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May 2002 Lidar Point Data of Southern California Coastline: Dana Point to Point La Jolla

This data set contains lidar point data from a strip of Southern California coastline (including water, beach, cliffs, and top of cliffs) from Dana Point to Point La Jolla. 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 is installed in a single engine Cessna 206 (tail number N4589U) owned and operated by the Texas State Aircraft Pooling Board. The lidar data set described by this document was collected at low tide on 22 May 2002 (14202) between 18:20 and 21:39 UTC (actual data collection). Conditions on that day were light clouds along the shoreline as well as offshore. 99d118 instrument settings for this flight were; laser pulse rate: 25kHz, scanner rate: 26Hz (28Hz for calibration target), scan angle: +/-20deg, beam divergence: narrow, altitude: 680-780m AGL for first half of flight and 900-950 for second half of flight, and ground speed: 83-125kts. Two GPS base stations (Scripps pier and San Onofre Power Plant) were operating during the survey. The survey included 3 shoreline passes between Dana Point and Point La Jolla as well as one offshore pass along the 20m isobath. 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: 2003-04-17
Data Presentation Form: Digital image
Dataset Progress Status Complete
Data Update Frequency: As needed
Supplemental Information:
The ALTM 1225 has the following specifications: operating altitude = 410-2,000 m AGL; 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 = 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: Unknown to Unknown
Spatial Reference System: urn:ogc:def:crs:EPSG::4269
Spatial Bounding Box Coordinates:
N: 33.471978
S: 32.838178
E: -117.249643
W: -117.704143
Spatial Coverage Map:
Theme keywords none
  • Bathymetry/Topography
  • shoreline
  • beach
  • 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, The 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
  • 2003-04-16T00:00:00 - Transfer raw ALTM 1225 flight data, airborne GPS data collected at 1 Hz using Ashtech receiver, and ground-based GPS data collected at 1 Hz using Ashtech and Trimble 4000SSI receivers to NT workstation. 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 software. Computed aircraft trajectories for both base stations using National Geodetic Survey's KINPOS software. Coordinates for base stations and trajectories are in the International Terrestrial Reference Frame of 2000 (ITRF2000) datum. Trajectories from both base stations were merged into one. Weighting for trajectory merge is based upon baseline length (distance from base station) and solution RMS. Transformed trajectory solution from ITRF2000 to North American Datum of 1983 (NAD83). Use NAD83 trajectories and aircraft inertial measurement unit data in Applanix's POSProc version 2.1.4 to compute an optimal 50Hz inertial navigation solution. Substitute the aircraft position and attitude information from the inertial navigation solution into Realm 2.27. Extract calibration area data set from lidar point file for quality control and instrument calibration checks. If necessary, use multiple iterations to adjust calibration parameters (pitch, roll, and scale) and reprocess sample data set. Then generate entire lidar point file (9-column ASCII file). Use the Geiod99 geoid model to convert from Height Above the GRS80 ellipsoid to elevations with respect to the North American Vertical Datum 88 (NAVD88). Transfer point file from NT workstation to UNIX workstation. Parse the 9-column lidar point file into 3.75-minute quarter-quadrangle components and apply elevation bias correction (determined during calibration step). There are some points in the file that only contain 5-columns. These are points that either the first or last pulse was not recorded. UTM Easting and Northing were converted 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). Latitude and longitude are in decimal degrees with nine significant digits to retain the 0.01m resolution of the UTM coordinates. 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). West longitude is negative and north latitude is positive. The eighteen UTM quarter-quad files were re-organized into ten 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. may02) and the lower latitude bounding the quarter-quad. The quarter-quad file name and the corresponding lat-long file name are shown below. d_point_nw.asc,d_point_ne.asc = may02_33.4375.asc d_point_se.asc, s_clem_sw.asc = may02_33.3750.asc s_ono_nw.asc, s_ono_ne.asc, l_pul_nw.asc = may02_33.3125.asc l_pul_sw.asc, l_pul_se.asc = may02_33.2500.asc oside_ne.asc = may02_33.1875.asc oside_se.asc, s_luis_sw.asc = may02_33.1250.asc encin_nw.asc, encin_ne.asc = may02_33.0625.asc encin_se.asc = may02_33.0000.asc d_mar_oew_ne.asc = may02_32.9375.asc d_mar_oew_se.asc = may02_32.8750.asc l_jol_oew_ne.asc = may02_32.8125.asc
  • 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
    • Description of Source: Source Contribution: Raw lidar data files. Raw lidar data from ALTM 1225 (all times are UTC) 20m isobath = 18:27-18:51 Pass 1 (Dana Point to Point La Jolla) = 19:14-19:41 Pass 2 (Point La Jolla to Dana Point) = 19:48-20:20 Pass 3 (Dana Point to Point Mateo) = 20:23-20:30 Pass 4 (Dana Point to Point Mateo) = 20:54-20:58 Pass 5 (Point Mateo to Dana Point) = 21:02-21:07 Pass 6 (Dana Point to Point La Jolla) = 21:11-21:39 6 calibration passes between 19:00-19:04 and 20:33-20:45 Source Type: digital file
    • Temporal extent used: Unknown to
  • Air and Ground GPS files from 14202
    • Description of Source: Source Contribution: GPS data. Air and ground GPS files base station coordinates (Easting, Northing, HAE) in NAD83: Scripps Pier (PIER) = 476093.032, 3636524.941, -25.424 San Onofre (GPS1) = 447430.150, 3693036.731, -5.166 Source Type: digital file
    • Temporal extent used: Unknown to
Last Modified: 2013-05-07
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