LVIS Data Structure (LDS) Version 1.05 Description

Historic Data (1998-2009) Rerelease

Byte Order:

  • All data items are Big Endian unless otherwise noted.

Reference Frame:

  • International Terrestrial Reference Frame (ITRF 2000 / WGS-84 Ellipsoid).

General Notes:

  • A release is comprised of two or more file types sharing a common origin. All files within the release have equal record numbers, and correspond to one another laser shot for shot. (i.e. record 1000 in the .h5 file will be the same laser shot as record 1000 in the .txt file for a given data set)
  • Note: Due to file size issues, some missions have Level2 as a single file and Level1B split into multiple files. The shots are always ordered by day and time, so concatenation of the Level 1B shots will match the Level 2 shots.

Level 1B Geolocated LVIS Waveform (HDF format):

Item Byte Size Format Units Item Description
LFID 4 unsigned longword integer LVIS file identification
shotnumber 4 unsigned longword integer laser shot assigned during collection
azimuth 4 single precision floating point degrees azimuth angle of laser beam
incidentangle 4 single precision floating point degrees off-nadir incident angle of laser beam
range 4 single precision floating point meters distance from the instrument to the ground
date 4 integer UTC date in yyyymmdd format
time 8 double precision floating point seconds UTC decimal seconds of the day
lon0 8 double precision floating point degrees longitude of the highest sample of the waveform (degrees east)
lat0 8 double precision floating point degrees latitude of the highest sample of the waveform (degrees north)
z0 4 single precision floating point meters elevation of the highest sample of the waveform
lon431 [lon351]* 8 double precision floating point degrees longitude of the lowest sample of the waveform (degrees east)
lat431 [lat351]* 8 double precision floating point degrees latitude of the lowest sample of the waveform (degrees north)
z431 [z351]* 4 single precision floating point meters elevation of the lowest sample of the waveform
sigmean 4 single precision floating point counts signal mean noise level, calculated in-flight
txwave 80 byte counts transmit return waveform, 8bits @ 500MHz sample spacing
rxwave 432 [352]* byte counts receive return waveform, 8bits @ 500MHz sample spacing
TOTAL 1100 [940]* bytes per record

*Variables and bitwidths in [brackets] are for data from 1998.



Level 2 Geolocated Surface Elevation and Height Product (ASCII Text format)

Item Byte Size Format Units Item Description
LFID 4 unsigned longword integer LVIS File Identification
shotnumber 4 unsigned longword integer laser shot number assigned during collection
date 4 integer UTC date in yyyymmdd format
time 8 double precision floating point seconds UTC decimal seconds of the day
glon 8 double precision floating point degrees longitude of the lowest detected mode within the waveform (Degrees East)
glat 8 double precision floating point degrees latitude of the lowest detected mode within the waveform (Degrees North)
zg 4 single precision floating point meters mean elevation of the lowest detected mode within the waveform
tlon 8 double precision floating point degrees longitude of the highest detected return (degrees east)
tlat 8 double precision floating point degrees latitude of the highest detected return (degrees north)
zt 4 single precision floating point meters elevation of the highest detected return (i.e., zg + rh100)
RH25 4 single precision floating point meters height (relative to zg) at which 25% of the waveform energy occurs
RH50 4 single precision floating point meters height (relative to zg) at which 50% of the waveform energy occurs
RH75 4 single precision floating point meters height (relative to zg) at which 75% of the waveform energy occurs
RH100 4 single precision floating point meters height (relative to zg) at which 100% of the waveform energy occurs
azimuth 4 single precision floating point degrees true heading bearing from the instrument to the ground spot
incidentangle 4 single precision floating point degrees off nadir angle of the beam path
range 4 single precision floating point meters distance from the instrument to the ground
TOTAL 84 bytes per record

Use the following python script to view Level 1B and Level 2 data products in the LDS v1.0 format. You will need to install the numpy python package in order for this script to work.

read_legacy_lvis.py