-bit floating point 0, 165 N/A 0 to 30 N/A
rx_subbin_resolution Factor of increased vertical resolution relative to native waveform resolution (~0.15 m) N/A 64-bit signed integer 0, 166 N/A 0 to 10 N/A
rx_use_fixed_thresholds Noise stddev multipliers used to detect the highest and lowest elevation returns N/A 32-bit signed integer 0, 167 N/A 0, 1 N/A

All beams included in the data product will contain the same sets of Science Dataset (SDS) layers.

Product Quality

Quality information is provided in section 6 of the User Guide.

Known Issues

  • Known Issues: Section 7 of the User Guide provides additional information on 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).

Documentation

Using the Data

Access Data

Citation

DOI: 10.5067/GEDI/GEDI02_A.001

About the Image

Elevation tract from the GEDI02_A Product.

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