EAARL Topography-Gulf Islands National Seashore-Mississippi

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What does this data set describe?

Title: EAARL Topography-Gulf Islands National Seashore-Mississippi
Abstract: Elevation maps (also known as Digital Elevation Models or DEMs) of Gulf Islands National Seashore were produced from remotely-sensed, geographically-referenced elevation measurements in cooperation with NASA and NPS. Point data in ascii text files were interpolated in a GIS to create a grid or digital elevation model (DEM) of each beach surface. Elevation measurements were collected in Florida, Mississippi and Texas, over Gulf Islands National Seashore, using the NASA Experimental Advanced Airborne Research Lidar (EAARL), a pulsed laser ranging system mounted onboard an aircraft to measure ground elevation and coastal topography. The system uses high frequency laser beams directed at the earth's surface through an opening in the bottom of the aircraft's fuselage. The laser system records the time difference between emission of the laser beam and the reception of the reflected laser signal in the aircraft. The plane travels over the beach at approximately 60 meters per second while surveying from the low-water line to the landward base of the sand dunes. The EAARL, developed by the National Aeronautics and Space Administration (NASA) located at Wallops Flight Facility in Virginia, measures ground elevation with a vertical resolution of 15 centimeters. A sampling rate of 3 kHz or higher results in an extremely dense spatial elevation data set. Over 100 kilometers of coastline can be easily surveyed within a 3- to 4-hour mission time period. The ability to sample large areas rapidly and accurately is especially useful in morphologically dynamic areas such as barrier beaches. Quick assessment of topographic change can be made following storms comparing measurements against baseline data. When subsequent elevation maps for an area are analyzed, they provide a useful tool to make management decisions regarding coastal development.
For more information on Lidar science and the Experimental Advanced Airborne Research Lidar (EAARL) system and surveys, see http://ngom.usgs.gov/dsp/overview/index.php and http://ngom.usgs.gov/dsp/tech/eaarl/index.php .
Raw Lidar data is not in a format that is generally usable by Park Service resource managers and scientists for scientific analysis. Converting dense Lidar elevation data into a readily usable format without loss of essential information requires specialized processing. The U. S. Geological Survey converts raw Lidar data into a GIS-compatible map product to be provided to Park Service GIS specialists, managers, and scientists. The primary tool used in the conversion process is Airborne Lidar Processing System (ALPS), a multitiered processing system developed by a USGS/NASA collaborative for the use of topographic Lidar in coastal change assessment. Specialized processing algorithms are used to convert raw waveform Lidar data acquired by the EAARL to georeferenced spot (x,y,z) returns for "first surface" and "bare earth" topography. These data are then converted to the NAD83 horizontal and NAVD88 vertical datum (using the Geoid 99 model). The final products are 2x2-km map tiles written out in a standard geotiff format with associated metadata information. These tiles are created for visual interpretation and regional quantitative analysis. Metadata files include the standard FGDC format.See the source Lidar GeoTIFF tile for more specific accuracy information.
  1. How might this data set be cited?
    U.S. Geological Survey, 2007, EAARL Topography-Gulf Islands National Seashore-Mississippi: Open File Report 2007-1377, U. S. Geological Survey, St. Petersburg, FL.

    Online Links:

    The U. S. Geological Survey, in cooperation with the National Park Service (NPS) and the National Aeronautics and Space Administration (NASA), is to provide the coastal management community with usable, useful digital elevation products. The USGS processes aircraft Lidar data (provided by NASA), develops software tools and algorithms to use and analyze the data and make products available to the coastal management community through a variety of media, including the internet, CD-ROMs, DVDs and data reports.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.313
    East_Bounding_Coordinate: -69.911
    North_Bounding_Coordinate: 42.156
    South_Bounding_Coordinate: 41.602
  3. What does it look like?
    http://pubs.usgs.gov/of/2007/1377/HTML/Images/MS_inset.jpg (JPG)
    EAARL Topography-Gulf Islands National Seashore-Mississippi
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 01-Sep-2005
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Vector data set.
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      UTM_Zone_Number: 16
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -87.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 1.000000
      Ordinates (y-coordinates) are specified to the nearest 1.000000
      Planar coordinates are specified in meters
      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.
      Altitude_Datum_Name: North American Vertical Datum of 1988
      Altitude_Resolution: .15
      Altitude_Distance_Units: meters
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • U.S. Geological Survey
  2. Who also contributed to the data set?
    The U. S. Geological Surveyy, FISC St. Petersburg office, would like to acknowledge NASA Goddard Space Flight Center for their cooperation and assistance in the development of the data. The USGS would also like to acknowledge National Park Service management and personnel at Gulf Islands National Seashore.
  3. To whom should users address questions about the data?
    U. S. Geological Survey, FISC St. Petersburg
    600 4th Street South
    St. Petersburg, FL

    727 803-8747 (voice)
    Hours_of_Service: 8:30-5:00 M-F EST
    Contact_Instructions: Call Survey for Details

Why was the data set created?

One goal of the Project is to produce highly detailed and accurate digital elevation maps (DEMs) of National Seashores and coastal parks for use as a management tool and to make these maps available to natural resource managers within the parks.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2007 (process 1 of 5)
    The Lidar GeoTIFF data was too coarse to create aesthetically pleasing contours. A Neighborhood Statistics operation was run on the Lidar GeoTIFF file in ArcMap. The settings for the Neighborhood Statistics operation were a 14x14 cell rectangle, using the mean as the statistic type and then output to a temporary raster grid. Person who carried out this activity:
    National Park Service South Florida/Caribbean Network
    Attn: Iris Wilson
    Research Assistant
    18001 Old Cutler Road
    Palmetto Bay, FL

    (305) 252-0347 (voice)
    Hours_of_Service: 8:30-5:00 M-F EST
    Date: 2007 (process 2 of 5)
    Contour lines were generated using the Contour operation in ArcMap. The temporary Neighborhood Statistics grid was used as the input surface and the contour interval was set to 1 (meter). This was output to a permanent shapefile. Person who carried out this activity:
    National Park Service South Florida/Caribbean Network
    Attn: Iris Wilson
    Research Assistant
    18001 Old Cutler Road
    Palmetto Bay, FL

    (305) 252-0347 (voice)
    Hours_of_Service: 8:30-5:00 M-F EST
    Date: 09-Oct-2076 (process 3 of 5)
    Metadata imported into ArcCatalog from XML file. Person who carried out this activity:
    U. S. Geological Surveyy, FISC St. Petersburg
    600 4th Street South
    St. Petersburg, FL

    727 803-8747 (voice)
    Hours_of_Service: 8:30-5:00 M-F EST
    Date: 24-Jan-2017 (process 4 of 5)
    Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    Date: 13-Oct-2020 (process 5 of 5)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    The expected accuracy of the measured variables is as follows: attitude within 0.07 degree, 3-cm nominal ranging accuracy, and verticle elevation accuracy of +/- 15cm (bare earth). Quality checks are built into the data-processing software.
  2. How accurate are the geographic locations?
    Raw elevation measurements have been determined to be within 1.5 meter horizontal accuracy. Processing steps (grid interpolation) may introduce additional error which has not been tested at the time of this publication.
  3. How accurate are the heights or depths?
    Elevations of the DEM are vertically consistent with the point elevation data, +/- 15cm.
  4. Where are the gaps in the data? What is missing?
    Contour lines break where there was no data (value of -100) in the original Lidar tiles.
  5. How consistent are the relationships among the observations, including topology?
    This layer was generated from an existing Lidar tile.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Any use of these data signifies a user's agreement to comprehension and compliance of the U. S. Geological Survey's Standard Disclaimer. Ensure all portions of metadata are read and clearly understood before using these data in order to protect both user and USGS interests. See section 6.3 Distribution Liability.
Although the U. S. Geological Survey is making these data sets available to others who may find the data of value, the U. S. Geological Survey does not warrant, endorse, or recommend the use of these data setse for any given purpose. The user assumes the entire risk related to the use of these data. These data sets are not for navigational purposes. The U. S. Geological Survey is providing these data "as is", and the U. S. Geological Survey disclaims any and all warranties, whether expressed or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose. In no event will the USGS be liable to you or to any third party for any direct, indirect, incidental, consequential, special, or exemplary damages or lost profits resulting from any use or misuse of these data.Acknowledgement of the U.S. Geological Survey, FISC St. Petersburg office, as a data source would be appreciated in products developed from these data, and such acknowledgement as is standard for citation and legal practices for data source is expected by users of this data. Sharing new data layers developed directly from these data would also be appreciated by the USGS staff. Users should be aware that comparisons with other data sets for the same area from other time periods may be inaccurate due to inconsistencies resulting from changes in photo interpretation, mapping conventions, and digital processes over time. These data are not legal documents and are not to be used as such.
  1. Who distributes the data set? (Distributor 1 of 1)
    United States Geological Survey, FISC St. Petersburg
    600 4th Street South
    St. Petersburg, FL

    727-803-8747 (voice)
    Hours_of_Service: 8:30-5:00 M-F EST
    Contact_Instructions: Call U. S. Geological Survey for Details
  2. What's the catalog number I need to order this data set?
  3. What legal disclaimers am I supposed to read?
    The U. S. Geological Survey gives no warranty, expressed or implied, as to the accuracy, reliability, or completeness of these data. It is strongly recommended that these data are directly acquired from a USGS server and not indirectly through other sources which may have changed the data in some way. Although these data have been processed successfully on a computer system at the U. S. Geological Survey, no warranty expressed or implied is made regarding the utility of the data on another system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data.
  4. How can I download or order the data?
  5. Is there some other way to get the data?
    Call USGS for Details

Who wrote the metadata?

Last modified: 09-Nov-2021
Metadata author:
United States Geological Survey, St. Petersburg Coastal and Marine Science Center
Attn: SPCMSC Data Management Group
600 4th Street South
St. Petersburg, Florida

727-502-8000 (voice)
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/of2007-1377metadata.faq.html>
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