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2009 Puget Sound Lidar Consortium (PSLC) Topographic LiDAR: Nooksack River

browse graphicThis kmz file shows the extent of coverage for the 2009 PSLC Nooksack River, WA lidar data set.
Watershed Sciences, Inc. (WS) collected Light Detection and Ranging (LiDAR) data of the Nooksack River in Washington on February 20th - 22nd, 2009. The total area of delivered LiDAR is 35,662 acres. The requested area was expanded to include a 100 m buffer to ensure complete coverage and adequate point densities around survey area boundaries.

Cite this dataset when used as a source.

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    Distribution Formats
    • LAZ
    Distributor DOC/NOAA/NOS/CSC > Coastal Services Center, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Point of Contact Diana Martinez
    Puget Sound Lidar Consortium (PSLC)
    206-971-3052
    dmartinez@psrc.org
    Associated Resources
    • Lidar Dataset Supplemental Information
    Originator
    • DOC/NOAA/NOS/CSC > Coastal Services Center, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Originator
    • Diana Martinez
      Puget Sound Lidar Consortium (PSLC)
    Publisher
    • DOC/NOAA/NOS/CSC > Coastal Services Center, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Date(s)
    • publication: 2013-12-05
    Data Presentation Form: Digital image
    Dataset Progress Status Complete
    Data Update Frequency: As needed
    Purpose: Provide high resolution terrain elevation and land cover elevation data.
    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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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: 2009-02-20T1200  to  2009-02-22T1200
    Spatial Reference System: urn:ogc:def:crs:EPSG::4269 Ellipsoid in Meters
    Spatial Bounding Box Coordinates:
    N: 48.92931299
    S: 48.66437468
    E: -122.12790865
    W: -122.38339818
    Spatial Coverage Map:
    Themes
    • Topography
    • Elevation
    • Model
    • LiDAR
    • LAZ
    • LAS
    • Remote Sensing
    Places
    • US
    • Washington
    • Whatcom County
    Use Constraints No constraint information available
    Fees Fee information not available.
    Lineage Statement Lineage statement not available.
    Processor
    • DOC/NOAA/NOS/CSC > Coastal Services Center, 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
    • Acquisition. The lidar survey uses a Leica ALS50 Phase II laser system. For the Wenatchee USGS survey area, the sensor scan angle +/- 14 degrees from nadir with a pulse rate designed to yield an average native density (number of pulses emitted by the laser system) of more than 8 points per square meter over terrestrial surfaces. All survey areas were surveyed with an opposing flight line side-lap of more than 50% (less than 100% overlap) to reduce laser shadowing and increase surface laser painting. The Leica ALS50 Phase II system allows up to four range measurements (returns) per pulse, and all discernible laser returns were processed for the output dataset. It is not uncommon for some types of surfaces (e.g. dense vegetation or water) to return fewer pulses than the laser originally emitted. These discrepancies between 'native' and 'delivered' density will vary depending on terrain, land cover and the prevalence of water bodies. To accurately solve for laser points position (geographic coordinates x, y, z) the positional coordinates of the airborne sensor and the attitude of the aircraft were recorded continuously throughout the lidar data collection mission. Aircraft position was measured twice per second (2 Hz) by an onboard differential GPS unit. Aircraft attitude was measured 200 times per second (200 Hz) as pitch, roll, yaw (heading) from an onboard inertial measurement unit(IMU). To allow for post-processing correction and calibration, aircraft/sensor position and attitude data are indexed by GPS time.
    • Resolved kinematic corrections for aircraft position data using kinematic aircraft GPS and static ground GPS data. Software - Waypoint GPS v.8.10, Trimble Geomatics Office v.1.62 Developed a smoothed best estimate of trajectory (SBET) file that blends post-processed aircraft position with attitude data Sensor head position and attitude were calculated throughout the survey. The SBET data were used extensively for laser point processing. Software - IPAS v.1.4 Calculated laser point position by associating SBET position to each laser point return time, scan angle, intensity, etc. Created raw laser point cloud data for the entire survey in *.las(ASPRS v1.1) format. Software: ALS Post Processing Software v.2.69 Imported raw laser points into manageable blocks (less than 500 MB) to perform manual relative accuracy calibration and filter for pits/birds. Ground points were then classified for individual flight lines (to be used for relative accuracy testing and calibration). Software - TerraScan v.9.001 Using ground classified points per each flight line, the relative accuracy was tested. Automated line-to-line calibrations were then performed for system attitude parameters (pitch, roll, heading), mirror flex (scale) and GPS/IMU drift. Calibrations were performed on ground classified points from paired flight lines. Every flight line was used for relative accuracy calibration. Software - TerraMatch v.9.001 Position and attitude data were imported. Resulting data were classified as ground and nonground points. Statistical absolute accuracy was assessed via direct comparisons of ground classified points to ground RTK survey data. Data were then converted to orthometric elevations (NAVD88) by applying a Geoid03 correction. Ground models were created as a triangulated surface and exported as ArcInfo ASCII grids at a 3-foot pixel resolution. Software - TerraScan v.9.001, ArcMap v.9.3, TerraModeler v.9.001
    • The NOAA Coastal Services Center (CSC) downloaded topographic files in LAZ format from PSLC's website. The files contained lidar easting, northing, elevation, intensity, return number, class, scan angle and GPS time measurements; the data was received in state plane Washington North (in feet) and vertical coordinates were referenced to NAVD88 in feet using the Geoid03 model. CSC performed the following processing for data storage and Digital Coast provisioning purposes: 1. The All-Return LAZ files were checked for bad elevations 2. The laz files were converted from a Projected Coordinate System (SP 4601) to a Geographic Coordinate system (NAD83) 3. The laz files were then converted to ellipsoidal vertical units in meters using the geoid03 conversion.
    • 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: 2013-12-06

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