GEDI01_B v001

GEDI L1B Geolocated Waveform Data Global Footprint Level


PI: Ralph Dubayah

Spatial querying of GEDI files is now available with the GEDI Finder web service. Additional information can be found in the GEDI Finder User Guide.

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 GEDI Level 1B Geolocated Waveforms product (GEDI01_B) provides geolocated corrected and smoothed waveforms, geolocation parameters, and geophysical corrections for each laser shot for all eight GEDI beams. GEDI01_B data are created by geolocating the GEDI01_A raw waveform data. The GEDI01_B product is provided in HDF5 format and has a spatial resolution (average footprint) of 25 meters.

The GEDI01 B data product contains 85 layers for each of the eight beams including the geolocated corrected and smoothed waveform datasets and parameters and the accompanying ancillary, geolocation, and geophysical correction. Additional information can be found in the GEDI L1B Product Data Dictionary.

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Characteristics

Collection and Granule

Collection

Characteristic Description
CollectionGEDI
DOI10.5067/GEDI/GEDI01_B.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) Layers85
Columns/RowsN/A
Pixel Size25 m

Layers

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
all_samples_sum Sum of all values within the 10 km range window Number 32-bit unsigned integer N/A N/A N/A N/A
beam Beam number Number 16-bit unsigned integer N/A N/A 0 to 15 N/A
channel Channel number Number 8-bit unsigned integer N/A N/A 0 to 7 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
noise_mean_corrected Noise mean Number 64-bit floating point N/A N/A N/A N/A
noise_stddev_corrected Corrected noise standard deviation Number 64-bit floating point N/A N/A N/A N/A
nsemean_even Noise mean of the beam's detector channel from even sub-converter Number 32-bit floating point N/A N/A N/A N/A
nsemean_odd Noise mean of the beam's odd sub-converter Number 32-bit floating point N/A N/A N/A N/A
rx_energy Integrated energy in receive (RX) waveform after subtracting the noise mean Nanoseconds 64-bit floating point N/A N/A N/A N/A
rx_offset Time interval from first stored sample to first downloaded RX sample Nanoseconds 16-bit unsigned integer N/A N/A N/A N/A
rx_open Time interval from time 0 to first stored RX sample Nanoseconds 32-bit unsigned integer N/A N/A N/A N/A
rx_sample_count The number of sample intervals (elements) in each RX waveform Number 16-bit unsigned integer N/A N/A N/A N/A
rx_sample_start_index The index in the rxwaveform dataset of the first element of each RX waveform starting at 1 Number 64-bit unsigned integer N/A N/A N/A N/A
rxwaveform The corrected receive RX waveforms using rx_sample_count and rx_sample_start_index to identify the location of each waveform Number 32-bit floating point N/A N/A N/A N/A
selection_stretchers_x Commanded number of samples added to algorithm section on the left Nanoseconds 16-bit unsigned integer N/A N/A N/A N/A
selection_stretchers_y Commanded number of samples added to algorithm section on the right Nanoseconds 16-bit unsigned integer N/A N/A N/A N/A
shot_number Unique shot identifier Number 64-bit unsigned integer N/A N/A N/A N/A
stale_return_flag Indicates that a "stale" cue point from the coarse search algorithm is being used Class Flag 8-bit unsigned integer N/A N/A N/A N/A
th_left_used Count values for left threshold used in fine search where two consecutive points at or above this value indicates pulse detection Number 16-bit unsigned integer N/A N/A N/A N/A
tx_egamplitude Amplitude of the extended Gaussian fit to the transmit (TX) waveform Number 64-bit floating point N/A N/A N/A N/A
tx_egamplitude_error Error on tx_egamplitude Number 32-bit floating point N/A N/A N/A N/A
tx_egbias Bias of the extended Gaussian fit to the TX waveform Number 32-bit floating point N/A N/A N/A N/A
tx_egbias_error Error on tx_egbias Number 32-bit floating point N/A N/A N/A N/A
tx_egflag Extended Gaussian fit status flag Class Flag 8-bit unsigned integer N/A N/A 1 to 8 N/A
tx_eggamma Gamma value of the extended Gaussian fit to the TX waveform N/A 32-bit floating point N/A N/A N/A N/A
tx_eggamma_error Error on tx_eggamma N/A 32-bit floating point N/A N/A N/A N/A
tx_egsigma Sigma of the extended Gaussian fit to the TX waveform Nanoseconds 32-bit floating point N/A N/A N/A N/A
tx_egsigma_error Error on tx_egsigma Nanoseconds 32-bit floating point N/A N/A N/A N/A
tx_gloc Location (mean) of the Gaussian fit to the TX waveform Nanoseconds 32-bit floating point N/A N/A N/A N/A
tx_gloc_error Error on tx_gloc Nanoseconds 32-bit floating point N/A N/A N/A N/A
tx_pulseflag Set to 1 if a pulse is detected in the TX waveform Class Flag 8-bit unsigned integer N/A N/A N/A N/A
tx_sample_count The number of sample intervals (elements) in each transmit waveform Number 16-bit unsigned integer N/A N/A N/A N/A
tx_sample_start_index The index in the rxwaveform dataset of the first element of each RX waveform starting at 1 Number 64-bit unsigned integer N/A N/A N/A N/A
txwaveform The corrected TX waveforms using tx_sample_count and tx_sample_start_index to identify the location of each waveform Number 32-bit floating point N/A N/A N/A N/A
master_time_epoch Number of GPS seconds between the GPS epoch (1980-01-06T00:00:00Z) and the GEDI epoch (2018-01-01T00:00:00Z) Seconds 64-bit floating point N/A N/A N/A N/A
mean_samples Averaging window (shots) for non-repeated odd-even measurements from housekeeping Number 64-bit signed integer N/A N/A N/A N/A
smoothing_width The 1-sigma width of the gaussian kernel used to smooth the corrected waveform Nanoseconds 64-bit floating point N/A N/A N/A N/A
altitude_instrument Height of the instrument diffractive optical element (DOE) above the WGS84 ellipsoid Meters 64-bit floating point N/A N/A N/A N/A
altitude_instrument_error Error on altitude_instrument Meters 32-bit floating point N/A N/A N/A N/A
bounce_time_offset_bin0 The difference between the TX time and the time at the start of the RX window Seconds 64-bit floating point N/A N/A N/A N/A
bounce_time_offset_bin0_error Error on bounce_time_offset_bin0 Seconds 32-bit floating point N/A N/A N/A N/A
bounce_time_offset_lastbin The difference between the TX time and the time at the end of the RX window Seconds 64-bit floating point N/A N/A N/A N/A
bounce_time_offset_lastbin_error Error on bounce_time_offset_lastbin Seconds 64-bit floating point N/A N/A N/A N/A
degrade Greater than zero if the shot occurs during a degrade period, zero otherwise Class Flag 8-bit signed integer N/A N/A N/A N/A
delta_time Transmit time of the shot, measured in seconds since 2018-01-01 Seconds 64-bit floating point N/A N/A N/A N/A
digital_elevation_model Digital elevation model height above the WGS84 ellipsoid Meters 32-bit floating point -9999 N/A N/A N/A
elevation_bin0 Height of the start of the RX window, relative to the WGS-84 ellipsoid Meters 64-bit floating point N/A N/A N/A N/A
elevation_bin0_error Error on elevation_bin0 Meters 32-bit floating point N/A N/A N/A N/A
elevation_lastbin Height of the end of the RX window, relative to the WGS-84 ellipsoid Meters 64-bit floating point N/A N/A N/A N/A
elevation_lastbin_error Error on elevation_lastbin Meters 32-bit floating point N/A N/A N/A N/A
latitude_bin0 Latitude of the start of the RX window Degree 64-bit floating point N/A N/A N/A N/A
latitude_bin0_error Error on latitude_bin0 Degree 32-bit floating point N/A N/A N/A N/A
latitude_lastbin Latitude of the end of the RX window Degree 64-bit floating point N/A N/A N/A N/A
latitude_lastbin_error Error on latitude_lastbin Degree 32-bit floating point N/A N/A N/A N/A
latitude_instrument Latitude of the instrument diffractive optical element (DOE) at laser transmit time Degree 64-bit floating point N/A N/A N/A N/A
latitude_instrument_error Error on latitude_instrument Degree 32-bit floating point N/A N/A N/A N/A
local_beam_azimuth Azimuth of the unit pointing vector for the laser in the local East, North, Up (ENU) frame Radians 32-bit floating point N/A N/A N/A N/A
local_beam_azimuth_error Error on local_beam_azimuth Radians 32-bit floating point N/A N/A N/A N/A
local_beam_elevation Elevation of the unit pointing vector for the laser in the local ENU frame Radians 32-bit floating point N/A N/A N/A N/A
local_beam_elevation_error Error on local_beam_elevation Radians 32-bit floating point N/A N/A N/A N/A
longitude_bin0 Longitude of the start of the RX window Degree 64-bit floating point N/A N/A N/A N/A
longitude_bin0_error Error on longitude_bin0 Degree 32-bit floating point N/A N/A N/A N/A
longitude_lastbin Longitude of the end of the RX window Degree 64-bit floating point N/A N/A N/A N/A
longitude_lastbin_error Error on longitude_lastbin Degree 32-bit floating point N/A N/A N/A N/A
longitude_instrument Longitude of the instrument diffractive optical element (DOE) at laser transmit time Degree 64-bit floating point N/A N/A N/A N/A
longitude_instrument_error Error on longitude_instrument Degree 32-bit floating point 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
neutat_delay_derivative_bin0 Change in neutral atmospheric delay per height change for the start of the RX window m/m 32-bit floating point N/A N/A N/A N/A
neutat_delay_derivative_lastbin Change in neutral atmospheric delay per height change for the end of the RX window m/m 32-bit floating point N/A N/A N/A N/A
neutat_delay_total_bin0 Total neutral atmosphere delay correction (wet+dry) from the TX pulse tothe start of the RX window Meters 32-bit floating point N/A N/A N/A N/A
neutat_delay_total_lastbin Total neutral atmosphere delay correction (wet+dry) from the TX pulse tothe end of the RX window Meters 32-bit floating point N/A N/A N/A N/A
range_bias_correction The range bias applied to the range measurement Meters 32-bit floating point N/A N/A N/A N/A
shot_number Unique shot identifier Number 64-bit unsigned integer N/A N/A N/A N/A
solar_azimuth The azimuth of the sun position vector Degree 32-bit floating point N/A N/A N/A N/A
solar_elevation The elevation of the sun position vector Degree 32-bit floating point N/A N/A N/A N/A
surface_type Flags describing which surface types Class Flag 8-bit signed integer N/A N/A N/A N/A
delta_time Transmit time of the shot Seconds 64-bit floating point N/A N/A N/A N/A
dynamic_atmosphere_correction Dynamic Atmospheric Correction (DAC) includes inverted barometer (IB) effect Meters 32-bit floating point N/A N/A N/A N/A
geoid Geoid height above WGS-84 reference ellipsoid Meters 32-bit floating point N/A N/A -107 to 86 N/A
tide_earth Solid Earth tides Meters 32-bit floating point N/A N/A N/A N/A
tide_load Load Tide - Local displacement due to Ocean Loading cm 32-bit floating point N/A N/A -6 to 0 0.01
tide_ocean Ocean Tides including diurnal and semi-diurnal, and longerperiod tides Meters 32-bit floating point N/A N/A N/A N/A
tide_ocean_pole Oceanic surface rotational deformation due to polar motion mm 32-bit floating point N/A N/A -2 to 2 N/A
tide_pole Solid Earth Pole Tide -- Rotational deformation due to polar motion cm 32-bit floating point N/A N/A -1.5 to 1.5 N/A

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

Known Issues

  • Known Issues: Section 6.1 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 6, 2020 (2020 Day 6).

Documentation

Using the Data

Access Data

Citation

DOI: 10.5067/GEDI/GEDI01_B.001

About the Image

An example of a transmitted and received waveform from the GEDIL01_B Product.

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