ASIS2015_HRJQ_BE_z18_n88g12B_mosaic_metadata: Lidar-Derived Bare-Earth Digital Elevation Model (DEM) Mosaic for Coastal Topography—Assateague Island, Maryland and Virginia, Post-Hurricane Joaquin, 26 November 2015

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Frequently anticipated questions:

What does this data set describe?

Title:
ASIS2015_HRJQ_BE_z18_n88g12B_mosaic_metadata: Lidar-Derived Bare-Earth Digital Elevation Model (DEM) Mosaic for Coastal Topography—Assateague Island, Maryland and Virginia, Post-Hurricane Joaquin, 26 November 2015
Abstract:
A digital elevation model (DEM) mosaic was produced for Assateague Island, Maryland and Virginia, post-Hurricane Joaquin, from remotely sensed, geographically referenced elevation measurements collected by Quantum Spatial using a Leica ALS70 (1064-nm wavelength) lidar sensor.
Supplemental_Information:
Processed data products are used by the U.S. Geological Survey CMGP's National Assessment of Coastal Change Hazards project to quantify the vulnerability of shorelines to coastal change hazards such as severe storms, sea-level rise, and shoreline erosion and retreat.
  1. How might this data set be cited?
    U.S. Geological Survey, 20160506, ASIS2015_HRJQ_BE_z18_n88g12B_mosaic_metadata: Lidar-Derived Bare-Earth Digital Elevation Model (DEM) Mosaic for Coastal Topography—Assateague Island, Maryland and Virginia, Post-Hurricane Joaquin, 26 November 2015: U.S. Geological Survey Data Release doi:10.5066/F70P0X4G, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -75.4177
    East_Bounding_Coordinate: -75.0739
    North_Bounding_Coordinate: 38.3396
    South_Bounding_Coordinate: 37.8387
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 26-Nov-2015
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      Indirect_Spatial_Reference: Tiling Index
      This is a Raster data set. It contains the following raster data types:
      • Dimensions, type Pixel
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 18
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -75.000000
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000.000000
      False_Northing: 0
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 1.00000
      Ordinates (y-coordinates) are specified to the nearest 1.00000
      Planar coordinates are specified in meters
      The horizontal datum used is North American Datum of 1983 (2011).
      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 1/298.25722210100002.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988 (GEOID12B)
      Altitude_Resolution: 0.15
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      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?
    Acknowledgment of the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, as a data source would be appreciated in products developed from these data, and such acknowledgment as is standard for citation and legal practices for data source is expected. Sharing of new data layers developed directly from these data would also be appreciated by the U.S. Geological Survey staff. Users should be aware that comparisons with other datasets for the same area from other periods may be inaccurate because of inconsistencies resulting from changes in photointerpretation, mapping conventions, and digital processes over time. These data are not legal documents and are not to be used as such.
  3. To whom should users address questions about the data?
    Xan Fredericks
    Cherokee Nation Technologies, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
    Lidar Validation and Processing Analyst
    600 4th Street South
    St. Petersburg, FL
    USA

    727 502-8086 (voice)
    727 502-8182 (FAX)
    afredericks@usgs.gov

Why was the data set created?

The purpose of this project was to produce a highly detailed and accurate digital elevation map for Assateague Island, Maryland and Virginia for use as a management tool and to make these data available to natural-resource managers and research scientists. To ensure that SPCMSC data management protocols were followed, this survey was assigned a USGS field activity number (FAN), 2015-344-FA. Additional survey and data details are available at http://cmgds.marine.usgs.gov/fan_info.php?fan=2015-344-FA. USGS Contract: G10PC00026 Task Order Number: G16PD00038

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: 2015 (process 1 of 5)
    Bare-Earth Raster DEM Creation: Class 2 LiDAR was used to create a 1-meter Bare-Earth Raster DEM. Using automated scripting routines within ArcMap, an ERDAS Imagine .IMG file was created for each tile. Each surface was reviewed, using Global Mapper, to check for any surface anomalies or incorrect elevations found within the surface. Person who carried out this activity:
    Quantum Spatial
    523 Wellington Way
    Lexington, KY
    USA

    859-277-8700 (voice)
    859-277-8901 (FAX)
    Data sources produced in this process:
    • Bare-Earth Raster DEMs
    Date: 09-Mar-2016 (process 2 of 5)
    The provided DEM .IMG files were mosaicked using Global Mapper 16 (20160309) and exported as a GeoTIFF. Person who carried out this activity:
    Xan Fredericks
    Cherokee Nation Technologies, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
    Lidar Validation and Processing Analyst
    600 4th Street South
    St. Petersburg, FL
    USA

    727 502-8086 (voice)
    afredericks@usgs.gov
    Date: 04-Jan-2017 (process 3 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)
    aallwardt@usgs.gov
    Date: 07-Jun-2018 (process 4 of 5)
    Keywords section of metadata optimized by adding theme keyword thesauri and associated keywords; digitial object identifiers updated. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Arnell S. Forde
    Geologist
    600 4th Street South
    St. Petersburg, FL

    727-502-8000 (voice)
    aforde@usgs.gov
    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)
    vatnipp@usgs.gov
  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?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
    Quantum Spatial reports that the contract specifications required that only Nonvegetated Vertical Accuracy (NVA) were computed for raw lidar point cloud swath files. The vertical accuracy was tested with 13 independent surveys located in open terrain. These check points were not used in the calibration or post-processing of the lidar point cloud data. The survey check points were distributed throughout the project area. The independent check points were surveyed using the closed level loop technique. Elevations from the unclassified lidar surface were measured for the x,y location of each check point. Elevations interpolated from the lidar surface were then compared to the elevation values of the surveyed control. The RMSE was computed to be 0.042. AccuracyZ has been tested as 0.082 meters AccuracyZ at 95 percent Confidence Interval, meeting 19.6 cm NVA at 95 percent confidence level using (RMSEz * 1.9600) as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/American Society of Photogrammetry and Remote Sensing (ASPRS) Guidelines.
  4. Where are the gaps in the data? What is missing?
    These data cover Assateague Island, Maryland and Virginia.
  5. How consistent are the relationships among the observations, including topology?
    Quantum Spatial reports that data cover the entire area specified for this project. "NoData" values correspond with lack of bare-earth data within the survey bounds.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints None
Use_Constraints Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. The U.S. Geological Survey requests to be acknowledged as originator of these data in future products or derivative research.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    Attn: Xan Fredericks
    Lidar Validation and Processing Analyst, Cherokee Nation Technologies
    600 4th Street South
    St. Petersburg, FL
    USA

    727 502-8086 (voice)
  2. What's the catalog number I need to order this data set? ASIS2015_HRJQ_BE_z18_n88g12B_mosaic.tif
  3. What legal disclaimers am I supposed to read?
    Although these data have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The USGS shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 27-Sep-2023
Metadata author:
Xan Fredericks
Cherokee Nation Technology Solutions, U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
Lidar Validation and Processing Analyst
600 4th Street South
St. Petersburg, FL
USA

727 803-8747 (x3086) (voice)
afredericks@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/ASIS2015_HRJQ_BE_z18_n88g12B_mosaic_metadata.faq.html>
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