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2004 Puget Sound Lidar Consortium (PSLC) Topographic Bare-Earth Lidar: Pierce County, WA

browse graphicThis kmz file shows the extent of coverage for the 2004 PSLC Pierce County, WA lidar data set.
Terrapoint surveyed and created this data for the Puget Sound LiDAR Consortium under contract. The project area covers approximately 814 square miles of western Pierce County. A majority of the data was collected between January 21st and March 08, 2004. Two small areas were reflown during spring 2005.

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
    Documentation links not available.
    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: 2013-08-01
    Data Presentation Form: Digital image
    Dataset Progress Status Complete
    Data Update Frequency: As needed
    Purpose: The LiDAR bare earth ASCII files can be used to create DEM and also to extract topographic data in software that does not support raster data. This high accuracy data can be used at scales up to 1:12000 (1 inch = 1,000 feet). The LiDAR bare earth data has a wide range of uses such as earthquake hazard studies, hydrologic modeling, forestry, coastal engineering, roadway and pipeline engineering, flood plain mapping, wetland studies, geologic studies and a variety of analytical and cartographic projects.
    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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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: 2004-01-24  to  2004-03-08
    Spatial Reference System: urn:ogc:def:crs:EPSG::4269 Ellipsoid in Meters
    Spatial Bounding Box Coordinates:
    N: 47.321118
    S: 46.743235
    E: -121.910870
    W: -122.696132
    Spatial Coverage Map:
    Themes
    • Topography/Bathymetry
    • Elevation
    • Model
    • LiDAR
    • LAS
    • Remote Sensing
    • Bare Earth
    • ground surface
    Places
    • US
    • Washington
    • Pierce 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. Lidar data were collected in leaf-off conditions (approximately 1 November - 1 April) from a fixed-wing aircraft flying at a nominal height of 1,000 meters above ground surface. Aircraft position was monitored by differential GPS, using a ground station tied into the local geodetic framework. Aircraft orientation was monitored by an inertial measurement unit. Scan angle and distance to target were measured with a scanning laser rangefinder. Scanning was via a rotating 12-facet pyramidal mirror; the laser was pulsed at 30+ KHz, and for most missions the laser was defocussed to illuminate a 0.9m-diameter spot on the ground. The rangefinder recorded up to 4 returns per pulse. Flying height and airspeed were chosen to result in on-ground pulse spacing of about 1.5 m in the along-swath and across-swath directions. Most areas were covered by two swaths, resulting in a nominal pulse density of about 1 per square meter.
    • Processing. GPS, IMU, and rangefinder data were processed to obtain XYZ coordinates of surveyed points. For data acquired after January, 2003 (NW Snohomish, Mt Rainier, Darrington, and central Pierce projects), survey data from areas of swath overlap were analysed to obtain best-fit in-situ calibration parameters that minimize misfit between overlapping swaths. This reduces vertical inconsistency between overlappoing swaths by about one-half. Heights were translated from ellipsoidal to orthometric (NAVD88) datums via GEOID99
    • Post-processing. Return points were then classified semi-automatically as ground (and water), not-ground (vegetation and structures) and blunder. For 2000 and 2001 data, the despike virtual deforestation algorithm described by Haugerud and Harding (2001) was used. After 2001, TerraPoint shifted to Terrascan software, which includes additional classification algorithms, allows for greater intervention by a human operator, and generally produces better bare-earth surface models.
    • ASCII file generation The X,Y,Z values of the ground returns were exported into ASCII files. These were divided into USGS quarter quads (3.25 minute by 3.25 minute).
    • Breakng down ASCII files TerraPoint shipped data in USGS quarter-quads (3.25 minute by 3.25 minute). To reduce the file size and make them more user friendly, each quarter quad files was further broken down into 25 smaller tiles.
    • The NOAA Coastal Services Center (CSC) received topographic files in ASCII .txt format. The files contained lidar elevation measurements only. The data were received in Washington State Plane North Zone 4601, NAD83 coordinates and were vertically referenced to NAVD88 using the Geoid99 model. The vertical units of the data were feet. CSC performed the following processing for data storage and Digital Coast provisioning purposes: 1. The parsed ASCII .txt files were converted to LAS version 1.2 using LAStools' txt2las tool. 2. The topographic las files' classifications off all points were changed from Class 0 (Never Classified) to Class 2 (Ground). 3. The topographic las files were converted from orthometric (NAVD88) heights to ellipsoidal heights using Geoid99. 4. The topographic las files were converted from a Projected Coordinate System (WA SP North) to a Geographic Coordinate system (NAD 83). 5. The topographic las files' vertical units were converted from feet to meters. 6. The topographic las files' horizontal units were converted from feet to decimal degrees. 7. 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: 2013-10-17

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