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2004 Puget Sound LiDAR Consortium (PSLC) Topographic LiDAR: Portland, Oregon

browse graphicThis kmz file shows the extent of coverage for the 2004 PSLC Portland, OR lidar data set.
The all returns ASCII files contain the X,Y,Z values of all the LiDAR returns collected during the survey mission. In addition each return also has a time stamp, return number, ellipsoidal height and scan angle. The elevation values are in feet. TerraPoint surveyed and created this data for the Puget Sound LiDAR Consortium under contract. This data set covers 120 square miles. The LAS files were derived from all returns ASCII files contain the X,Y,Z values of all the LiDAR returns collected during the survey mission. The standard GPS time, scan angle, and return numbers of each point were preserved in the conversion from ASCII to LAS. The LAS files were classified by the NOAA CSC using an unsupervised algorithm. No warranty is made as to the accuracy of the classification. Futher details are available in the Process Steps below.

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: 2013-06-01
    Data Presentation Form: Digital image
    Dataset Progress Status Complete
    Data Update Frequency: As needed
    Purpose: The LiDAR all returns ASCII files can be used to create DEM and also to extract topographic data in software that does not support raster data. Other surface features can also be extracted with custom applications. This high accuracy data can be used at scales up to 1:12000 (1 inch = 1,000 feet). LiDAR 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: 2004-03-07  to  2004-03-13
    Spatial Reference System: urn:ogc:def:crs:EPSG::4269 Ellipsoid in Meters
    Spatial Bounding Box Coordinates:
    N: 45.500000
    S: 45.212772
    E: -122.511076
    W: -122.750000
    Spatial Coverage Map:
    Themes
    • Topography/Bathymetry
    • Elevation
    • Model
    • LiDAR
    • LAS
    • Remote Sensing
    Places
    • US
    • Oregon
    • Multnomah County
    • Clackamas County
    • Portland
    • Tryon Creek Watershed
    • Willamette River
    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, 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
    • ASCII file generation All Point returns with all their attributes were directly exported into ASCII files. These were first divided into USGS quarter quads (3.25 minute by 3.25 minute) and then in 25 tiles per quarter quad.
    • The NOAA Coastal Services Center (CSC) received topographic files in ASCII .TXT format. The files contained lidar elevation measurements. The data were received in Oregon State Plane North Zone 3601, 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 ASCII .TXT files were run through a parser to convert GPS Week Time to Adjusted Standard GPS Time. 2. The parsed ASCII .TXT files were converted to LAS version 1.2 using LAStools' txt2las tool. 3. Total Number of Returns information was not avaiable, so all points were given a Total Number of Returns value of 4. 4. The LAS files were classified into Class 1 (Unclassified) and Class 2 (Ground) using LASTool's lasground tool. 5. The topographic las files were converted from orthometric (NAVD88) heights to ellipsoidal heights using Geoid99. 6. The topographic las files were converted from a Projected Coordinate System (OR SP North) to a Geographic Coordinate system (NAD 83). 7. The topographic las files' vertical units were converted from feet to meters. 8. The topographic las files' horizontal units were converted from feet to decimal degrees. 9. 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: 2013-06-28

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