Metadata: Identification_Information: Citation: Citation_Information: Originator: Alexander G. Snyder Originator: Cordell D. Johnson Originator: Ann E. Gibbs Originator: Li H. Erikson Publication_Date: 20210719 Title: Nearshore bathymetry data from the Unalakleet River mouth, Alaska, 2019 Geospatial_Data_Presentation_Form: comma-delimited text Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P9238F8K Publication_Information: Publication_Place: Pacific Coastal and Marine Science Center, Santa Cruz, California Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/P9238F8K Online_Linkage: https://www.sciencebase.gov/catalog/item/60c24fbad34e86b9389559b8 Description: Abstract: This data release presents nearshore bathymetry data collected at the mouth of the Unalakleet River in Alaska, near the city of Unalakleet. The data were collected in August 2019 by the U.S. Geological Survey, Pacific Coastal and Marine Science Center. Nearshore bathymetry was measured along survey lines from the shore to a depth of approximately -7.4 m NAVD88 and in a portion of the estuary closest to the mouth. Bathymetry data were collected using small boat equipped with a single-beam sonar system and global navigation satellite system (GNSS) receiver. The sonar system consisted of an Odom Echotrac CV-100 single-beam echosounder and 200 kHz transducer with a 9-degree beam. Depths from the seafloor to the echosounder were calculated using the digitized acoustic backscatter and sound velocity profiles, measured in multiple locations using a YSI CastAway CTD. The position of the boat and echosounder was recorded at 10 Hz using a Trimble R7 receiver and Zephyr 2 antenna. Survey-grade vertical and horizontal positions were achieved by applying differential corrections from a nearby GNSS base station installed for the purposes of this survey. Purpose: Data were collected to create a digital elevation model of the nearshore bathymetry for use in coastal flooding models. These data are intended for science researchers, students, policy makers, and the general public. These data can be used with geographic information systems or other software to identify shallow-water bathymetric features. Supplemental_Information: Additional information about the field activity from which these data were derived is available online at: https://cmgds.marine.usgs.gov/fan_info.php?fan=2019-629-FA 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. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20190709 Ending_Date: 20190712 Currentness_Reference: ground condition at time data were collected Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -160.863919 East_Bounding_Coordinate: -160.766694 North_Bounding_Coordinate: 63.881365 South_Bounding_Coordinate: 63.846674 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: elevation Theme: Theme_Keyword_Thesaurus: Data Categories for Marine Planning Theme_Keyword: Bathymetry and Elevation Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: bathymetry Theme_Keyword: bathymetry measurement Theme_Keyword: GPS measurement Theme: Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) keywords Theme_Keyword: single-beam echo sounder Theme_Keyword: Global Positioning System (GPS) observations Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Coastal and Marine Hazards and Resources Program Theme_Keyword: CMHRP Theme_Keyword: Pacific Coastal and Marine Science Center Theme_Keyword: PCMSC Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:60c24fbad34e86b9389559b8 Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: Norton Sound Place_Keyword: Pacific Ocean Place_Keyword: Unalakleet Place_Keyword: City of Unalakleet Place_Keyword: Unalakleet River Place_Keyword: State of Alaska Place_Keyword: Nome Census Area 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 as the originator of the dataset and in products derived from these data. This information is not intended for navigation purposes. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center Contact_Person: PCMSC Science Data Coordinator Contact_Address: Address_Type: mailing and physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-427-4747 Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov Native_Data_Set_Environment: MATLAB Version: 8.6.6.958874 (R2015b) Cross_Reference: Citation_Information: Originator: International Hydrographic Organization (IHO) Publication_Date: 2008 Title: IHO standards for hydrographic surveys (6th ed.) Online_Linkage: https://iho.int/uploads/user/pubs/Drafts/S-44_Edition_6.0.0-Final.pdf Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: No formal attribute accuracy tests were conducted. Logical_Consistency_Report: All data falls within expected ranges. Completeness_Report: 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. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: 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 four static GNSS occupations from July 7 to July 12, 2019, with durations ranging from 3 to 13 hours. 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 + 0.5 ppm. Baselines from the GNSS base station varied between 0.1 km and 4.5 km with a mean of 1 km, suggesting the average horizontal accuracy of survey vessel positions to be about 1 cm. Uncertainty in the horizontal positions associated with pitch and roll of the survey vessels is unknown. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: 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 + 1 ppm relative to the benchmark elevation. Baselines from the GNSS base station varied between 0.1 m and 4.5 km with a mean of 1 km, suggesting the average vertical accuracy of survey vessel positions to be about 2.5 cm. 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 (International Hydrographic Organization, 2008). The vertical uncertainty in final elevations varied between 3 cm and 8 cm with a mean vertical uncertainty of 4 cm. Uncertainty in the vertical positions associated with pitch and roll of the survey vessels is unknown. Lineage: Process_Step: Process_Description: Bathymetry data were collected between July 9 and July 12, 2019, using a single-beam sonar system and global navigation satellite system (GNSS) receiver mounted on a small boat. The sonar system consisted of an Odom Echotrac CV-100 single-beam echosounder and 200 kHz transducer with a 9-degree beam angle. Raw acoustic backscatter returns were digitized by the echosounder with a vertical resolution of 1.25 cm. Depths from the echosounder was computed using sound velocity profiles measured using a YSI CastAway CTD during the survey. Positioning of the survey vessel was determined at 10 Hz using survey-grade GNSS receiver. Output from the GNSS receiver and sonar system were combined in real time on the small boat by a computer running HYPACK hydrographic survey software. Navigation information was displayed on a computer monitor, allowing the boat operator to navigate along survey lines at speeds of 2 to 3 m/s. Process_Date: 20190712 Process_Step: Process_Description: Survey-grade positions were achieved with a single-base station and differential post-processing. The position of the GNSS base station was derived from four static GNSS occupations from July 7 to July 12, 2019, with durations ranging from 3 to 13 hours. 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 vessel’s GNSS receiver were 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 Geoid12b 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 survey vessel was projected in cartesian coordinates using the Universal Transverse Mercator Zone 4 North, meters coordinate system. Process_Date: 20200423 Process_Step: Process_Description: All available bathymetry data from the survey were compiled into a comma-delimited text file for distribution. Process_Date: 20210512 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Point Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Point_and_Vector_Object_Count: 895748 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.00000001 Longitude_Resolution: 0.00000001 Geographic_Coordinate_Units: Decimal Degrees Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983, 2011 realization Ellipsoid_Name: GRS_1980 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257222101 Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: North American Vertical Datum of 1988 Altitude_Resolution: 0.001 Altitude_Distance_Units: meters Altitude_Encoding_Method: Explicit elevation coordinate included with horizontal coordinates Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: Attribute Table Entity_Type_Definition: Table containing attribute information associated with the dataset. Entity_Type_Definition_Source: Producer defined Attribute: Attribute_Label: Survey_Date_Time Attribute_Definition: The date and time of data collection in Greenwich Mean Time (GMT). Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 2019-Jul-09 19:55:20.589 Range_Domain_Maximum: 2019-Jul-12 20:27:05.249 Attribute_Units_of_Measure: Date and time in yyyy-mmm-dd hh:mm:ss.fff format Attribute_Measurement_Resolution: 0.001 Attribute: Attribute_Label: Longitude Attribute_Definition: Longitude coordinate of data point relative to the North American Datum of 1983, 2011 realization Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -160.8639194 Range_Domain_Maximum: -160.7666941 Attribute_Units_of_Measure: Decimal degrees Attribute_Measurement_Resolution: 0.0000001 Attribute: Attribute_Label: Latitude Attribute_Definition: Latitude coordinate of data point relative to the North American Datum of 1983, 2011 realization Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 63.84667372 Range_Domain_Maximum: 63.88136471 Attribute_Units_of_Measure: Decimal degrees Attribute_Measurement_Resolution: 0.0000001 Attribute: Attribute_Label: Easting_m Attribute_Definition: Easting coordinate of data point relative to the North American Datum of 1983, 2011 realization, projected to the Universal Transverse Mercator, Zone 4. Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 408372.883 Range_Domain_Maximum: 413201.097 Attribute_Units_of_Measure: Meters Attribute_Measurement_Resolution: 0.001 Attribute: Attribute_Label: Northing_m Attribute_Definition: Northing coordinate of data point relative to the North American Datum of 1983, 2011 realization, projected to the Universal Transverse Mercator, Zone 4. Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 7081260.852 Range_Domain_Maximum: 7085018.336 Attribute_Units_of_Measure: Meters Attribute_Measurement_Resolution: 0.001 Attribute: Attribute_Label: Ellip_Ht_m Attribute_Definition: Height in meters of data point with reference to the reference ellipsoid. Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.324 Range_Domain_Maximum: 9.366 Attribute_Units_of_Measure: Meters Attribute_Measurement_Resolution: 0.001 Attribute: Attribute_Label: Ortho_Ht_m Attribute_Definition: Height in meters of data point with reference to the North American Vertical Datum of 1988. Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -7.416 Range_Domain_Maximum: 1.598 Attribute_Units_of_Measure: Meters Attribute_Measurement_Resolution: 0.001 Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey - ScienceBase Contact_Address: Address_Type: Mailing and Physical Address: Denver Federal Center, Building 810, Mail Stop 302 City: Denver State_or_Province: CO Postal_Code: 80225 Contact_Voice_Telephone: 1-888-275-8747 Contact_Electronic_Mail_Address: sciencebase@usgs.gov Resource_Description: Bathymetry data are available as a comma-delimited text file (unk19_july_bathymetry.csv), along with associated metadata. Distribution_Liability: 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. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: comma-delimited text Format_Version_Number: Matlab 8.6.0.958874 Format_Specification: text Format_Information_Content: comma-delimited text file Transfer_Size: 19.1 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://www.sciencebase.gov/catalog/file/get/60c24fbad34e86b9389559b8 Network_Resource_Name: https://doi.org/10.5066/P9238F8K Access_Instructions: Data can be downloaded using the Network_Resource_Name links. The first link is a direct link to download the zipped file of data and metadata. The second link points to a landing page for the entire data release. Fees: None. Metadata_Reference_Information: Metadata_Date: 20210719 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center Contact_Person: PCMSC Science Data Coordinator Contact_Address: Address_Type: mailing and physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-427-4747 Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998