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2012 Georgia Department of Natural Resources (GADNR) Topographic LiDAR: Floyd, Polk, Paulding and Oconee Counties

browse graphicThis graphic shows the lidar coverage for Polk County, Paulding County, Floyd County and Oconee County in Georgia.
TASK NAME:FY 2012 GEORGIA DNR ELEVATION DATA NOAA Contract No. EA133C11CQ0010 Requisition No. NCNP0000-11-02615 Woolpert Order No. 71511 CONTRACTOR: Woolpert, Inc. The PSFY12 GADNR Elevation Data Task Order involves: collecting and delivering topographic elevation point data derived from multiple return light detection and ranging (LiDAR) measurements for portions of 4 counties in Georgia. The Statement of Work (SOW) was developed by the National Oceanic and Atmospheric Administration's (NOAA) Coastal Services Center (referred to as the Center) in partnership with the Georgia Department of Natural Resources (GADNR) Environmental Protection Division (EPD). The counties included Floyd, Polk, Paulding and Oconee. The purpose of the data is for use in coastal management decision making, including applications such as flood plain mapping and water rights management. LiDAR was collected at 1.0 points per square meter (1.0m GSD) for the portions of Floyd, Polk, Paulding and Oconee Counties. This area was flown during snow free and leaf-off conditions.

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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 National Oceanic and Atmospheric Administration (NOAA)
    (843) 740-1200
    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
    • Georgia Department of Natural Resources (GADNR)
    Publisher
    • DOC/NOAA/NOS/CSC > Coastal Services Center, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Date(s)
    • publication: 2012-09-23
    Data Presentation Form: Digital image
    Dataset Progress Status Complete
    Data Update Frequency: As needed
    Supplemental Information: The reflective surface data represents the DEM created by the laser energy reflected from the first surface encountered by the laser pulse. Some energy may continue beyond this initial surface, to be reflected by a subsequent surface as represented by the last return data. Intensity information is captured from the reflective surface pulse and indicates the relative energy returned to the sensor, as compared to the energy transmitted. The intensity image is not calibrated or normalized but indicates differences in energy absorption due to the interaction of the surface materials with laser energy, at the wavelength transmitted by the sensor. The bare earth model is created by identifying the returns that fall on the ground surface and by interpolating a surface between these points. In this manner, buildings and vegetation are removed from the bare earth model. This data set does not include bridges and overpasses in the bare earth model as the delineation point for these structures is not reliably discernable in the LiDAR data.
    Purpose: This task order consisted of LiDAR data acquisition and processing for the National Oceanic and Atmospheric Administration's (NOAA) Coastal Services Center (CSC) four Counties in Georgia: Floyd, Oconee, Paulding and Polk. The LiDAR data acquisition and processing for Floyd, Oconee, Paulding and Polk Counties was performed in the Spring of 2012. The LiDAR data was provided to NOAA CSC, as part of the FY 2012 Georgia Elevation Data task order. The task order area for Floyd, Polk, and Paulding Counties was approximately 460.6 square miles, and the task order area for Oconee County was approximately 233.6 square miles The LiDAR data was collected to meet Fundamental Vertical Accuracy (FVA) Root Mean Square Error (RMSE) of 18.0 cm or better at a 95% confidence level, so that when combined with breaklines, the data adequately supports the generation of two (2) foot FEMA compliant contours. The final LiDAR data was delivered in 5,000' x 5,000' tiles using NAD 1983 (NSRS2007), Georgia State Plane Coordinate System, West Zone 1002.
    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: 2012-03-06  to  2012-03-26
    Spatial Reference System: urn:ogc:def:crs:EPSG::4269 Ellipsoid in Meters
    Spatial Bounding Box Coordinates:
    N: 34.367865
    S: 33.681195
    E: -83.249536
    W: -85.263140
    Spatial Coverage Map:
    Themes
    • Topography/Bathymetry
    • Elevation
    • Lidar
    • LAS
    Places
    • United States
    • Georgia
    • Floyd County
    • Oconee County
    • Paulding County
    • Polk County
    Use Constraints No constraint information available
    Fees Fee information not available.
    Lineage Statement Lineage statement not available.
    Processor
    • Woolpert, Inc.
    • 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
    • Using a Leica LiDAR system, 84 flight lines of high density data, at a nominal pulse spacing (NPS) of 1.0 meter, were collected over Floyd, Oconee, Paulding and Polk Counties, GA (approximately 694.2 square miles). Multiple returns were recorded for each laser pulse along with an intensity value for each return. A total of five (5) missions were flown on March 6, 19, 20, 25 and 26 in 2012. The geoid used to reduce satellite derived elevations to orthometric heights was Geoid09. The horizontal datum used for this survey is NAD 1983 NSRS2007, Georgia State Plane Coordinate System, West Zone 1002, and expressed in US Survey Feet. The vertical datum used for this survey is North American Vertical Datum 1988 (NAVD88), and expressed in US Survey Feet. Airborne GPS data was differentially processed and integrated with the post processed IMU data to derive a smoothed best estimate of trajectory (SBET). The SBET was used to reduce the LiDAR slant range measurements to a raw reflective surface for each flight line. The aerial LiDAR was collected at the following sensor specifications for the Oconee County Project: Post Spacing (Minimum): 3.28 ft / 1.0 m AGL (Above Ground Level) average flying height: 6,500 ft / 1,981 m MSL (Mean Sea Level) average flying height: 6,940 ft / 2,115 m Average Ground Speed: 130 knots / 149 mph Field of View (full): 40 degrees Pulse Rate: 115.6 kHz Sensor Scan Rate: 41.8 Hz Side Lap (Minimum): 25% Flight Lines Flown at these specifications: 1 - 27 (All) The aerial LiDAR was collected at two different sensor specifications for the Floyd, Polk, and Paulding Counties Project: Those LIDAR flight lines that entered the Atlanta Class B Airspace restriction area were flown at a lower altitude specification in order to maintain an altitude of 6500 feet MSL. These instructions were mandated by Atlanta Tracon. Post Spacing (Minimum): 3.28 ft / 1.0 m AGL (Above Ground Level) average flying height: 6,500 ft / 1,981 m MSL (Mean Sea Level) average flying height: 7,075 ft / 2,156 m Average Ground Speed: 130 knots / 149 mph Field of View (full): 40 degrees Pulse Rate: 115.6 kHz Sensor Scan Rate: 41.8 Hz Side Lap (Minimum): 25% Flight Lines Flown at these specifications: 1 - 20 Post Spacing (Minimum): 3.28 ft / 1.0 m AGL (Above Ground Level) average flying height: 5,925 ft / 1,825 m MSL (Mean Sea Level) average flying height: 6,500 ft / 1,981 m Average Ground Speed: 130 knots / 149 mph Field of View (full): 44 degrees Pulse Rate: 124.0 kHz Sensor Scan Rate: 43.1 Hz Side Lap (Minimum): 25% Flight Lines Flown at these specifications 21 - 57
    • The Leica ALS50/60 LiDAR systems calibration and performance is verified on a periodic basis using Woolpert's calibration range. The calibration range consists of a large building and runway. The edges of the building and control points along the runway have been located using conventional survey methods. Inertial measurement unit (IMU) misalignment angles and horizontal accuracy are calculated by comparing the position of the building edges between opposing flight lines. The scanner scale factor and vertical accuracy is calculated through comparison of LiDAR data against control points along the runway. Field calibration is performed on all flight lines to refine the IMU misalignment angles. IMU misalignment angles are calculated from the relative displacement of features within the overlap region of adjacent (and opposing) flight lines. The raw LiDAR data is reduced using the refined misalignment angles.
    • Once the data acquisition and GPS processing phases are complete, the LiDAR data was processed immediately to verify the coverage had no voids. The GPS and IMU data was post processed using differential and Kalman filter algorithms to derive a best estimate of trajectory. The quality of the solution was verified to be consistent with the accuracy requirements of the task order.
    • The individual flight lines were inspected to ensure the systematic and residual errors have been identified and removed. Then, the flight lines were compared to adjacent flight lines for any mismatches to obtain a homogenous coverage throughout the project area. The point cloud underwent a classification process to determine bare-earth points and non-ground points utilizing "first and only" as well as "last of many" LiDAR returns. This process determined bare-earth points (Class 2), noise (Class 7), water (Class 9) ignored ground (Class 10), unclassified data (Class 1), and overlap points (Class 12). The bare-earth (Class 2 - Ground) LiDAR points underwent a manual QA/QC step to verify that artifacts have been removed from the bare-earth surface. The surveyed ground control points are used to perform the accuracy checks and statistical analysis of the LiDAR dataset.
    • 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 Georgia State Plane West 1002 (NAD83) coordinates and were vertically referenced to NAVD88 using the Geoid09 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 converted from orthometric (NAVD88) heights to ellipsoidal heights using Geoid09. 2. The topographic las files' vertical units were converted from survey feet to meters. 3. The topographic las files were converted from a Projected Coordinate System (GA SPW 1002) to a Geographic Coordinate system (GCS). 4. The topographic las files' horizontal units were converted from survey feet to decimal degrees. 5. 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: 2013-01-22

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