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2009 U.S. Geological Survey (USGS) Topographic LiDAR: Androscoggin County, Maine

browse graphicThis kmz file shows the extent of coverage for the 2009 USGS Androscoggin, ME lidar data set.
USGS Contract Number: G10PC00026 USGS Task Order: G10PD01737 LiDAR was collected at a 1.0 points per square meter (1.0m GSD) for the county of Androscoggin, Maine while no snow was on the ground and rivers were at or below normal levels and prior to leaf-on conditions.

Cite this dataset when used as a source.

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    Distribution Formats
    • LAZ
    Distributor Distributor information not available
    Point of Contact Robert Kelly
    United States Geological Survey, National Geospatial Technical Operations Center (NGTOC)
    Documentation links not available.
    • DOI/USGS > United States Geological Survey, U.S. Department of the Interior
    • DHS/FEMA > Federal Emergency Management Agency, U.S. Department of Homeland Security
    • Strategic Alliance for Risk Reduction (STARR)
      • publication: 2013-04-01
      Data Presentation Form: Digital image
      Dataset Progress Status Complete
      Data Update Frequency: As needed
      Purpose: One meter point spacing LiDAR data collection provides the information to create Intensity Images, Break Lines, Raster DEMs, and fully Classified LiDAR LAS files.
      Time Period: 2009-11-17  to  2009-12-02
      Spatial Reference System:
      Spatial Bounding Box Coordinates:
      N: 44.493105
      S: 43.903320
      E: -69.986657
      W: -70.405713
      Spatial Coverage Map:
      • Bathymetry/Topography
      • Remote Sensing
      • Elevation
      • LiDAR
      • LAS
      • Digital Elevation Model
      • Digital Surface Model
      • US
      • Maine
      • Androscoggin County
      Use Constraints No constraint information available
      Fees Fee information not available.
      Lineage Statement Lineage statement not available.
      Processing Steps
      • Leica software was used in the post processing of the airborne GPS and inertial data that is critical to the positioning of the sensor during all flights. This software suite includes Applanix's PosPac and Waypoint's GrafNav solutions. PosPac provides the smoothed best estimate of trajectory (SBET) that is necessary for Leica's post processor to develop the point cloud from the LiDAR missions. The point cloud is the mathematical three dimensional collection of all returns from all laser pulses as determined from the aerial mission. At this point this data is ready for analysis, classification, and filtering to generate a bare earth surface model in which the above ground features are removed from the data set. The point cloud was manipulated within the Leica software; GeoCue, TerraScan, and TerraModeler software was used for the automated data classification, manual cleanup, and bare earth generation from this data. Project specific macros were used to classify the ground and to remove the side overlap between parallel flight lines. All data was manually reviewed and any remaining artifacts removed using functionality provided by TerraScan and TerraModeler. Buffered LAS files were created in GeoCue to provide overedge to the DEM creation. These tiles were then run through automated scripting within ArcMap and were combined with the Hydro Flattened Breaklines to create the 2.5 foot DEM. Final DEM tiles were clipped to the tile boundary to provide a seamless dataset. ERDAS IMG files were then created as the project deliverable. A manual QA review of the tiles was completed in ArcMap and Global Mapper to ensure full coverage with no gaps or slivers within the project area.
      • The NOAA Coastal Services Center (CSC) received topographic files in the compressed LAS.GZ format. The files contained lidar elevation and intensity measurements. The data were received in Projected Coordinates (Maine State Plane West 1802) and were vertically referenced to NAVD88 using the Geoid03 model. The vertical units of the data were feet. CSC performed the following processing for data storage and Digital Coast provisioning purposes: 1. The topographic LAS files were uncompressed using gunzip. 2. The topographic LAS files were converted from Projected coordinates (Maine State Plane West) to Geographic Coordinates (NAD83). 3. The horizontal units of the topographic LAS files were converted from feet to decimal degrees. 4. The topographic LAS files were converted from orthometric (NAVD88) heights to ellipsoidal heights (NAD83) using Geoid03. 5. The vertical units of the topographic LAS files were converted from feet to meters. 6. 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 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: 2013-05-17

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