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2005 Hancock and Jackson Counties, MS Lidar

This metadata record describes the topographic mapping of Hancock and Jackson Counties, Mississippi during 2005. Using a combination of laser rangefinding, GPS positioning and inertial measurement technologies; LIDAR instruments are able to make highly detailed Digital Elevation Models (DEMs) of the earth's terrain, man-made structures and vegetation. This data was collected at submeter resolution to provide nominal 5m spacing of collected points. Multiple returns were recorded for each pulse in addition to an intensity value using a Leica ALS-50 Aerial Lidar Sensor.

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 DOC/NOAA/NOS/CSC > Coastal Services Center, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    843-740-1200
    csc.info@noaa.gov
    Associated Resources
    • Lidar QA/QC Report
    Originator
    • DOC/NOAA/NOS/CSC > Coastal Services Center, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Publisher
    • DOC/NOAA/NOS/CSC > Coastal Services Center, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Date(s)
    • publication: 2006-10-19
    Data Presentation Form: Digital image
    Dataset Progress Status Complete
    Data Update Frequency: Not planned
    Purpose: These data were originally collected to support flood plain mapping and other coastal management applications.
    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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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: 2005-02-25  to  2005-03-01
    Spatial Reference System: urn:ogc:def:crs:EPSG::4269 Ellipsoid in Meters
    Spatial Bounding Box Coordinates:
    N: 30.740893
    S: 30.169006
    E: -88.388259
    W: -89.695649
    Spatial Coverage Map:
    Themes
    • Bathymetry/Topography
    • elevation
    • lidar
    • laser
    • beach
    • topography
    • digital elevation model
    • DEM
    • erosion
    Places
    • Mississippi
    • Hancock County
    • Jackson County
    Use Constraints No constraint information available
    Fees Fee information not available.
    Source Datasets
    • Report of Survey - Hancock & Jackson Counties Mississippt
      • Description of Source: Source Contribution: Ground Control. Kevin Chappell, of Terrasurv and under contract to EarthData International established at total of 40 survey points within Jackson and Hancock Counties, MS. The survey was completed in two phases; the first phase consisted of 8 lidar control points in southern Jackson County. The second phase consisted of 12 additional lidar control points in Jackson County and 20 new lidar control points in Hancock County. Source Type: electronic mail system
      • Temporal extent used:  2005-03-01  to  2005-06-22
    • Aerial Lidar Acquisition over Jackson County, MS
      • Description of Source: Source Contribution: Aerial Lidar Acquisition. EarthData Aviation., was contracted by EarthData International to collect ALS-50 Lidar data over Hancock and Jackson Counties, Mississippi. The project site was flown on February 25 and March 1, 10, 11, and 12 using its aircraft with tail number N2636P. Lidar data was captured using an ALS-50 Lidarsystem, including an inertial measuring unit (IMU) and a dual frequency GPS receiver. Lidar was obtained at an altitude of 3,658 meters (12,000 feet) above mean terrain, at an average airspeed of 145 knots. Sensor pulse rate was set at 29,900 Hz with a field of view of 45 degrees and a scan rate of 17 Hz. Average swath width of the collected raw lines is 3,100 meters. Point spaing was 5 meters. Lidar data was recorded in conjunction with airborne GPS and IMU; the stationary GPS receiver was positioned over a control point located at the airport. Recorded digital data was shipped via external hard drive to the production facility for processing. During airborne data collection, an additional GPS receiver was in constant operation over a published National Geodetic Survey (NGS) control point at at KHSA (Stennis International) Airport. The coordinate value for temporary control point STENNIS (BH2999) was determined by a network adjustment to CORS stations MOB1 and NDBC , both of which were tied to the project control network. During the data acquisition, the receivers collected phase data at an epoch rate of 1 Hz. All GPS phase data was post processed with continuous kinematic survey techniques using "On the Fly" (OTF) integer ambiguity resolution. The GPS data was processed with forward and reverse processing algorithms. The results from each process, using the data collected at the airport, were combined to yield a single fixed integer phase differential solution of the aircraft trajectory. Source Type: Firewire Drive
      • Temporal extent used:  2005-02-25  to  2005-03-01
    Lineage Statement Lineage statement not available.
    Processor
    • EarthData International
    • 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
    • EarthData has developed a unique method for processing lidar data to identify and remove elevation points falling on vegetation, buildings, and other above ground structures. The algorithms for filtering data were utilized within EarthData's proprietary software and commercial software written by TerraSolid. This software suite of tools provides efficient processing for small to large-scale, projects and has been incorporated into ISO 9001 compliant production work flows. The following is a step-by-step breakdown of the process. 1. Using the lidar data set provided by EarthData, the technician performs calibrations on the data set. 2. Using the lidar data set provided by EarthData, the technician performed a visual inspection of the data to verify that the flight lines overlap correctly. The technician also verified that there were no voids, and that the data covered the project limits. The technician then selected a series of areas from the data set and inspected them where adjacent flight lines overlapped. These overlapping areas were merged and a process which utilizes 3-D Analyst and EarthData's proprietary software was run to detect and color code the differences in elevation values and profiles. The technician reviewed these plots and located the areas that contained systematic errors or distortions that were introduced by the lidar sensor. 3. Systematic distortions highlighted in step 2 were removed and the data was re-inspected. Corrections and adjustments can involve the application of angular deflection or compensation for curvature of the ground surface that can be introduced by crossing from one type of land cover to another. 4. The lidar data for each flight line was trimmed in batch for the removal of the overlap areas between flight lines. The data was checked against a control network to ensure that vertical requirements were maintained. Conversion to the client-specified datum and projections were then completed. The lidar flight line data sets were then segmented into adjoining tiles for batch processing and data management. 5. The initial batch-processing run removed 95% of points falling on vegetation. The algorithm also removed the points that fell on the edge of hard features such as structures, elevated roadways and bridges. 6. The operator interactively processed the data using lidar editing tools. During this final phase the operator generated a TIN based on a desired thematic layers to evaluate the automated classification performed in step 5. This allowed the operator to quickly re-classify points from one layer to another and recreate the TIN surface to see the effects of edits. Geo-referenced images were toggled on or off to aid the operator in identifying problem areas. The data was also examined with an automated profiling tool to aid the operator in the reclassification. 6. The final DEM was written to an ESRI grid format (.flt). 7. The point cloud data were also delivered in LAS format. 8. Project data was clipped to a 500-meter buffer outside of the official project boundary.
    • The NOAA Coastal Services Center (CSC) received files in LAS format. The files contained LiDAR intensity and elevation measurements. CSC performed the following processing on the data to make it available within the LiDAR Data Retrieval Tool (LDART) 1. The las files were converted from UTM coordinates to Geographic coordinates. 2. The las header fields were sorted by latitude and updated. For data management purposes, the Coastal Services Center converted the data from NAVD88 elevations to ellipsoid elevations using Geoid 03.
    • 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: 2013-05-07

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