Digital surface models of the north coast of Barter Island, Alaska acquired on July 01 2014, September 07 2014, and July 05 2015 (GeoTIFF image)

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Frequently anticipated questions:

What does this data set describe?

Title:
Digital surface models of the north coast of Barter Island, Alaska acquired on July 01 2014, September 07 2014, and July 05 2015 (GeoTIFF image)
Abstract:
Digital surface elevation models (DSMs) of the coastline of Barter Island, Alaska derived from aerial photographs collected on July 01 2014, September 07 2014, and July 05 2015. Aerial photographs and coincident elevation data were processed using Structure-from-Motion (SfM) photogrammetric techniques. These files are single-band, 32-bit floating point DSMs (digital surface models) that represent surface elevations of buildings, vegetation, and uncovered ground surfaces in meters with 23 cm ground sample distance (GSD). The No Data value is set to -32767. The file employs Lempel-Ziv-Welch (LZW) compression.
  1. How might this data set be cited?
    Gibbs, Ann E., Snyder, Alexander G., and Nolan, Matt, 2019, Digital surface models of the north coast of Barter Island, Alaska acquired on July 01 2014, September 07 2014, and July 05 2015 (GeoTIFF image): data release DOI:10.5066/P9964TKX, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    Other_Citation_Details:
    The first Online Linkage link is to the publication landing page. The second link is to the page containing the data.
    This is part of the following larger work.

    Gibbs, Ann E., Nolan, Matt, and Snyder, Alexander G., 2019, Orthophotomosaics, elevation point clouds, digital surface elevation models and supporting data from the north coast of Barter Island, Alaska: data release DOI:10.5066/P9964TKX, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Gibbs, A.E., Nolan, M., and Snyder, A.G., 2019, Orthophotomosaics, elevation point clouds, digital surface elevation models, and supporting data from the north coast of Barter Island, Alaska: U.S. Geological Survey data release, https://doi.org/10.5066/P9964TKX.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -143.790570
    East_Bounding_Coordinate: -143.546318
    North_Bounding_Coordinate: 70.137845
    South_Bounding_Coordinate: 70.115080
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 01-Jul-2014
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: GeoTiff
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Raster data set.
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 7
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -141.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 0.23
      Ordinates (y-coordinates) are specified to the nearest 0.23
      Planar coordinates are specified in Meter
      The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    Elevation terrestrial
    DSMs provide elevation data in meters, in a single-band, 32-bit point raster data (file format-GeoTIFF) with 23-cm resolution. NoData values are -32767. The file employs Lempel-Ziv-Welch (LZW) compression. File format: GeoTIFF. (Source: U.S. Geological Survey (USGS) and Fairbanks Fodar)
    Entity_and_Attribute_Overview:
    A GeoTIFF file provides elevation data, in meters, for each acquisition date.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey (USGS) and Fairbanks Fodar

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Ann E. Gibbs
    • Alexander G. Snyder
    • Matt Nolan
  2. Who also contributed to the data set?
    Acknowledgment of the USGS Coastal and Marine Hazards and Resources Program and Fairbanks Fodar as a data source would be appreciated in products developed from these data.
  3. To whom should users address questions about the data?
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Attn: PCMSC Science Data Coordinator
    2885 Mission Street
    Santa Cruz, CA
    United States

    831-427-4747 (voice)
    pcmsc_data@usgs.gov

Why was the data set created?

Orthophotomosaics and coincident elevation data were acquired for the purpose of evaluating coastal change along the coast of Barter Island, Alaska.

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: 2016 (process 1 of 5)
    Digital surface models were created from elevation point cloud data in LAS format using the natural neighbor algorithm and half-meter point-thinning method in ArcMap. Where the range of point cloud elevations within a 1-m search radius exceeded 1 meter, the maximum value was applied to the output grid cell. Where the range of elevation values were less than 1-meter, a simple average of the points within the 1-m search radius was calculated. Prior to DSM creation the elevation data was shifted and edited to remove spurious elevation values associated with moving water surfaces. Areas where snow and ice were present in the imagery, particularly July 2014, were masked from the final DSMs. See metadata for orthoimagery and LAS data in the accompanying data release and Gibbs and others (2019) for additional information.
    Date: 19-Nov-2019 (process 2 of 5)
    Spelling correction was made to a keyword. Person who carried out this activity:
    Susan A. Cochran
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    2885 Mission St.
    Santa Cruz, CA
    USA

    831-460-7545 (voice)
    scochran@usgs.gov
    Date: 01-Sep-2020 (process 3 of 5)
    Title correction was made to a keyword thesaurus. Person who carried out this activity:
    Susan A. Cochran
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    2885 Mission St.
    Santa Cruz, CA
    USA

    831-460-7545 (voice)
    scochran@usgs.gov
    Date: 19-Oct-2020 (process 4 of 5)
    Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. 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
    Date: 13-Oct-2021 (process 5 of 5)
    Performed minor edits to the metadata to correct typos. No data were changed Person who carried out this activity:
    U.S. Geological Survey
    Attn: Susan A. Cochran
    Geologist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7545 (voice)
    scochran@usgs.gov
  3. What similar or related data should the user be aware of?
    Nolan, M., Larsen, C.F., and Sturm, M., 2015, Mapping snow-depth from manned-aircraft on landscape scales at centimeter resolution using Structure-from-Motion photogrammetry: The Cryosphere Vol. 9, pp. 1445-1463.

    Online Links:

    Gibbs, A.E., Nolan, M., and Richmond, B.R., 2016, Evaluating changes to arctic coastal bluffs using repeat aerial photography and structure-from-motion elevation models: Proceedings from 2015 Coastal Sediments Conference CD-ROM; 14 pp.

    Online Links:

    American Society for Photogrammetry and Remote Sensing (ASPRS), 2015, ASPRS Accuracy Standards for Digital Geospatial Data: manual Edition 1, Version 1.0.

    Online Links:

    • doi: 10.14358/PERS.81.3.A1-A26

    Gibbs, Ann E., Nolan, Matt, Richmond, Bruce M., Snyder, Alexander G., and Erikson, Li H., 2019, Assessing patterns of annual change to permafrost bluffs along the North Slope coast of Alaska using high-resolution imagery and elevation models: Geomorphology TBD.

    Online Links:

    • TBD

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

  1. How well have the observations been checked?
    Accuracies were evaluated using ground surface coordinates collected by USGS using precision GPS surveying techniques in 2014 and 2016. Horizontal accuracy of the DSMs was determined by the accuracy assessment of the orthoimagery used to derive them. Vertical accuracy was determined from comparison of elevations both at fixed, photo-identifiable points and walking survey transects. Values reported are the mean residual between surveyed ground measurements and image/DSM derived values. See Nolan and others (2015), Gibbs and others (2016), and Gibbs and others (2019), for comprehensive discussion of the accuracy, error analysis, and known anomalies.
  2. How accurate are the geographic locations?
    Horizontal accuracy of the DSMs was determined by the accuracy assessment of the orthoimagery used to derive them. The horizontal radial root mean square error (RMSE; ASPRS, 2015) of the orthoimagery data sets are as follows: BTI_Ortho_20140701 = 19 cm, BTI_Ortho_20140907 = 11 cm, BTI_Ortho_20150705 = 8 cm. Horizontal error was found to be less than the resolution of the derived DSMs.
  3. How accurate are the heights or depths?
    Vertical accuracy of the DSMs was determined by the comparison between surveyed ground measurements collected at both fixed, photo-identifiable points and walking survey points. The vertical root mean square error (RMSE; ASPRS, 2015) of the DSM data sets based on 8 fixed points are as follows: BTI_DSM_20140701 = 11 cm, BTI_Ortho_20140907 = 9 cm, BTI_Ortho_20150705 = 11 cm. The vertical root mean square error (RMSE; ASPRS, 2015) of the DSM data sets based on all 11007 survey points are as follows: BTI_DSM_20140701 = 8 cm, BTI_DSM_20140907 = 12 cm, BTI_DSM_20150705 = 20 cm.
  4. Where are the gaps in the data? What is missing?
    This dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details
  5. How consistent are the relationships among the observations, including topology?
    Data quality has been assessed relative to ground elevations collected in September of 2014 and 2016.

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:
USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey and Fairbanks Fodar as the originator(s) of the dataset and in products derived from these data.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? A GeoTIFF file for each acquisition date containing the 32-bit floating point raster.
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (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.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 13-Oct-2021
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA
United States

831-427-4747 (voice)
pcmsc_data@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/DataReleases/ScienceBase/DR_P9964TKX/BTI_DSM_metadata.faq.html>
Generated by mp version 2.9.50 on Thu Oct 14 14:47:21 2021