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2010 U.S. Geological Survey (USGS) Topographic Lidar: Channel Islands, California

browse graphicThis kmz file shows the extent of coverage for the 2010 USGS Channel Islands lidar data set.
Terrapoint collected LiDAR for 197 square miles covering five islands off the coast of Los Angeles, California. These islands are part of the Channel Islands National Park and consists of San Miguel Island, Santa Rosa Island, Santa Cruz Island, Anacapa Island, and Santa Barbara Island. The nominal pulse spacing for this project was better than 0.7 meters. This project was collected with a sensor which collects waveform data and provides an intensity value for each discrete pulse extracted from the waveform. GPS Week Time, Intensity, Flightline and echo number attributes were provided for each LiDAR point. Dewberry used proprietary procedures to classify the LAS according to USGS ARRA specifications: 1-Unclassified 2-Ground 7-Noise 9-Water 10-Ignored Ground due to breakline proximity. Dewberry produced 3D breaklines, seamless DSMs, and seamless hydro flattened DEMs for the 204 tiles (2000 m x 2000 m) that cover the project area. Area mapped by island is as follows: Santa Barbara Island-1 sq. mi. Anacapa Island-1 sq. mi. San Miguel Island-15 sq. mi. Santa Rosa Island-83 sq. mi. Santa Cruz Island-97 sq. mi. Two UTM zones cover the Channel Islands. The islands delivered per each UTM zone are as follows (please note that Santa Rosa Island was delivered in both UTM zone 10 and UTM zone 11): UTM Zone 10: Santa Rosa Island San Miguel Island UTM Zone 11: Santa Barbara Island Santa Rosa Island Santa Cruz Island Anacapa Island The NOAA Coastal Services Center received the data in UTM Zones 10 and 11. The data were converted to geographic coordinates and from NAVD88 heights to ellipsoid heights using GEOID09. These files were converted for data storage and Digital Coast provisioning purposes.

Cite this dataset when used as a source.

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    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
    Point of Contact USGS
    (573) 308-3612
    ckelly@usgs.gov
    Documentation links not available.
    Originator
    • DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Originator
    • U.S. Geological Survey
    Publisher
    • DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Date(s)
    • publication: 2012-10-01
    Data Presentation Form: Digital image
    Dataset Progress Status Complete
    Data Update Frequency: As needed
    Purpose: The purpose of this LiDAR data was to produce high accuracy 3D elevation products, including tiled LiDAR in LAS 1.2 format, 3D breaklines, 1 m cell size hydro flattened Digital Elevation Models (DEMs), and 1 m cell size Digital Surface Models (DSMs).
    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.
    Time Period: 2010-03-11  to  2010-04-08
    Spatial Reference System: urn:ogc:def:crs:EPSG::4269 Ellipsoid in Meters
    Spatial Bounding Box Coordinates:
    N: 34.087167
    S: 33.449425
    E: -119.013085
    W: -120.479098
    Spatial Coverage Map:
    Themes
    • Topography/Bathymetry
    • DTM
    • Elevation
    • Lidar
    • LAS
    • DEM
    • Hydro Flattened
    • Breaklines
    • DSM
    • Digital Surface Model
    Places
    • United States
    • California
    • Channel Islands National Park
    • Anacapa Island
    • Santa Barbara Island
    • San Miguel Island
    • Santa Rosa Island
    • Santa Cruz Island
    • Offshore Los Angeles, California
    Use Constraints No constraint information available
    Fees Fee information not available.
    Lineage Statement Lineage statement not available.
    Processor
    • Terrapoint USA
    • Dewberry - Geospatial Services Group
    • 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
    • Terrapoint used their latest helicopter-based LiDAR sensor. The Riegl LMS-Q560 helicopter-mounted system is designed specifically for small block sites and corridor applications. A combination of Sokkia GSR 2600 and NovAtel DL-4+ dual-frequency GPS receivers were used to support the airborne operations of this survey and to establish the GPS control network. Airborne GPS kinematic data was processed on-site using GrafNav kinematic On-The-Fly (OTF) software. Flights were flown with a minimum of 6 satellites in view (13o above the horizon) and with a PDOP of better than 4. Distances from base station to aircraft were kept to a maximum of 24 km. For all flights, the GPS data can be classified as excellent, with GPS residuals of 3cm average or better but no larger than 10cm being recorded. The initial step of calibration is to verify availability and status of all needed GPS and Laser data against field notes and compile any data if not complete. Laser data points are generated using Terrapoint's proprietary laser post-processing software. This software combines the raw laser range and angle data file with the finalized GPS/IMU information. The resulting point cloud has been projected into the desired coordinate system in LAS binary format. All missions are validated against the adjoining missions for relative vertical biases and collected GPS kinematic ground truthing points for absolute vertical accuracy purposes. On a project level, a coverage check is carried out to ensure no slivers are present in areas where it was possible to acquire LiDAR at a safe AGL.
    • Dewberry utilizes a variety of software suites for inventory management, classification, and data processing. All LiDAR related processes begin by importing the data into the GeoCue task management software. GeoCue allows the data to retain its delivered tiling scheme (2000 m by 2000 m). The tiled data is then opened in Terrascan where Dewberry uses proprietary ground classification routines to remove any non-ground points and generate an accurate ground surface. The ground routine consists of three main parameters (building size, iteration angle, and iteration distance); by adjusting these parameters and running several iterations of this routine an initial ground surface is developed. The building size parameter sets a roaming window size. Each tile is loaded with neighboring points from adjacent tiles and the routine classifies the data section by section based on this roaming window size. The second most important parameter is the maximum terrain angle, which sets the highest allowed terrain angle within the model. Once the ground routine has been completed a manual quality control routine is done using hillshades, cross-sections, and profiles within the Terrasolid software suite. After this QC step, a peer review and supervisor manual inspection is completed on a percentage of the classified tiles based on the project size and variability of the terrain. After the ground classification corrections were completed, the dataset was processed through a water classification routine that utilizes breaklines compiled by Dewberry to automatically classify hydrographic features. The water classification routine selects ground points within the breakline polygons and automatically classifies them as class 9, water. During this water classification routine, points which are in close proximity (2 ft) to the hydrographic features are moved to class 10, an ignored ground. In addition to classes 1, 2, 9, and 10, St. Johns allows for a Class 7, noise points. This class was only used if needed when points could manually be identified as low/high points. The fully classified dataset is then processed through Dewberry's comprehensive quality control program. The data were classified as follows: Class 1 = Unclassified. This class includes vegetation, buildings, noise etc. Class 2 = Ground Class 7 = Noise Class 9 = Water Class 10= Ignored Ground The LAS header information was verified to contain the following: Class (Integer) GPS Week Time (0.0001 seconds) Easting (0.01 foot) Northing (0.01 foot) Elevation (0.01 foot) Echo Number (Integer 1 to 4) Echo (Integer 1 to 4) Intensity (8 bit integer) Flight Line (Integer) Lidar Scan Angle (Integer degree)
    • The NOAA Coastal Services Center (CSC) received topographic files in LAS format. The files contained lidar elevation and intensity measurements. The data were received in UTM Zones 10 and 11 (NAD83) coordinates and were vertically referenced to NAVD88 using the Geoid09 model. The vertical units of the data were meters. CSC performed the following processing for data storage and Digital Coast provisioning purposes: 1. The topographic las files were converted from orthometric (NAVD88) heights to ellipsoidal heights using Geoid09. 2. The data were converted to LAZ format.
    • 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 http://www.csc.noaa.gov/digitalcoast/. 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 (http://www.laszip.org/). 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: 2013-01-22

    For questions about the information on this page, please email: mike.sutherland@noaa.gov