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2011 U.S. Geological Survey (USGS) Alabama Topographic LiDAR: Baldwin County East and West

browse graphicThis kmz file shows the extent of coverage for the 2011 USGS Balwin County, AL lidar data.
USGS Contract: G10PC00026 Task Order Number: G10PD02126 LiDAR was collected at a 2.0 meter nominal post spacing (2.0m GSD) for approximately 329 square miles of Baldwin County, Alabama, while no snow was on the ground and rivers were at or below normal levels. Project was divided into two separate AOIs, Baldwin West and Baldwin East. Project meets U.S. Geological Survey National Geospatial Program Base LiDAR Specification, Version 13. LAS Classifications: Class 1: Unclassified Class 2: Bare Earth Ground Class 5: High Vegetation Class 7: Noise (Low points) Class 9: Water Class 10: Ignored Ground (within 1m of breakline) Class 12: Overlap Class 13: Witheld

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 Patrick Emmett
    USGS/NGTOC
    573-308-3587
    pemmett@usgs.gov
    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
    • DOI/USGS > United States Geological Survey, U.S. Department of Interior
    Publisher
    • DOC/NOAA/NOS/CSC > Coastal Services Center, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Date(s)
    • publication: 2013-01-01
    Data Presentation Form: Digital image
    Dataset Progress Status Complete
    Data Update Frequency: As needed
    Purpose: Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create Intensity Images, Break Lines and Raster DEMs.
    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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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: 2011-01-22  to  2011-01-28
    Spatial Reference System: urn:ogc:def:crs:EPSG::4269 Ellipsoid in Meters
    Spatial Bounding Box Coordinates:
    N: 30.865296
    S: 30.298128
    E: -87.354075
    W: -88.045250
    Spatial Coverage Map:
    Themes
    • Topography/Bathymetry
    • Elevation
    • LiDAR
    • LAS
    • remote sensing
    Places
    • Baldwin County
    • Alabama
    • US
    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
    • Applanix software was used in the post processing of the airborne GPS and inertial data that is critical to the positioning and orientation of the sensor during all flights. POSPac MMS provides the smoothed best estimate of trajectory (SBET) that is necessary for Optech'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 Optech 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. The Baldwin County project (G10PD02126) is immediately adjacent to the NGOM Mobile Bay LiDAR project (G10PD00578). A manual review was performed to ensure that the two datasets tied together as seemlessly as possible. Revisions were made to both the LAS and breakline datasets as needed in order to achieve a smooth transition between the two datasets. NGOM Mobile Bay data was used to produce full tile deliverables on the eastern edge of the Baldwin County West dataset and the western edge of the Baldwin County East dataset. Upon completion of the Baldwin County deliverables, revised copies of the NGOM deliverables that border the Baldwin dataset will be provided in order to ensure that the two datasets agree with each other. All Class 2 LiDAR data inside of the collected breaklines were then classified to Class 9 using TerraScan macro functionality. A buffer of 1 meter was also used around each hydro flattened feature. The breakline files were then translated to ESRI Shapefile format using ESRI conversion tools. Data was then run through additional macros to ensure deliverable classification levels matching LAS ASPRS Classification structure. GeoCue functionality was then used to ensure correct LAS Version. In house software was used as a final QA/QC check to provide LAS Analysis of the delivered tiles.
    • The NOAA Coastal Services Center (CSC) received topographic files in LAS format. The files contained lidar elevation and intensity measurements. The data were received in UTM Zone 16 (NAD83) coordinates and were vertically referenced to NAVD88 using the Geoid09 model. The vertical units of the data were meters. CSC performed the following processing for data storage and Digital Coast provisioning purposes: 1. The topographic las files were converted from orthometric (NAVD88) heights to ellipsoidal heights using Geoid09. 2. The topographic las files were horizontally converted from UTM coordinates (m) to NAD83 Geographic coordinates (dd). 3. ASPRS Class 11 (Witheld) was changed to Class 13 (Witheld). 4. 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: 2013-03-28

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