Orthoimagery of the coast of Alaska from Icy Cape to Cape Prince of Wales, 2016

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Frequently anticipated questions:

What does this data set describe?

Title:
Orthoimagery of the coast of Alaska from Icy Cape to Cape Prince of Wales, 2016
Abstract:
This part of the data release presents orthoimagery spanning the ocean shoreline of Alaska from Icy Cape to Cape Prince of Wales. Aerial images were collected, and data were processed, by Fairbanks Fodar (https://www.fairbanksfodar.com) in Fairbanks, Alaska, for the U.S. Geological Survey. The aerial images, from which the orthoimages were created, were collected in 2016 between August 29 and September 4 and extend from the shoreline to 400-4000 meters inland. The aerial images were collected with precise Global Positioning System (GPS) navigation data from a manned aircraft and were then processed into orthoimages photogrammetrically and using structure-from-motion (SFM) processing methods as described in Nolan and others, 2015. Orthoimages contain 4-band, 8-bit, unsigned raster data and are available in GeoTIFF format with 10, 16, or 20 cm cell sizes, depending on location. The orthoimages were converted to cloud optimized GeoTIFF format by the USGS. Due to file size and number limitations, the orthoimages have been divided into three groups by geographic location. Users are encouraged to use the Tile Index shapefile, which is also available in this data release, to identify orthoimagery files that are appropriate to a specific area of interest.
Supplemental_Information:
The Tile Index shapefile, also available in this data release, provides an outline of the data in each orthoimagery and elevation data file as well as the name of the file. Once the appropriate filenames are identified, users can either download files to their local server or stream the Cloud Optimized GeoTIFF (COG) directly to any COG supporting GIS. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in Esri format, this metadata file may include some Esri-specific terminology.
  1. How might this data set be cited?
    Nolan, Matt, Gibbs, Ann E., and Snyder, Alexander G., 20221115, Orthoimagery of the coast of Alaska from Icy Cape to Cape Prince of Wales, 2016: data release DOI:10.5066/P9PGJNE9, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Nolan, Matt, Gibbs, Ann E., and Snyder, Alexander G., 2022, Alaska coastal orthoimagery and elevation data: Icy Cape to Cape Prince of Wales, 2016: data release DOI:10.5066/P9PGJNE9, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    Other_Citation_Details:
    suggested citation: Nolan, M., Gibbs, A.E., and Snyder, A.G., 2022, Alaska coastal orthoimagery and elevation data: Icy Cape to Cape Prince of Wales, 2016: U.S. Geological Survey data release, https://doi.org/10.5066/P9PGJNE9.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -167.62629
    East_Bounding_Coordinate: -159.92483
    North_Bounding_Coordinate: 70.29046
    South_Bounding_Coordinate: 65.763323
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/62819e47d34e3bef0c9a3b0d?name=Orthoimagery_Example.jpg&allowOpen=true (JPEG)
    Graphic depicts an example of the orthoimagery data available in this release.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 29-Aug-2016
    Ending_Date: 04-Sep-2016
    Currentness_Reference:
    ground condition at time data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster digital data (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. 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: 3
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -165.000000
      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 0.20
      Ordinates (y-coordinates) are specified to the nearest 0.20
      Planar coordinates are specified in meters
      The horizontal datum used is NAD83_National_Spatial_Reference_System_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 1/298.257222101.
  7. How does the data set describe geographic features?
    Four-band GeoTIFF Rasters
    Pixel based 4-band, 8-bit, unsigned integer raster matrix with 4 layers of information for each pixel: Red, Green, Blue, and a data/no data indicator. (Source: Producer defined)
    Band_1
    Red wavelength band (Source: Producer defined)
    Range of values
    Minimum:0
    Maximum:255
    Band_2
    Green wavelength band (Source: Producer defined)
    Range of values
    Minimum:0
    Maximum:255
    Band_1
    Blue wavelength band (Source: Producer defined)
    Range of values
    Minimum:0
    Maximum:255
    Band_4
    Values indicating the presence (255) or absence (0) of RGB data from Bands 1,2, or 3. (Source: Producer defined)
    Range of values
    Minimum:0
    Maximum:255
    Entity_and_Attribute_Overview:
    These attribute values represent all orthoimagery rasters in this data release. Filenames are a unique identifier that describes certain attributes of the file, including the region, processing group, data type, grid size, and format. For example, the filename ‘shish_C_ortho_20cm-0-4x_cog’ refers to data that is somewhat close to the town of Shishmaref (‘shish’), processed with other files in group ‘C’, contains orthoimagery (‘ortho’) data, represented as a raster with cell size ‘20cm’, uniquely identified as ‘4-2, and stored as a Cloud Optimized GeoTIFF (‘cog’).
    Entity_and_Attribute_Detail_Citation: Producer defined

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Matt Nolan
    • Ann E. Gibbs
    • Alexander G. Snyder
  2. Who also contributed to the data set?
    Data collection was funded by the U.S. Geological Survey. Data acquisition and processing were conducted by Fairbanks Fodar.
  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

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

Why was the data set created?

Fairbanks Fodar was contracted by the USGS to acquire aerial photography and to generate structure-from-motion products including orthoimagery, digital elevation models, and elevation point clouds. USGS researchers use the orthorectified imagery to delineate shoreline position and characterize coastal geomorphology.

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: 04-Sep-2016 (process 1 of 3)
    Photographs were collected using a Nikon D800E with 24 mm lens mounted to a vertical camera port and connected to a survey grade GPS (Trimble 5700), which records an event marker for each photo, allowing for positional accuracy of less than 10 cm. The camera and GPS system was fit to a Cessna 170B, from which the photos were collected (Nolan and others, 2015). Photographs were primarily collected by flying two passes parallel to the shoreline in a flight pattern that achieved approximately 60 percent side lap and 80 percent end lap between photographs. Acquisition methods followed those outlined in Nolan and others (2015), with the exception of the number of passes made by the aircraft, which in this case was two instead of four. Person who carried out this activity:
    Dr. Matt Nolan
    Fairbanks Fodar
    Owner
    PO Box 82416
    Fairbanks, AK

    907-978-0542 (voice)
    info@fairbanksfodar.com
    Date: 04-Sep-2016 (process 2 of 3)
    Photographs were processed to optimize exposure and contrast. Photograph position GPS data were post-processed using precise point positioning (PPP) due to the absence of a nearby available GPS base station network. The overlapping aerial photos and GPS positions were input into Agisoft Photoscan Structure-from-Motion software. Data were processed in blocks, based in part on the time the imagery was collected. Agisoft generated point clouds, digital elevation models (DEMs), and orthoimagery, which were output in smaller blocks to make the data more manageable. More information about the processing steps used to generate this dataset are described in Nolan and other, 2015. Person who carried out this activity:
    Dr. Matt Nolan
    Fairbanks Fodar
    Owner
    PO Box 82416
    Fairbanks, AK

    907-978-0542 (voice)
    info@fairbanksfodar.com
    Date: 18-Jan-2022 (process 3 of 3)
    GDAL v3.3.1 (accessed February, 2022; https://gdal.org) was used to convert the orthoimagery to cloud optimized GeoTIFFs for data publication. The following command was used: gdal_translate ‘infile’ -of COG -stats -co BLOCKSIZE=256 -co COMPRESS=DEFLATE -co PREDICTOR=YES -co NUM_THREADS=ALL_CPUS -co BIGTIFF=YES. Person who carried out this activity:
    Alexander Snyder
    U.S. Geological Survey
    Oceanographer
    2885 Mission Street
    Santa Cruz, CA

    831-427-4450 (voice)
    agsnyder@usgs.gov
  3. What similar or related data should the user be aware of?
    Nolan, M., Larsen, C., and Sturm, M., 2015, Mapping snow depth from manned aircraft on landscape scales at centimeter resolution using structure-from-motion photogrammetry.

    Online Links:

    Other_Citation_Details:
    Nolan, M., Larsen, C., and Sturm, M., 2015, Mapping snow depth from manned aircraft on landscape scales at centimeter resolution using structure-from-motion photogrammetry: The Cryosphere, v. 9, p. 1445–1463, https://doi.org/10.5194/tc-9-1445-2015.
    Snyder, Alexander G., and Gibbs, Ann E., 2019, National assessment of shoreline change: A GIS compilation of vector shorelines and associated shoreline change data for the north coast of Alaska, Icy Cape to Cape Prince of Wales.

    Online Links:

    Other_Citation_Details:
    Snyder, A.G., and Gibbs, A.E., 2019, National assessment of shoreline change: A GIS compilation of updated vector shorelines and associated shoreline change data for the north coast of Alaska, Icy Cape to Cape Prince of Wales: U.S. Geological Survey data release, https://doi.org/10.5066/P9H1S1PV.
    Gibbs, Ann E., Snyder, Alexander G., and Richmond, Bruce M., 2019, National Assessment of Shoreline Change—Historical Shoreline Change Along the North Coast of Alaska, Icy Cape to Cape Prince of Wales.

    Online Links:

    Other_Citation_Details:
    Gibbs, A.E., Snyder, A.G., and Richmond, B.M., 2019, National assessment of shoreline change—Historical shoreline change along the north coast of Alaska, Icy Cape to Cape Prince of Wales: U.S. Geological Survey Open-File Report 2019–1146, 52 p., https://doi.org/10.3133/ofr20191146.
    Overbeck, Jacquelyn R., Buzard, Richard M., Turner, Mark M., Miller, Katie Y., and Glenn, Roberta J.T., 2020, Shoreline change at Alaska coastal communities: Alaska Division of Geological & Geophysical Surveys Report of Investigation.

    Online Links:

    Other_Citation_Details:
    Overbeck, J.R., Buzard, R.M., Turner, M.M., Miller, K.Y., and Glenn, R.J., 2020, Shoreline change at Alaska coastal communities: Alaska Division of Geological & Geophysical Surveys Report of Investigation 2020-10, 29 p., 47 sheets, https://doi.org/10.14509/30552.
    Quantum Spatial, Incorporated (QSI), 2019, Fairbanks Fodar Assessment.

    Other_Citation_Details:
    A formal evaluation performed by Quantum Spatial (2019) compared these data to vertical control points (see the Attribute Accuracy Report). Additional information about this report can be obtained by contact Ann Gibbs (agibbs@usgs.gov).

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

  1. How well have the observations been checked?
    A formal accuracy evaluation performed by Quantum Spatial, Incorporated (QSI; 2019) compared these data to other data sources. Additional information about this report can be obtained by contacting Ann Gibbs (agibbs@usgs.gov).
  2. How accurate are the geographic locations?
    Formal horizontal accuracy checks were not possible, but visual evaluations conducted by Quantum Spatial, Incorporated (QSI; 2019) confirmed that these data align well with other orthoimagery and lidar data. Gibbs and others (2019) used a horizontal uncertainty value of 0.3 meters.
  3. How accurate are the heights or depths?
    Not applicable.
  4. Where are the gaps in the data? What is missing?
    Structure-from-motion photogrammetry utilizes overlapping photographs, which can cause moving water surfaces to appear unrealistic. In some rare cases, images of water surface may appear in spatially unrealistic places. These artifacts are generally very recognizable. Users are advised to become familiar with the entire metadata document.
  5. How consistent are the relationships among the observations, including topology?
    Quantum Spatial, Incorporated (QSI; 2019) compared orthoimagery in this dataset to orthoimagery from other sources that cover the same area and the data in release were found to be very consistent in their visual and spatial representation of geomorphic features and infrastructure, except near areas of moving water. Data also include returns from vegetation/the canopy. Shallow underwater reconstructions have not been corrected for parallax.

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? These data are available in cloud optimized GeoTIFF format and include CSDGM FGDC compliant metadata.
  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?
  5. What hardware or software do I need in order to use the data set?
    These data can be viewed with Geographic Information Systems (GIS) software or other software capable of displaying geospatial raster data.

Who wrote the metadata?

Dates:
Last modified: 15-Nov-2022
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA

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_P9PGJNE9/Orthoimagery_metadata.faq.html>
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