Nearshore bathymetry at Point Barrow, Alaska, 2022

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  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?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   Nowacki, Daniel J., Johnson, Cordell, Logan, Joshua B., and Stevens, Andrew W., 20250709, Nearshore bathymetry at Point Barrow, Alaska, 2022: data release DOI: 10.5066/P15BS65X, Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Online Links:

   • https://doi.org/10.5066/P15BS65X

   Other_Citation_Details:

   Suggested citation: Nowacki, D.J., Johnson, C., Logan, J.B., Stevens, A.W., 2025, Nearshore bathymetry at Point Barrow, Alaska, 2022: U.S. Geological Survey data release, https://doi.org/10.5066/P15BS65X.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -156.498916
   East_Bounding_Coordinate: -156.428817
   North_Bounding_Coordinate: 71.396931
   South_Bounding_Coordinate: 71.380881
   

3. What does it look like?

   point_barrow_bathy_2022_browse.png (PNG)

   Satellite image overlain with bathymetry data points collected at Point Barrow, Alaska in July 2022

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 29-Jul-2022

   Ending_Date: 30-Jul-2022

   Currentness_Reference:

   ground condition at the time source data were collected

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: comma-delimited text
   

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. It contains the following vector data types (SDTS terminology):
      • Point (225311)
   2. What coordinate system is used to represent geographic features?
      

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:

      UTM_Zone_Number: 4
      Transverse_Mercator:

      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -159.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0
      

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.6096
      Ordinates (y-coordinates) are specified to the nearest 0.6096
      Planar coordinates are specified in meters
      The horizontal datum used is D NAD 1983 2011.
      The ellipsoid used is GRS 1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      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 (NAVD88) GEOID12B
      Altitude_Resolution: 0.01
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:

      Explicit elevation coordinate included with horizontal coordinates

7. How does the data set describe geographic features?

   bathymetry_point_barrow_2022.csv

   Comma-separated value file (Source: Producer Defined)

   x_meters_utmz4n

   X coordinate (easting) in meters NAD83(2011) / UTM zone 4N (EPSG: 6333) (Source: Producer Defined)

   Range of values
   Minimum:	589074.54
   Maximum:	591559.47
   Units:	meters
   Resolution:	0.01

   y_meters_utmz4n

   Y coordinate (northing) in meters NAD83(2011) / UTM zone 4N (EPSG: 6333) (Source: Producer Defined)

   Range of values
   Minimum:	7921915.89
   Maximum:	7923235.58
   Units:	meters
   Resolution:	0.01

   z_meters_navd88

   Orthometric height (elevation) in meters NAVD88 GEOID12B (Source: Producer Defined)

   Range of values
   Minimum:	-7.82
   Maximum:	0.39
   Units:	meters
   Resolution:	0.01

   Entity_and_Attribute_Overview:

   These metadata describe a comma-separated value (csv) file containing bathymetry data from Point Barrow, Alaska. The first line is a header line, and each subsequent line contains x and y coordinates in meters NAD83(2011) / UTM zone 4N (EPSG: 6333) and an orthometric height (elevation) in meters NAVD88 GEOID12B.

   Entity_and_Attribute_Detail_Citation: U.S. Geological Survey
   

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Daniel J. Nowacki
   • Cordell Johnson
   • Joshua B. Logan
   • Andrew W. Stevens
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   PCMSC Science Data Coordinator

   U.S. Geological Survey, Pacific Coastal and Marine Science Center

   2885 Mission Street

   Santa Cruz, CA
   

   831-427-4747 (voice)

   pcmsc_data@usgs.gov

Why was the data set created?

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: 29-Jul-2022 (process 1 of 3)

   Bathymetry data were collected between July 29 and 30, 2022, using single-beam sonar systems and global navigation satellite systems (GNSS) receivers mounted on a small vessel. Depths from the echosounders were computed using sound velocity profiles measured using a CTD during the survey. Positioning of the survey vessels was determined at 10 Hz using survey-grade GNSS receivers. Output from the GNSS receivers and sonar systems were combined in real time by a computer running HYPACK hydrographic survey software. Navigation information was displayed on a video monitor, allowing vessel operators to navigate along planned survey lines.

   Date: 29-Aug-2022 (process 2 of 3)

   Survey-grade positions of the vessels were achieved with a single-base station and differential post-processing. Positioning data from the GNSS receivers were post-processed using Waypoint Grafnav to apply differential corrections from the GNSS base station site BRW1 operated by the National Geodetic Survey with known horizontal and vertical coordinates relative to the North American Datum of 1983. Orthometric elevations relative to the NAVD88 vertical datum were computed using NGS Geoid18 offsets. Bathymetric data were merged with post-processed positioning data, speed of sound corrections were applied, and spurious soundings were removed using a custom Graphical User Interface (GUI) programmed with the computer program MATLAB. The final point data are projected in cartesian coordinates in NAD83(2011) / UTM zone 4N (EPSG: 6333).

   Date: 25-Jun-2025 (process 3 of 3)

   All available bathymetry data from the survey were compiled into a comma-delimited text file in MATLAB for distribution.

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?
   No formal attribute accuracy tests were conducted.
2. How accurate are the geographic locations?
   Horizontal positions of the survey vessel were post-processed to apply differential corrections obtained from the National Geodetic Survey Site BRW1, located approximately 17 km from the survey area. Manufacturer reported accuracy for the differentially corrected horizontal positions for the GNSS rover trajectories is 0.8 cm + 0.5 ppm, suggesting a horizontal accuracy of approximately 1.7 cm. Uncertainty in the horizontal positions associated with pitch and roll of the survey vessels is unknown.
3. How accurate are the heights or depths?
   Manufacturer reported accuracy for the differentially corrected vertical positions for the GNSS rover trajectories is 1.5 cm + 1 ppm. The GNSS base station was located roughly 17 km from the survey site, suggesting the vertical accuracy of survey vessel positions to be 3.2 cm relative to the base station coordinate. Additional manufacturer reported uncertainty in the bathymetric soundings is 1 cm + 0.1 percent of water depth. Maximum water depths surveyed on this mapping mission are approximately 8 m, yielding a maximum vertical uncertainty of the bathymetric soundings of 1.8 cm. Total combined uncertainty in the bathymetric elevations is derived by summing the uncertainties from the GNSS and echosounder in quadrature, yielding a total uncertainty of approximately 3.7 cm. Uncertainty in the vertical positions associated with pitch and roll of the survey vessels is unknown.
4. Where are the gaps in the data? What is missing?
   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?
   All data falls within expected ranges.

How can someone get a copy of the data set?

1. Who distributes the data set? (Distributor 1 of 1)
   
   U.S. Geological Survey - CMGDS

   2885 Mission Street

   Santa Cruz, CA
   

   831-427-4747 (voice)

   pcmsc_data@usgs.gov
2. What's the catalog number I need to order this data set?
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?
   • Availability in digital form:

     Data format:	comma-delimited text file in format Comma-delimited text (version MATLAB Version: 9.8.0.1396136 (R2020a)) text Size: 6.0
     Network links:	https://doi.org/10.5066/P15BS65X

   • Cost to order the data: None

5. What hardware or software do I need in order to use the data set?
   These data can be opened with any text viewer, spreadsheet editor, or geographic information systems (GIS) software.

Who wrote the metadata?

Dates:

Last modified: 09-Jul-2025

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)