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September 2008 Scripps Institute of Oceanography (SIO) Lidar of the Southern California Coastline: Long Beach to US/Mexico Border

browse graphicThis kmz file shows the extent of coverage for the September 2008 SIO Southern California Coastline lidar data set.
This lidar point data set was collected during low tide conditions along an approximately 500-700 meter wide strip of the Southern California coastline within an area extending south from Long Beach to the US/Mexico border. Data were collected in Los Angeles, Orange and San Diego counties from south of the Downtown Long Beach Marina in Long Beach, California to Leucadia, California on September 30, 2008 between 20:46 and 23:25 UTC. Data were collected in Orange and San Diego counties from Dana Point, California to south of the United States-Mexico border near Playas de Tijuana, Baja California, Mexico on September 29, 2008 between 20:08 and 23:08 UTC. Data set features include water, beach, cliffs, and top of cliffs. The all points data set contains the complete point cloud of first and last return elevation and laser intensity measurements recorded during the fall 2008 airborne lidar survey conducted semi-annually by the University of Texas at Austin for the Southern California Beach Processes Study. The data set was generated by the processing of laser range, scan angle, and aircraft attitude data collected using an Optech Inc. Airborne Laser Terrain Mapper (ALTM) 1225 system and geodetic quality Global Positioning System (GPS) airborne and ground-based receivers. Instrument settings and parameters during survey were: Nominal on-ground beam diameter: 25 cm Pulse rate: 25 kHz Maximum number of returns recorded: 2 Minimum separation between detected returns from a single pulse: 4.3 m Laser wavelength: 1064 nm Frequency of GPS sampling: 1 Hz Frequency of IMU sampling: 50 Hz; Scan angle: +/- 20 degrees Nominal height of instrument above ground: 1100 m Nominal single-swath pulse density: 2 m Nominal aggregate pulse density: 0.75 Nature of vertical control: Kinematic and static GPS points

Cite this dataset when used as a source.

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    Distribution Formats
    • LAZ
    Distributor Distributor information not available
    Point of Contact Roberto Gutierrez
    University of Texas at Austin Center for Space Research
    Documentation links not available.
    • Southern California Beach Processes Study (SCBPS)/Coastal Data Information Program (CDIP) part of Scripps Institution of Oceanography (SIO) in cooperation with the Center for Space Research and the Bureau of Economic Geology, University of Texas at Austin
    • Scripps Institute of Oceanography
    • Center for Space Research, University of Texas at Austin
    • Bureau of Economic Geology, University of Texas at Austin
      • publication: 2011-03-01
      Data Presentation Form: Digital image
      Dataset Progress Status Complete
      Data Update Frequency: As needed
      Supplemental Information: The University of Texas at Austin Center for Space Research operated an Optech Inc. Airborne Laser Terrain Mapper (ALTM) 1225 system installed in a single engine Cessna 206 to collect lidar data for the survey. Global Positioning System (GPS) data were collected simultaneously with three geodetic quality Ashtech Z-12 receivers installed in the aircraft and at two temporary base stations operated during the survey. An Inertial Measurement Unit (IMU) used three orthogonal accelerometers and gyroscopes to collect in-flight instrument orientation information. The Cessna 206 aircraft used in the survey is owned and operated by the Texas Department of Transportation. 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 records the range and backscatter intensity of the first and last laser reflection using an Avalanche Photo diode 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.
      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.
      Time Period: 2008-09-29  to  2008-09-30
      Spatial Reference System:
      Spatial Bounding Box Coordinates:
      N: 33.662182
      S: 32.509061
      E: -117.117638
      W: -118.000250
      Spatial Coverage Map:
      • Bathymetry/Topography
      • Lidar
      • GPS
      • GPS Receivers
      • Beaches
      • Coastal Landforms/Processes
      • Landforms
      • Terrain Elevation
      • Coastal Elevation
      • Shorelines
      • United States
      • California
      • Los Angeles County
      • Orange County
      • San Diego County
      • Surfside Beach
      • Huntington City Beach
      • Newport Beach
      • Little Corona Del Mar Beach
      • Balboa Beach
      • Main Beach
      • Arch Beach
      • Victoria Beach
      • Aliso Beach
      • Coast Royale Beach
      • Poche Beach
      • San Clemente City Beach
      • Trestles Beach
      • San Onofre Beach
      • Harbor Beach
      • Oceanside City Beach
      • South Oceanside Beach
      • Saint Malo Beach
      • South Carlsbad State Beach
      • Torrey Pines State Beach
      • Blacks Beach
      • Torrey Pines City Beach
      • La Jolla Shores Beach
      • Boomer Beach
      • Childrens Pool Beach
      • Wipeout Beach
      • Marine Street Beach
      • Windansea Beach
      • Dog Beach
      • Ocean Beach City Beach
      • North Beach
      • Coronado City Beach
      • Central Beach
      • Coronado Shores Beach
      Use Constraints No constraint information available
      Fees Fee information not available.
      Source Datasets
      • ALTM 1225 range files
        • Description of Source: Source Contribution: Raw lidar range files. Range files are the source data collected by the ALTM 1225 sensor. ALTM 1225 range files used for this survey are grouped by date, day of year, pass, pass location, and time of collection (all times UTC): Fall 2008 September 29, 2008 (Day of Year = 273), HH:MM in UTC; 27308 Pass A (San Onofre to La Jolla) 20:07-20:28 27308 Pass B (La Jolla to Dana Point) 20:31-21:01 27308 Pass C (La Jolla to Point Loma) 21:31-21:40 27308 Pass D (Coronado (North Island NAS) to Playas de Tijuana) 21:45-21:52 27308 Pass E (Playas de Tijuana to Coronado (North Island NAS)) 21:55-22:04 27308 Pass F (Coronado (North Island NAS) to Playas de Tijuana) 22:09-22:16 27308 Pass G (Point Loma to Santa Margarita River) 22:23-23:08 September 30, 2008 (Day of Year = 274), HH:MM in UTC; 27408 Pass A (Leucadia to Long Beach) 20:46-21:25 27408 Pass B (Long Beach to Dana Point) 21:29-21:48 27408 Pass C (Dana Point to Long Beach) 21:52-22:10 27408 Pass D (Long Beach to Carlsbad) 22:16-23:02 27408 Pass E (Leucadia to Dana Point) 23:06-23:24 Source Type: digital files
        • Temporal extent used:  2008-09-29  to  2008-09-30
      • Air and Ground GPS L1, L2, pseudorange and phase files from September 29 & 30, 2008 (Days of Year 273 & 274)
        • Description of Source: Source Contribution: GPS data. Two Ashtech Z-12 GPS receivers placed at precisely located base stations collected GPS data at 1 second intervals throughout the period of airborne lidar data collection. Data collection commenced prior to take off and ceased subsequent to touch down. A third Ashtech Z-12 GPS receiver collected in-flight GPS data at 1 second intervals. Data were downloaded and stored each day after flight completion. File names included standardized references to location and date. These data were used for ALTM range file processing. See process steps for more detailed information. GPS base station locations by survey day: September 30 (day 274), 2008: SANO, SEAL September 29 (day 274), 2008: SANO, LOMA GPS base station attributes: ID: SANO Name: HPGN-CA SDGPS01, 1990; Description: San Diego County Engineer Department GPS control point at San Onofre NAD83 Coordinates and HAE: 33d 22m 31.08420s N, 117d 33m 54.54673s W, -5.17 ID: SEAL Name: HPGN CA 12 01; Description: California High Precision GPS Network 12 01 (PID:DY9309) NAD83 Coordinates and HAE: 33d 44m 15.03481s N, 118d 05m 17.76708s W, -27.228 ID: LOMA Name: LOMA EAST; Description: NGS Control Point at Loma Point, LOMA EAST, 1994 (PID: AC6092) NAD83 Coordinates and HAE: 32d 40m 13.99579s N, 117d 14m 27.74509s W, 90.892 Source Type: digital files
        • Temporal extent used:  2008-09-29  to  2008-09-30
      • GPS Continuously Operating Reference Station (CORS) at Pinyon Flats, CA
        • Description of Source: Source Contribution: CORS base station data (StationID: PIN1). GPS base stations solutions were estimated with respect to the GPS Continuously Operating Reference Station (CORS) at Pinyon Flats, CA. DESIGNATION: PINON 1 PGGA CORS ARP CORS_ID: PIN1 NGS PID: AF9708 Source Type: online
        • Temporal extent used:  2008-09-29  to  2008-09-30
      Lineage Statement Lineage statement not available.
      • Center for Space Research, University of Texas at Austin
      • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
      Processing Steps
      • ALTM range files were downloaded from the Optech ALTM 1225 system and decoded using Optech's REALM 3.0 tape decode program.
      • Raw GPS data were downloaded from three Ashtech Z-12 GPS receivers. One receiver collected in-flight aircraft data; the other two collected data during flight time at separate base stations. The GPS data were converted into RINEX2 format with pseudorange smoothing applied. The National Geodetic Survey's PAGES-NT software was used to compute double differenced, ionospherically corrected, static GPS solutions for each GPS base station with precise ephemerides from the International GPS Service (IGS) with respect to selected CORS sites. As part of the solution tropospheric zenith delays were estimated and L1 and L2 phase biases were fixed as integers. Aircraft trajectories were estimated with respect to all base stations using National Geodetic Survey's Kinematic and Rapid-Static Software (KARS) software. Trajectories were double-differenced, ionospherically corrected, bias-fixed GPS solutions computed with precise IGS ephemerides. Coordinates for base stations and trajectories were in the International Terrestrial Reference Frame of 2000 (ITRF00). Aircraft trajectories were transformed from the ITRF00 to North American Datum of 1983 (NAD83) using the Horizontal Time Dependent Positioning (HDTP) software (Snay, 1999).
      • The 1 Hz GPS trajectory and 50Hz aircraft inertial measurement unit (IMU) data were combined in Applanix's POSProc version 4.2 to compute an aided inertial navigation solution (INS) and a 50 Hz, smoothed best estimate of trajectory (SBET). The POSPac software employs a Kalman filter to obtain a blended navigation solution. Afterwards, smoothing was applied to the solution to obtain the SBET for the aircraft.
      • The SBET, laser range observations, scanner position information, and GPS/internal clock files were processed in the Realm 2.27 software suite to generate uncalibrated lidar data points in the Universal Transverse Mercator (UTM) projection. Lidar point data were compared to 1998 ATM LIDAR data over several cross-track piers and roads to estimate lidar instrument calibration parameters: roll and pitch biases, scanner scale factor, and first/last return elevation biases. An iterative, least-squares methodology was used to estimate calibration parameters so as to minimize differences between lidar and ground GPS data. Samples of lidar data were used to create high-resolution digital elevation models (DEM); these DEMs were inspected for horizontal or vertical anomalies. Data collected on September 30, 2008, were compared to kinematic GPS points collected along the E. Pacific Coast Hwy near Laguna Beach. Data collected on September 29, 2008, were compared to kinematic GPS points collected in a parking lot near North Torrey Pines Road. After system calibration and initial quality control step, the adjusted lidar x,y,z-point data were generated by REALM software and output using the UTM Zone 11 coordinate system with elevations being heights above the GRS-80 reference ellipsoid (HAE). The output format from REALM 2.27 is a headerless space-delimited 9-column ASCII file that contains: Column 1 = the point time tag in seconds in the GPS week; Columns 2-4 = the UTM Zone 11 North easting, UTM Zone 11 North northing and height above ellipsoid (HAE) of the first lidar return; Columns 5-7 = the UTM Zone 11 North easting, UTM Zone 11 North northing and HAE of the last lidar return; and Columns 8 & 9 = the laser backscatter intensity of the first and last returns.
      • Heights above the GRS80 ellipsoid (HAE) were converted to orthometric heights with respect to the North American Vertical Datum of 1988 (NAVD88), using the GEOID99 model. GPS time tags were used to separate the data collected on a single day into distinct passes. The resulting pass data sets were then parsed into 3.75-minute USGS quarter-quadrangle components containing the complete point cloud. Each output file includes data points found within a 20 meter buffer area surrounding each quarter quadrangle. Outlier data points that exceeded designated elevation thresholds (< -20 m or > 250 m) were eliminated during the parsing process.
      • The NOAA Coastal Services Center (CSC) received the lidar files in ASCII format. The files contained lidar intensity and elevation measurements. CSC performed the following processing for data storage and Digital Coast provisioning purposes: 1. Data converted from UTM coordinates to geographic coordinates. 2. Data converted from NAVD88 heights to ellipsoid heights using GEOID99. 3. Data converted from dual return xyz format to xyz text format with return numbers to las format. 4. The LAS data were sorted by latitude and the headers were updated.
      • 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.

      Metadata Last Modified: 2013-06-05

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