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2008 USACE Great Lakes Topo/Bathy Lidar: Lake Huron, Michigan

These files contain topographic and bathymetric lidar data collected by the Compact Hydrographic Airborne Rapid Total Survey (CHARTS) system along the Lake Huron coast of Michigan in Huron, Sanilac, and St. Clair Counties during August 12-17, 2008. CHARTS integrates topographic and bathymetric lidar sensors, a digital camera, and a hyperspectral scanner on a single remote sensing platform for use in coastal mapping and charting activities. Data coverage generally extends along the coastline from the waterline inland 500 meters (topography) and offshore 1,000 meters or to laser extinction (bathymetry). The topographic lidar sensor has a pulse repetition rate of 9 kHz at 1064 nm (near-infrared wavelength). The bathymetric lidar sensor has a pulse repetition rate of 1 kHz at 532 nm (green wavelength). Native lidar data is not generally in a format accessible to most Geographical Information Systems (GIS). Specialized in-house and commercial software packages are used to process the native lidar data into 3-dimensional positions that can be imported into GIS software for visualization and further analysis. Horizontal positions, provided in decimal degrees of latitude and longitude, are referenced to the North American Datum of 1983 (NAD83). Vertical positions are referenced to the NAD83 ellipsoid and provided in meters. The National Geodetic Survey's (NGS) GEOID03 model is used to transform the vertical positions from ellipsoid to orthometric heights referenced to the North American Vertical Datum of 1988 (NAVD88). Upon receipt at the NOAA Coastal Services Center, the data were converted to las format and to ellipsoid heights using GEOID03 for data storage and Digital Coast provisioning purposes. Additionally, the bathymetric lidar data points were classified according to the ASPRS LAS 1.2 classification scheme as 11 (bathymetry) and the topographic last return lidar data points were classified as 1 (unclassified).

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    • LAZ
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      • publication: 2011-07-01
      Data Presentation Form: Digital image
      Dataset Progress Status Complete
      Data Update Frequency: As needed
      Supplemental Information: Sensor malfunction in the survey area hindered the acquisition of bathymetric data in boxes 08, 09, 10, and 11 which and resulted in incomplete coverage.
      Purpose: These data were collected as a part of the NCMP (National Coastal Mapping Program) to depict the elevations ABOVE AND/OR BELOW the water for the First Return OR Last Return OR Hydro in the Michigan coastal zone.
      Time Period: 2008-08-12  to  2008-08-17
      Spatial Reference System:
      Spatial Bounding Box Coordinates:
      N: 44.057515
      S: 42.999615
      E: -82.413509
      W: -82.880709
      Spatial Coverage Map:
      • Bathymetry/Topography
      • U.S. Army Corps of Engineers, Mobile District
      • JALBTCX
      • CHARTS
      • SHOALS
      • Topography
      • Bathymetry
      • ASCII XYZ
      • Lidar
      • United States
      • Michigan
      • Huron County
      • Saint Clair County
      • Sanilac County
      • Bay City
      • Port Huron
      Use Constraints No constraint information available
      Fees Fee information not available.
      Lineage Statement Lineage statement not available.
      Processing Steps
      • These data were collected using the CHARTS system. It is owned by the Naval Oceanographic Office and operated through contract. The system collects topographic lidar data at 9 kHz, bathymetric lidar data at 1 kHz and RGB imagery at 1 Hz. A CASI-1500 hyperspectral line scanner is integrated with the system as well. Aircraft position, velocity and acceleration information are collected through a combination of Novatel and POS A/V 410 equipment. All raw data streams are transferred to the office for downloading and processing in SHOALS GCS software. Aircraft position data are processed using POSPac software and the results are combined with the lidar data to produce 3-D positions for each lidar shot. Upon inspection and QA/QC in the software packages Fledermaus and PFM_ABE, anomalous data are flagged as invalid. PFM_ABE's chartsLAS module then converts all valid data from ellipsoid to orthometric heights based on the NGS' GEOID03 model and exports data as a series of first return topography (TF), last return topography (TL) and bathymetry (H) ASCII files. The bathymetry files contain all of the returns from the bathymetric sensor which include returns both above and below the water.
      • The NOAA Coastal Services Center (CSC) received unclassified files in ASCII format. The files contained LiDAR intensity and elevation measurements. CSC performed the following processing on the data for data storage and Digital Coast provisioning purposes: 1. The data (topographic last return and hydrographic lidar points) were converted from ASCII format to las format. 2. The data were converted from NAVD88 heights to ellipsoid heights using GEOID03. 3. The hydrographic lidar data points were classified according to the ASPRS LAS 1.2 classification scheme as 11 (bathymetry) and the topographic last return lidar data points were classified as 1 (unclassified). 4. The LAS header fields were sorted by latitude and updated.
      • Times had originally been stored as POSIX seconds when converted to LAS. This was switched to adjusted GPS time (GPS seconds - 1e9) to conform to the LAS 1.2 standard. The data were also 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 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 ( 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: 2014-03-14

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