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2006 Federal Emergency Management Agency (FEMA) Topographic LiDAR: Cumberland and York Counties, Maine

browse graphicThis kmz file shows the extent of coverage for the 2006 FEMA Cumberland and York Counties, ME lidar data set.
In the fall of 2006, Sanborn Map Company was contracted by Camp Dresser McKee, Inc (CDM) to execute a LiDAR (Light Detection and Ranging) survey campaign in the state of Maine. LiDAR data in the form of 3-dimensional positions of a dense set of masspoints was collected for the 584 sqaure miles of Cumberland and York Counties. This data was used in the development of the bare-earth-classified elevation point data sets. The Leica ALS-50 LiDAR system was used to collect data for the whole survey campaign. The LiDAR system is calibrated by conducting flight passes over a known ground surface before and after each LiDAR mission. During final data processing, the calibration parameters are inserted into post-processing software. Six airborne GPS (Global Positioning System) base stations were used in this project. A new point was set at the Portland Airport (501) The other base stations were set up at National Geodetic Survey (NGS) markers. NGS Monuments 901- PID: OC0229 and 801 - PID: OC0230 are located at the Biddeford Airport. The other existing NGS monuments used in the network are point 701 - PID: AJ2697, located on Bailey Island, point 702 - PID: OC0429, located at Fort Constitution, and point 703 - PID: OC0478 located southeast of York Beach were tied to the other three points to create a GPS survey network. The coordinates of these stations were checked against each other with the three dimensional GPS baseline created at the airborne support set up and determined to be within project specifications. Leica ALS-50 LiDAR Scanner Parameters: Pulse Rate: 50,000 hertz Scan Frequency: 36 hertz Scan Width (Half Angle): 18 degrees Flying Height: 1,200 meters above ground level Flying Speed: ~120 knots

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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 Federal Emergency Management Agency, Region I
    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
    • DHS/FEMA > Federal Emergency Management Agency, U.S. Department of Homeland Security
    Publisher
    • DOC/NOAA/NOS/CSC > Coastal Services Center, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Date(s)
    • publication: 2013-04-15
    Data Presentation Form: Digital image
    Dataset Progress Status Complete
    Data Update Frequency: As needed
    Purpose: The LIDAR derived data sets, including Bare Earth and a Gridded DEM support Camp Dresser and McKee's continued development of updated Digital Flood Insurance Rate Maps and flood insurance studies for coastal areas located in Cumberland and York Counties, Maine. Acquisition is Tide restricted to +/- 3 hours from Low tide.(Source: FEMA Guidelines and Specs, Appendix N).
    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: 2006-10-07  to  2006-10-27
    Spatial Reference System: urn:ogc:def:crs:EPSG::4269 Ellipsoid in Meters
    Spatial Bounding Box Coordinates:
    N: 43.980053
    S: 43.052971
    E: -69.842006
    W: -70.842773
    Spatial Coverage Map:
    Themes
    • Topography/Bathymetry
    • Elevation
    • Digital Terrain Model
    • Digital Surface Model
    • LiDAR
    • LAS
    • Remote Sensing
    Places
    • US
    • Maine
    • Cumberland County
    • York County
    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
    • Using the Leica ALS-50 Light Detection and Ranging (LiDAR) system, flight lines were planned for standard density 1.4 meter GSD. The Flight plan for the project includes the following specifications to fully meet the project requirements - single pass density of approximately 1.4 square meters per sample * Swath width ~688 meters * Flight altitude 1200 meters * flight line spacing ~516 meters with ~125 meters overlap *Scan Frequency- 36 Hz *Scan Angle- 16 degrees * Aircraft ground speed -- 120 knots * System Calibration pre and post mission * Two GPS base stations within 30 KM. Multiple returns were recorded for each laser pulse along with an intensity value for each return. The data are calibrated for geographic referencing. Points are further processed, using TerraSolid software, to classify return values. The first and last return data is filtered to remove the vegetation and above ground manmade features to yield a ground surface.
    • 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 19N (NAD83) coordinates and were vertically referenced to NAVD88 using the Geoid03 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 Geoid03. 2. The topographic las files were converted from a Projected Coordinate System (UTm 19N) to a Geographic Coordinate system (GCS). 3. The topographic las files' horizontal units were converted from meters to decimal degrees. 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: 2013-05-17

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