Bathymetry at entrance to Golovnin Lagoon, Alaska, 2024

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, Buzard, Richard M., Snyder, Alexander G., and Erikson, Li, 20250708, Bathymetry at entrance to Golovnin Lagoon, Alaska, 2024: data release DOI:10.5066/P13YIWKC, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Online Links:

   • https://doi.org/10.5066/P13YIWKC

   This is part of the following larger work.
   Erikson, Li, Gibbs, Ann E., Buzard, Richard M., Nowacki, Daniel J., Snyder, Alexander G., Engelstad, Anita C., Johnson, Cordell, Nereson, Alexander L., Over, Jin-Si R., Russel, Paul, and Lyons, Colin, 2025, In situ field data, Coastal Alaska, 2023 to 2025: data release DOI:10.5066/P13YIWKC, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Other_Citation_Details:

   Suggested Citation: Suggested Citation: Erikson L.H., Gibbs A.E., Buzard R.M., Nowacki D.J., Snyder A.G., Engelstad A.C., Johnson C., Nereson A.L., Over J.R., Russel, P., Lyons, C., 2025, In situ field data, Coastal Alaska 2023 to 2025: U.S. Geological Survey data release, https://doi.org/10.5066/P13YIWKC

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -163.08766
   East_Bounding_Coordinate: -162.99025
   North_Bounding_Coordinate: 64.54394
   South_Bounding_Coordinate: 64.52270
   

3. What does it look like?

   golovnin_lagoon_2024_bathy_browse.png (PNG)

   Satellite image overlain with bathymetry data points collected at the entrance to Golovnin Lagoon, Alaska in September 2024.

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

   Calendar_Date: 11-Sep-2024

   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: tabular digital data
   

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 (213752)
   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: 0.9996
      Longitude_of_Central_Meridian: -165.0
      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.
      
7. How does the data set describe geographic features?

   bathymetry_golovnin_lagoon_2024.csv

   Comma Separated Value (CSV) file containing data. (Source: Producer Defined)

   Longitude

   Longitude in decimal degrees, WGS 1984 (Source: Producer Defined)

   Range of values
   Minimum:	-163.0859978
   Maximum:	-162.9919697
   Units:	decimal degrees
   Resolution:	0.0000001

   Latitude

   Latitude in decimal degrees, WGS 1984 (Source: Producer Defined)

   Range of values
   Minimum:	64.5229975
   Maximum:	64.5437963
   Units:	decimal degrees
   Resolution:	0.0000001

   Easting_m_UTM

   X coordinate (easting) in meters NAD83(2011) / UTM zone 3N (EPSG: 6332) (Source: Producer Defined)

   Range of values
   Minimum:	591785.48
   Maximum:	596363.12
   Units:	meters
   Resolution:	0.01

   Northing_m_UTM

   Y coordinate (northing) in meters NAD83(2011) / UTM zone 3N (EPSG: 6332) (Source: Producer Defined)

   Range of values
   Minimum:	7156801.94
   Maximum:	7158997.85
   Units:	meters
   Resolution:	0.01

   UTM_Zone

   UTM Zone in NAD83(2011) / UTM zone 3N (EPSG: 6332) (Source: Producer Defined)

   Value	Definition
   3N	UTM Zone 3 North

   Elevation_m_NAVD88

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

   Range of values
   Minimum:	-13.41
   Maximum:	0.25
   Units:	meters
   Resolution:	0.01

   Entity_and_Attribute_Overview:

   These metadata describe a comma-separated value (csv) file containing bathymetry data from the entrance to Golovnin Lagoon, Alaska. The first line is a header line and each subsequent line contains x and y coordinates in meters NAD83(2011) / UTM zone 3N (EPSG: 6332) 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
   • Richard M. Buzard
   • Alexander G. Snyder
   • Li Erikson
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: 11-Sep-2024 (process 1 of 3)

   Bathymetric data were collected using a single-beam sonar system and global navigation satellite system (GNSS) receiver mounted on a small boat. The sonar systems consisted of a CEE Hydrosystems CeeScope single-beam echosounder and 200 kHz transducer with a 9-degree beam angle. Depths from the echosounders were computed using sound velocity profiles measured using a YSI CastAway CTD during the survey. Positioning of the survey vessels was determined at 10 Hz using survey-grade GNSS receivers. Small boat operator to surveyed lines at speeds of 2 to 3 meters per second.

   Date: 20-Oct-2024 (process 2 of 3)

   Positions of the survey platforms were post-processed using a single-base station and differential post-processing. The position of the GNSS base station was derived from two static GNSS occupations from September 10 and 11, 2024, with durations of approximately 11 and 12 hours, respectively. The static observations were processed using the National Geodetic Survey Online Positioning User Service (OPUS) and averaged to derive the final base station coordinates relative to the North American Datum of 1983 (2011 realization). Positioning data from the GNSS receiver on the vessel was post-processed using Waypoint Grafnav to apply differential corrections from the GNSS base station. Orthometric elevations relative to the NAVD88 vertical datum were computed using National Geodetic Survey GEOID12A offsets. Bathymetric data were merged with post-processed positioning data and spurious soundings were removed using a custom Graphical User Interface (GUI) programmed with the computer program MATLAB. The final point data from the PWCs are projected in Cartesian coordinates using the UTM Zone 3 North, meters coordinate system.

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

   All available bathymetry data from the survey were compiled into a comma-delimited text file 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?
   Survey-grade positions of the small boat were achieved with global navigation satellite system (GNSS) receivers and a single GNSS base station. The position of the GNSS base station was derived from two static GNSS occupations from July 10 and 11, 2024, with durations of approximately 11 and 12 hours, respectively. The static observations were processed using the National Geodetic Survey Online Positioning User Service (OPUS) and averaged to derive the final base station coordinates relative to the North American Datum of 1983 (2011 realization). Positioning data from the survey vessels were post-processed using Waypoint Grafnav to apply differential corrections from the GNSS base station. Manufacturer reported accuracy for the differentially corrected horizontal positions for the GNSS rover trajectories is 0.8 cm plus 1 ppm. Baselines from the GNSS base station varied between 0.4 km and 2.8 km, suggesting the average horizontal accuracy of survey vessel position to be about 3.6 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?
   Uncertainty in the final elevations is derived from the combination of uncertainty in the GNSS positioning and bathymetric sounding measurements. Manufacturer reported accuracy for the differentially corrected vertical positions for the GNSS rover trajectories is 1.5 cm plus 1 ppm relative to the benchmark elevation, combined with the vertical accuracy of the NGS OPUS-derived position of the GNSS base station. Baselines from the GNSS base station reached 2.8 km, suggesting the vertical accuracy of survey vessel GNSS height relative to the ellipsoid to be 1.8 cm. However, the Geoid12b error in this region is 0.352 meters, bringing the orthometric (NAVD88) vertical accuracy to 0.354 m. The manufacturer of the single-beam echosounder used in this study reports a vertical accuracy of 1 cm. Additional uncertainty in the final computed elevations data is related to unmeasured variability in the speed of sound used to compute depths from bathymetric soundings and, thus, is depth-dependent. Based on analysis of available speed of sound measurements, we estimate uncertainties in the final depth soundings to be no greater than 1 percent of the water depth. The total vertical uncertainty is calculated using the constant- and depth-dependent factors summed in quadrature. Due to the relatively large error in the Geoid12b model, the final orthometric elevations range from 35.4 cm to 37.7 cm, with an average of 35.6cm. However, when working within geoid 12b, we recommend using the vertical accuracy values relative to the to the ellipsoid, which range from 2.1 cm to 13.1 cm, with an average of 7.6 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?
   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.

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? These data are available in a comma-separated value format (csv) accompanied by 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?
   • Availability in digital form:

     Data format:	comma-delimited text file in format Comma-delimited text (version Microsoft Excel (version 2408 (Build 17928.20538 Click-to-Run))) Size: 11.3
     Network links:	https://doi.org/10.5066/P13YIWKC

   • 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: 08-Jul-2025

Metadata author:

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

Metadata standard:

Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)