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March 2006 Lidar Point Data of Southern California Coastline: Long Beach to US/Mexican Border

This data set contains lidar point data (Geodetic Coordinates) from a strip of Southern California coastline (including water, beach, cliffs, and top of cliffs) from Long Beach to the US/Mexico border. The data set was created by combining data collected using an Optech Inc. Airborne Laser Terrain Mapper (ALTM) 1225 in combination with geodetic quality Global Positioning System (GPS) airborne and ground-based receivers. The Bureau of Economic Geology, the University of Texas at Austin owns and operates an ALTM 1225 system (serial number 99d118). The system was installed in a twin engine Partenavia P-68 (tail number N3832K) owned and operated by Aspen Helicopter, Inc. The lidar data set described by this document was collected on 24 and 25 March 2006; Julian Days 08306 and 08406 (see Lineage, Source_Information, Source_Contribution for pass information). 99d118 instrument settings for these flights were; laser pulse rate: 25kHz, scanner rate: 26Hz, scan angle: +/- 20deg, beam divergence: narrow, altitude: 300-600m AGL, and ground speed: 95-120kts. Two GPS base stations were operating during each day of the survey, Point Loma and San Onofre on 08306 and Seal Beach and San Onofre on 08406 (see Lineage, Source_Information, and Source Contribution for coordinates). Data represented is all points including terrain, vegetation, and structures. This data also contains returns from the water surface. No processing has been done to remove returns from terrain, vegetation, structures or water surfaces.
Cite this dataset when used as a source.
Other Access Online access information not available.
Distribution Formats
  • LAZ
Distributor DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
Dataset Point of Contact Julie Thomas/Randy Bucciarelli
Project Managers
SCBPS/CDIP, Scripps Institution of Oceanography
Documentation links not available.
  • publication: 2006-07-26
Data Presentation Form: Digital image
Dataset Progress Status Complete
Data Update Frequency: As needed
Supplemental Information:
The ALTM 1225 (SN#99d118) lidar instrument has the following specifications: operating altitude = 410-2,000 m AGL; maximum laser pulse rate = 25 kHz; laser scan angle = variable from 0 to +/-20deg from nadir; scanning frequency = variable, 28 Hz at the 20deg scan angle; and beam divergence: narrow = 0.2 milliradian (half angle, 1/e). The ALTM 1225 does not digitize and record the waveform of the laser reflection, but records the range and backscatter intensity of the first and last laser reflection using a constant-fraction discriminator and two Timing Interval Meters (TIM). ALTM elevation points are computed using three sets of data: laser ranges and their associated scan angles, platform position and orientation information, and calibration data and mounting parameters (Wehr and Lohr, 1999). Global Positioning System (GPS) receivers in the aircraft and on the ground provide platform positioning. The GPS receivers record pseudo-range and phase information for post-processing. Platform orientation information comes from an Inertial Measurement Unit (IMU) containing three orthogonal accelerometers and gyroscopes. An aided-Inertial Navigation System (INS) solution for the aircraft's attitude is estimated from the IMU output and the GPS information. Wehr, A. and U. Lohr, 1999, Airborne laser scanning - an introduction and overview, ISPRS Journal of Photogrammetry and Remote Sensing, vol. 54, no.2-3, pp.68-82.
Purpose: The data described in this document will be compared with previous and forthcoming data sets to determine rates of shoreline change along the Southern California coastline. The SCBPS program is designed to improve the understanding of beach sand transport by waves and currents, thus improving local and regional coastal management.
Use Limitations
  • These data depict the elevations at the time of the survey and are only accurate for that time. Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations. Any conclusions drawn from analysis of this information are not the responsibility of NOAA or any of its partners. These data are NOT to be used for navigational purposes.
  • While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.
  • Southern California Beach Processes Study (SCBPS)/Coastal Data Information Program (CDIP) part of Scripps Institution of Oceanography (SIO) in cooperation with Bureau of Economic Geology, University of Texas at Austin.
  • DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
  • Scripps Institute of Oceanography
  • Center for Space Research, University of Texas at Austin
  • Bureau of Economic Geology, University of Texas at Austin
  • DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
Time Period: 2006-03-24 to 2006-03-25
Spatial Reference System: urn:ogc:def:crs:EPSG::4269
Spatial Bounding Box Coordinates:
N: 33.768792
S: 32.510392
E: -117.116806
W: -118.203606
Spatial Coverage Map:
Theme keywords none
  • shoreline
  • beach
  • Bathymetry/Topography
  • lidar
  • laser
  • point file
  • Latitude
  • Longitude
  • intensity
Place keywords none
  • US
  • California
  • San Diego
  • Pacific Ocean
Use Constraints No constraint information available
Fees Fee information not available.
Lineage information for: dataset
  • Bureau of Economic Geology, University of Texas at Austin
  • DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
Processing Steps
  • 2006-07-26T00:00:00 - GPS and XYZ-Point Data Processing Transfer raw ALTM 1225 flight data (laser ranges with associated scan angle information and IMU data), airborne GPS data collected at 1 Hz using Ashtech receiver, and ground-based GPS data collected at 1 Hz using Ashtech Z-12 receivers to processing computer. Generate decimated lidar point file from above three data sets using Optech's Realm 2.27 software. This is a 9-column ASCII data set with the following format: time tag; first pulse Easting, Northing, HAE; last pulse Easting, Northing, HAE; first pulse intensity; and last pulse intensity. View decimated lidar point file to check data coverage (i.e. sufficient overlap of flight lines and point spacing). Compute base station coordinates using National Geodetic Survey's PAGES-NT software. Compute aircraft trajectories from each base station GPS dataset using National Geodetic Survey's KINPOS software. Solutions for base stations coordinates and aircraft trajectories are in the International Terrestrial Reference Frame of 2000 (ITRF2000). A final aircraft trajectory was computed from a weighted average of the trajectories from the two base stations. Epoch-by-epoch weighting for the individual trajectories was inversely proportional to the baseline length (distance from base station) and solution RMS. Transformed trajectory solution from ITRF2000 to North American Datum of 1983 (NAD83) using the National Geodetic Survey's Horizontal Time Dependent Positioning software ( Input NAD83 trajectories and aircraft inertial measurement unit data into Applanix's POSProc version 2.1.4 to compute an optimal 50Hz inertial navigation solution (INS) and smoothed best estimate of trajectory (SBET). Substitute the INS and SBET into Realm 2.27. Generate a set of initial lidar instrument calibration parameters (pitch, roll, scale, and elevation bias) for each lidar flight, then incrementally improve parameters by iteratively comparing a subset of the lidar output to the GPS kinematic ground control. Once the instrument calibration parameters are sufficiently accurate, create the complete lidar point file (9-column ASCII file) for the entire survey area in UTM Zone 11 with elevations being heights above the GRS-80 reference ellipsoid (HAE). The output format from REALM 2.27 was a 9-column ASCII file containing: the second in the GPS week, easting, northing and HAE of the first lidar return, the easting, northing and HAE of the last lidar return, and the laser backscatter intensity of the first and last returns. Using the GEOID99 geoid model, heights above the GRS80 ellipsoid were converted to orthometric heights with respect to the North American Vertical Datum of 1988 (NAVD88). Parse the 9-column lidar point file into 3.75-minute quarter-quadrangle components. Convert UTM Easting and Northing to geodetic latitude and longitude with respect to the GRS80 ellipsoid. The conversion was computed using the TMGEOD and TCONPC fortran subroutines written by T. Vincenty (NGS). Each record contains 9 columns of data: time tag (seconds in the GPS week), first return Latitude,first return Longitude, first return NAVD88, last return Latitude, last return Longitude, last return NAVD88, first return intensity, and last return intensity. In some cases either the first or last return values may be missing (5 columns). Latitude and longitude are in decimal degrees with nine significant digits to retain the 0.01m resolution of the UTM coordinates. West longitude is negative and north latitude is positive. The UTM quarter-quad files were re-organized into latitude delineated files. UTM quarter-quads files that were delineated by the same upper and lower latitude bounds were concatenated. The lat-long files were named by the month-year of the survey (e.g. mar06) and the lower latitude bounding the quarter-quad.
  • 2007-07-24T00:00:00 - The NOAA Coastal Services Center (CSC) received files in ASCII format. The files contained LiDAR intensity and elevation measurements. CSC performed the following processing on the data to make it available within the LiDAR Data Retrieval Tool (LDART) 1. Data returned to ellipsoid heights from NAVD88, using GEOID99. 2. Data converted to LAS format. 3. The LAS data were sorted by latitude and the headers were updated.
  • 2007-12-26T00:00:00 - The NOAA National Geophysical Data Center (NGDC) received lidar data files via ftp transfer from the NOAA Coastal Services Center. The data are currently being served via NOAA CSC Digital Coast at The data can be used to re-populate the system. The data are archived in LAS or LAZ format. The LAS format is an industry standard for LiDAR data developed by the American Society of Photogrammetry and Remote Sensing (ASPRS); LAZ is a loseless compressed version of LAS developed by Martin Isenburg ( The data are exclusively in geographic coordinates (either NAD83 or ITRF94). The data are referenced vertically to the ellipsoid (either GRS80 or ITRF94), allowing for the ability to apply the most up to date geoid model when transforming to orthometric heights.
Source Datasets
  • Raw lidar data output from ALTM 1225, SN#99D118
    • Description of Source: Source Contribution: Raw lidar files. Raw lidar data from ALTM 1225 (all times UTC) 08306 Pass A (Carlsbad to Mexico) = 18:41-19:14 Pass B (Mexico to Point Loma) = 19:17-19:24 Pass C (Point Loma to Mexico) = 19:29-19:35 Pass D (Point Loma to Dana Point) = 20:06-20:43 Pass E (Dana Point to La Jolla) = 20:49-21:16 Pass F (La Jolla to Dana Point) = 21:39-22:26 Pass G (Dana Point to Carlsbad) = 22:13-22:26 2 Calibration Passes = 21:19-21:25 08406 Pass H (Newport Beach to Long Beach) = 20:44-20:56 Pass I (Long Beach to Dana Point) = 21:00-21:17 Pass J (Dana Point to Long Beach) = 21:31-21:47 Pass K (Long Beach to Dana Point) = 21:51-22:08 Pass L (Dana Point to Newport Beach) = 22:12-22:19 2 Calibration Passes = 22:24-22:30 Source Type: digital file
    • Temporal extent used: 2006-03-24 to 2006-03-25
  • Air and Ground GPS files from 08306 and 08406
    • Description of Source: Source Contribution: GPS data. air and ground GPS files base station coordinates Easting, Northing, HAE in NAD83, Zone 11 (Latitude, Longitude): Seal Beach (SEAL) = 399190.210, 3733584.054, -27.287 (N 33 44 15.03814, W 118 05 17.77225) San Onofre (SANO) = 447430.058, 3693036.854, -5.193 (N 33 22 31.08745, W 117 33 54.55130) Point Loma (LOMA) = 477399.573, 3614791.280, 90.855 (N 32 40 13.99848, W 117 14 27.74927) Source Type: digital file
    • Temporal extent used: 2006-03-24 to 2006-03-25
Last Modified: 2013-06-11
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