September 2004 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 N6602L) owned and operated by Aspen Helicopter, Inc. The lidar data set described by this document was collected on 28-30 September 2004; Julian Days 27204, 27304, and 27404 (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: 950-1150m AGL, and ground speed: 90-132kts. Settings were different on final day of surveying due to low clouds and flight restrictions: beam divergence: wide, altitude: 320-620m AGL, and ground speed: 101-121kts. Three GPS base stations (Seal Beach, Dana Point, and Point Loma, see Lineage, Source_Information, Source_Contribution for coordinates) were operating during the survey. 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.
|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
SCBPS/CDIP, Scripps Institution of Oceanography
Documentation links not available.
|Data Presentation Form:||
|Dataset Progress Status||Complete|
|Data Update Frequency:||As needed|
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.|
|Time Period:||2004-09-28 to 2004-09-30|
|Spatial Reference System:||urn:ogc:def:crs:EPSG::4269 Ellipsoid in Meters|
|Spatial Bounding Box Coordinates:||
|Spatial Coverage Map:|
|Use Constraints||No constraint information available|
|Fees||Fee information not available.|
Last Modified: 2013-05-07
For questions about the information on this page, please email: firstname.lastname@example.org