Lidar-Derived Bare-Earth Digital Elevation Model (DEM) Mosaic for Coastal Topography—Fire Island, New York, 07 May 2012

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Frequently anticipated questions:

What does this data set describe?

Title:
Lidar-Derived Bare-Earth Digital Elevation Model (DEM) Mosaic for Coastal Topography—Fire Island, New York, 07 May 2012
Abstract:
A digital elevation model (DEM) mosaic was produced for Fire Island, New York, from remotely sensed, geographically referenced elevation measurements collected by Photo Science, Inc. using an Optech Gemini lidar sensor flown on a Cessna 206 aircraft
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, 2016, Lidar-Derived Bare-Earth Digital Elevation Model (DEM) Mosaic for Coastal Topography—Fire Island, New York, 07 May 2012: U.S. Geological Survey Data Release doi:10.5066/F7513WBW, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -73.32130073
    East_Bounding_Coordinate: -72.74971703
    North_Bounding_Coordinate: 40.78366308
    South_Bounding_Coordinate: 40.60638627
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 07-May-2012
    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 (2007).
      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 (GEOID09)
      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
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
    Cartographer/Lidar Coordinator
    600 4th Street South
    St. Petersburg, FL
    USA

    727 502-8086 (voice)
    727 502-8182 (FAX)
    afredericks@usgs.gov
    Hours_of_Service: M-F, 8:00-4:00 ET

Why was the data set created?

The purpose of this project was to produce a highly detailed and accurate digital elevation map for Fire Island, New York 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), 12CNT09. Additional survey and data details are available at http://cmgds.marine.usgs.gov/fan_info.php?fan=12CNT09. USGS Contract: G10PC00026 Task Order Number: G10PD00588

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: 2012 (process 1 of 4)
    Photo Science, Inc. reports that Applanix software was used in the post processing of the airborne GPS and inertial data that is critical to the positioning and orientation of the sensor during all flights. POSPac MMS provides the smoothed best estimate of trajectory (SBET) that is necessary for Optech's post processor to develop the point cloud from the LiDAR missions. The point cloud is the mathematical three dimensional collection of all returns from all laser pulses as determined from the aerial mission. At this point this data is ready for analysis, classification, and filtering to generate a bare earth surface model in which the above ground features are removed from the data set. The point cloud was manipulated within the Optech software; GeoCue, TerraScan, and TerraModeler software was used for the automated data classification, manual cleanup, and bare earth generation from this data. Project specific macros were used to classify the ground and to remove the side overlap between parallel flight lines. All data was manually reviewed and any remaining artifacts removed using functionality provided by TerraScan and TerraModeler. Using automated scripting routines within ArcMap, the ground (ASPRS Class 2) and bare water (USGS Class 14) were used to create the 1 meter DEM. Final DEM tiles were clipped to the project tile boundary to provide a seamless dataset. ERDAS IMG files were then created as the project deliverable. A manual QA review of the tiles was completed in ArcMap and Global Mapper to ensure full coverage with no gaps or slivers within the project area. Person who carried out this activity:
    Photo Science, Inc.
    523 Wellington Way
    Lexington, KY
    USA

    859-277-8700 (voice)
    859-277-8901 (FAX)
    Hours_of_Service: Monday through Friday 8:00 AM to 5:00 PM (Eastern Time)
    Data sources produced in this process:
    • Bare-Earth Raster DEMs
    Date: 08-Aug-2016 (process 2 of 4)
    The provided DEM .IMG files were mosaicked using Global Mapper 16 (20160808) and exported as a GeoTIFF. Person who carried out this activity:
    Xan Fredericks
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
    Cartographer/Lidar Coordinator
    600 4th Street South
    St. Petersburg, FL
    USA

    727 502-8086 (voice)
    afredericks@usgs.gov
    Hours_of_Service: M-F, 8:00-4:00 ET
    Date: 24-Jan-2017 (process 3 of 4)
    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: 13-Oct-2020 (process 4 of 4)
    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?
    Photo Science, Inc. reports that the Raster DEMs were tested for both vertical and horizontal accuracy and that all data are seamless from one tile to the next, without gaps or no data areas. They also report that the vertical unit of the data file is in decimal meters with 2-decimal point precision and that the reported RMSEz value of 0.041 was determined using the calibration control points, and not the Blind Control; and that the calibration control points are the same points that were used to remove any bias in the dataset before bare earth editing. The listed RMSEz value of 0.041 was calculated from the ground (ASPRS Class 2) data in the final Classified LAS file.
  4. Where are the gaps in the data? What is missing?
    These data cover Fire Island, New York.
  5. How consistent are the relationships among the observations, including topology?
    Photo Science, Inc. reports that data contain complete coverage of tiles and that "NoData" values, if present, correspond with values outside of the project area and are represented with a value of -9999.

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
    Cartographer/Lidar Coordinator
    600 4th Street South
    St. Petersburg, FL
    USA

    727 502-8086 (voice)
    Hours_of_Service: M-F, 8:00-4:00 ET
  2. What's the catalog number I need to order this data set? FIIS2012_BE_z18_n88g09_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?
  5. Is there some other way to get the data?
    Contact U.S. Geological Survey for details.

Who wrote the metadata?

Dates:
Last modified: 02-Nov-2020
Metadata author:
Xan Fredericks
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL
Cartographer/Lidar Coordinator
600 4th Street South
St. Petersburg, FL
USA

727 502-8086 (voice)
afredericks@usgs.gov
Hours_of_Service: M-F, 8:00-4:00 ET
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/FIIS2012_BE_z18_n88g09_mosaic_metadata.faq.html>
Generated by mp version 2.9.50 on Tue Sep 21 18:18:49 2021