getLevel1BGeo: Get GEDI Full Waveform Geolocations (GEDI Level1B)

In rGEDI: NASA's Global Ecosystem Dynamics Investigation (GEDI) Data Visualization and Processing

Description

This function extracts Pulse Full Waveform Geolocations from GEDI Level1B data

Usage

getLevel1BGeo(level1b, select)

Arguments

level1b	A GEDI Level1B object (output of readLevel1B function). An S4 object of class "gedi.level1b".
select	A character vector specifying the fields to extract from GEDI Level1B data. If NULL, by default it will extract latitude_bin0, latitude_lastbin, longitude_bin0, longitude_lastbin, and shot_number. See details for more options.

Details

Additional fields to be extracted from GEDI level 1B:

• all_samples_sum Sum of all values within the 10 km range window.

• beam Beam number Number.

• channel Channel number.

• master_frac Master time, fractional part.

• master_int Master time, integer part.

• noise_mean_corrected Noise mean.

• noise_stddev_corrected Corrected noise standard deviation.

• nsemean_even Noise mean of the beam's detector channel from even sub-converter.

• nsemean_odd Noise mean of the beam's odd sub-converter.

• rx_energy Integrated energy in receive (RX) waveform after subtracting the noise mean.

• rx_offset Time interval from first stored sample to first downloaded RX sample.

• rx_open Time interval from time 0 to first stored RX sample.

• rx_sample_count The number of sample intervals (elements) in each RX waveform.

• rx_sample_start_index The index in the rxwaveform dataset of the first element of each RX waveform starting at 1.

• selection_stretchers_x Commanded number of samples added to the algorithm section on the left.

• selection_stretchers_y Commanded number of samples added to the algorithm section on the right.

• shot_number Unique shot identifier.

• stale_return_flag Indicates that a "stale" cue point from the coarse search algorithm is being used.

• th_left_used Count values for the left threshold used in fine search where two consecutive points at or above this value indicate pulse detection.

• tx_egamplitude Amplitude of the extended Gaussian fit to the transmit (TX) waveform.

• tx_egamplitude_error Error on tx_egamplitude.

• tx_egbias Bias of the extended Gaussian fit to the TX waveform.

• tx_egbias_error Error on tx_egbias.

• tx_egflag Extended Gaussian fit status flag.

• tx_eggamma Gamma value of the extended Gaussian fit to the TX waveform.

• tx_eggamma_error Error on tx_eggamma.

• tx_egsigma Sigma of the extended Gaussian fit to the TX waveform.

• tx_egsigma_error Error on tx_egsigma.

• tx_gloc Location (mean) of the Gaussian fit to the TX waveform.

• tx_gloc_error Error on tx_gloc.

• tx_pulseflag Set to 1 if a pulse is detected in the TX waveform.

• tx_sample_count The number of sample intervals (elements) in each transmit waveform.

• tx_sample_start_index The index in the rxwaveform dataset of the first element of each RX waveform starting at 1.

• altitude_instrument Height of the instrument diffractive optical element (DOE) above the WGS84 ellipsoid.

• altitude_instrument_error Error on altitude_instrument.

• bounce_time_offset_bin0 The difference between the TX time and the time at the start of the RX window.

• bounce_time_offset_bin0_error Error on bounce_time_offset_bin0.

• bounce_time_offset_lastbin The difference between the TX time and the time at the end of the RX window.

• bounce_time_offset_lastbin_error Error on bounce_time_offset_lastbin.

• degrade Greater than zero if the shot occurs during a degrade period, zero otherwise.

• delta_time Transmit time of the shot, measured in seconds since 2018-01-01.

• digital_elevation_model Digital elevation model height above the WGS84 ellipsoid.

• elevation_bin0 Height of the start of the RX window, relative to the WGS-84 ellipsoid.

• elevation_bin0_error Error on elevation_bin0.

• elevation_lastbin Height of the end of the RX window, relative to the WGS-84 ellipsoid.

• elevation_lastbin_error Error on elevation_lastbin.

• latitude_bin0 Latitude of the start of the RX window.

• latitude_bin0_error Error on latitude_bin0.

• latitude_lastbin Latitude of the end of the RX window.

• latitude_lastbin_error Error on latitude_lastbin.

• latitude_instrument Latitude of the instrument diffractive optical element (DOE) at laser transmit time.

• latitude_instrument_error Error on latitude_instrument.

• local_beam_azimuth Azimuth of the unit pointing vector for the laser in the local East, North, Up (ENU) frame.

• local_beam_azimuth_error Error on local_beam_azimuth.

• local_beam_elevation Elevation of the unit pointing vector for the laser in the local ENU frame.

• local_beam_elevation_error Error on local_beam_elevation.

• longitude_bin0 Longitude of the start of the RX window.

• longitude_bin0_error Error on longitude_bin0.

• longitude_lastbin Longitude of the end of the RX window.

• longitude_lastbin_error Error on longitude_lastbin.

• longitude_instrument Longitude of the instrument diffractive optical element (DOE) at laser transmit time.

• longitude_instrument_error Error on longitude_instrument.

• mean_sea_surface Mean sea surface height above the WGS84 ellipsoid, includes the geoid .

• neutat_delay_derivative_bin0 Change in neutral atmospheric delay per height change for the start of the RX window.

• neutat_delay_derivative_lastbin Change in neutral atmospheric delay per height change for the end of the RX window.

• neutat_delay_total_bin0 Total neutral atmosphere delay correction (wet+dry) from the TX pulse to the start of the RX window.

• neutat_delay_total_lastbin Total neutral atmosphere delay correction (wet+dry) from the TX pulse to the end of the RX window.

• range_bias_correction The range bias applied to the range measurement.

• shot_number Unique shot identifier Number.

• solar_azimuth The azimuth of the sun position vector.

• solar_elevation The elevation of the sun position vector.

• surface_type Flags describing which surface types.

• dynamic_atmosphere_correction Dynamic Atmospheric Correction (DAC) includes inverted barometer (IB) effect.

• geoid Geoid height above WGS-84 reference ellipsoid.

• tide_earth Solid Earth tides.

• tide_load Load Tide - Local displacement due to Ocean Loading.

• tide_ocean Ocean Tides including diurnal and semi-diurnal, and longerperiod tides.

• tide_ocean_pole Oceanic surface rotational deformation due to polar motion.

• tide_pole Solid Earth Pole Tide. Rotational deformation due to polar motion.

Value

Returns an S4 object of class data.table-class containing the GEDI Full Waveform Geolocations

See Also

https://lpdaac.usgs.gov/products/gedi01_bv001/

Examples

# specify the path to GEDI level1B data (zip file)
outdir = tempdir()
level1B_fp_zip <- system.file("extdata",
                  "GEDI01_B_2019108080338_O01964_T05337_02_003_01_sub.zip",
                  package="rGEDI")

# Unzipping GEDI level1B data
level1Bpath <- unzip(level1B_fp_zip,exdir = outdir)

# Reading GEDI level1B data (h5 file)
level1b<-readLevel1B(level1Bpath=level1Bpath)

# Extracting GEDI level1B geolocations
level1bGeo<-getLevel1BGeo(level1b,select=c("elevation_bin0", "elevation_lastbin"))
head(level1bGeo)

close(level1b)

rGEDI documentation built on Jan. 19, 2021, 3:01 p.m.