Elevation point clouds 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:
Elevation point clouds of the coast of Alaska from Icy Cape to Cape Prince of Wales, 2016
Abstract:
This part of the data release presents georeferenced elevation point clouds 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 point clouds were derived, 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 using structure-from-motion (SFM) methods as described in Nolan and others, 2015. The included files contain georeferenced point cloud data in .laz format. The point clouds were converted to .laz format by the USGS. Users are encouraged to use the Tile Index shapefile, which is also available in this data release, to identify elevation point cloud 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, Elevation point clouds 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/6283d73fd34e3bef0c9a4553?name=PointCloud_Example.jpg&allowOpen=true (JPEG)
    Image depicts an example of the elevation point cloud data included in this data release, colored by elevation and superimposed on a hillshade generated by the digital elevation model data included in this data 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: point cloud data LAZ (LAS 1.2)
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point 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: 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.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988 Geoid 12B
      Altitude_Resolution: 0.001
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    Point Cloud
    Point cloud is in LAS version 1.2 and compressed using LASzip compression (version 3.2r9 c2 50000) and contains georeferenced 3-dimensional surface elevation data. Surface elevation refers to the highest surface visible from aerial imagery (for example, exposed ground, rooftops, tree canopy). (Source: Producer defined)
    Value
    Orthometric height relative to the North American Vertical Datum of 1988, Geoid12B. (Source: Producer defined)
    Range of values
    Minimum:-4978.600
    Maximum:755.740
    Entity_and_Attribute_Overview:
    These attribute values represent all point cloud files this data release. Filenames are a unique identifier that describes certain attributes of the file, including the region and processing group, if applicable. For example, the filename ‘deering_Chunk_3’ refers to data that is somewhat close to the town of Deering and processed with other files in group ‘3’.
    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 LLC.
  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 and elevation data 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: 16-Feb-2022 (process 3 of 3)
    Point clouds were converted from LAS to LAZ for data publication using LasTools version 220113. 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, Incorporated (QSI; 2019) compared these data to vertical control points and other data sources (see the Attribute Accuracy Report). Additional information about this report can be obtained by contacting 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 evaluation performed by Quantum Spatial, Incorporated (QSI; 2019) compared these data to vertical control points, 214 in total, which were limited to the villages between Cape Prince of Wales and Point Hope. The data were also compared to lidar collected in 2004. Control points were used to quantifiably evaluate the vertical accuracy of these data. The horizontal accuracy of these data could not be reliable quantified, though a visual assessment indicated that these data align with the 2004 lidar.
  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?
    Quantum Spatial, Incorporated (QSI; 2019) compared a subset of this dataset to vertical control points, 214 in total, which were limited to the villages between Cape Prince of Wales and Point Hope. Although this comparison was limited to a small subset of data, the full extent of this dataset was collected and processed using consistent methods, so it is reasonable to expect similar accuracy values throughout the dataset. The evaluation determined that these data were on average 28 cm lower than the elevation of the GCPs, with a RMSE of 38 cm. These accuracy values do not include elevation data collected over water, which should not be used.
  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. Images of water and anomalous elevation may appear in spatially unrealistic places. These artifacts were not removed from this data set, but are very recognizable, especially when combined with the related coincident orthoimagery data set. 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 elevation data in this dataset to elevation measurements from other sources that cover the same area and were found to be consistent 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 LAZ format and include CSDGM FGDC compliant metadata. All data use the horizontal and vertical coordinate reference systems NAD83(2011)/UTM Zone 3N and NAVD88 (m) using geoid 12B.
  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 point cloud 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/PointCloud_metadata.faq.html>
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