Metadata: Identification_Information: Citation: Citation_Information: Originator: Richard M. Buzard Originator: Li H. Erikson Originator: Ann E. Gibbs Originator: Alexander G. Snyder Originator: Anita C. Engelstad Originator: Cordell Johnson Originator: Joshua B. Logan Originator: Alexander L. Nereson Originator: Daniel J. Nowacki Originator: Jin-Si R. Over Publication_Date: 20260313 Title: GNSS elevation data collected in 2024 and 2025 on beaches and areas relevant to flood hazard studies in Alaska communities (ver. 2.0, March 2026) Edition: 2.0 Geospatial_Data_Presentation_Form: comma-delimited text Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P13YIWKC 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/P13YIWKC Larger_Work_Citation: Citation_Information: Originator: Li H. Erikson Originator: Ann E. Gibbs Originator: Richard M. Buzard Originator: Daniel J. Nowacki Originator: Alexander G. Snyder Originator: Anita C. Engelstad Originator: Cordell Johnson Originator: Alexander L. Nereson Originator: Jin-Si R. Over Originator: Paul Russel Originator: Colin Lyons Publication_Date: 2025 Title: In situ field data, Coastal Alaska, 2023 to 2025 (ver. 2.0, March 2026) Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P13YIWKC Publication_Information: Publication_Place: Pacific Coastal and Marine Science Center, Santa Cruz, CA Publisher: U.S. Geological Survey Other_Citation_Details: 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 (ver. 2.0, March 2026): U.S. Geological Survey data release, https://doi.org/10.5066/P13YIWKC. Online_Linkage: https://doi.org/10.5066/P13YIWKC Description: Abstract: Elevation point data were collected in Deering, Golovin, Koyuk, Kotzebue, Shishmaref, Teller, and Unalakleet, Alaska between June 2024 and August 2025. Coastal elevation profiles were measured at previously established locations. Other data points are categorized as base station, bathymetry, benchmark, camera calibration data, community-based monitoring profile, drainage observation, flood staff, ground control point, miscellaneous, and water level. The elevation data were collected with real-time kinematic global navigation satellite system (RTK-GNSS) equipment. Data are available in a single CSV file per community. Purpose: This product was created to help advance coastal storm response and recovery in Alaskan coastal communities in the wake of the September 2022 extratropical Typhoon Merbok disaster. It is being used by the USGS to document existing conditions and support the development of dynamic flood models for more than 20 communities along the northwest coast of Alaska. This product is intended for reuse by scientists, managers, and the general public. Supplemental_Information: Additional information about the field activity or activities from which these data were derived is available online at: https://cmgds.marine.usgs.gov/fan_info.php?fan=2024-634-FA https://cmgds.marine.usgs.gov/fan_info.php?fan=2024-635-FA https://cmgds.marine.usgs.gov/fan_info.php?fan=2024-637-FA https://cmgds.marine.usgs.gov/fan_info.php?fan=2025-628-FA Work was funded by Title VII of Division N in the Consolidated Appropriations Act, 2023 (Public Law 117-328) to support direct recovery and rebuilding decisions in the wake of declared disasters related to hurricanes and typhoons in 2022. For more information on these efforts, see https://www.usgs.gov/supplemental-appropriations-for-disaster-recovery-activities/typhoon-merbok-coastal-community. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20240607 Ending_Date: 20250813 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: -166.369518 East_Bounding_Coordinate: -160.784959 North_Bounding_Coordinate: 66.904291 South_Bounding_Coordinate: 63.870529 Keywords: Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:1299e64a-5ee3-4dfa-ac28-f1eed1b89d3c Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) keywords Theme_Keyword: beach Theme_Keyword: shore Theme: Theme_Keyword_Thesaurus: Data Categories for Marine Planning Theme_Keyword: Bathymetry and Elevation Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: coastal processes Theme_Keyword: geomorphology Theme_Keyword: topography Theme_Keyword: geospatial datasets 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_Keyword: Typhoon Merbok Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: State of Alaska Place_Keyword: Unalakleet Place_Keyword: Koyuk Place_Keyword: Kotzebue Place_Keyword: Deering Place_Keyword: Golovin Place_Keyword: Shishmaref Place_Keyword: Teller Access_Constraints: No access constraints 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(s) of the dataset and in products derived from these data. 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 Browse_Graphic: Browse_Graphic_File_Name: GNSS_ElevationData_locations.png Browse_Graphic_File_Description: Satellite image showing the locations where elevation data were collected. Browse_Graphic_File_Type: PNG Native_Data_Set_Environment: Trimble Business Center, National Geodetic Survey Online Positioning User Service (https://geodesy.noaa.gov/OPUS/) Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: No formal accuracy assessment was performed. Logical_Consistency_Report: All data fall within expected ranges. Completeness_Report: Dataset is considered complete for the information presented, as described in the abstract. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Horizontal accuracies of the base stations are computed using the National Geodetic Survey Online Positioning User Service. Horizontal errors of remaining points are computed during post-processing. Horizontal errors of all points are listed in the CSVs and do not exceed 0.075 m. Point IDs 11536-11548 and 11755-13492 in the Shishmaref CSV were collected using a GNSS system mounted to a moving vessel near the shoreline. Reported elevations are of the sea surface at the time of collection. Motion from boat maneuvering, waves, and other factors likely increases horizontal position uncertainty by an unknown amount. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Vertical accuracies of the base stations are computed using the National Geodetic Survey Online Positioning User Service. Vertical errors of remaining points are computed during post-processing. Vertical errors of all points are listed in the CSVs and do not exceed 0.117 m. Point IDs 11536-11548 and 11755-13492 in the Shishmaref file were collected using a GNSS system mounted to a moving vessel near the shoreline; reported elevations are of the sea surface at the time of collection. Motion from boat maneuvering, waves, and other factors likely increases vertical position uncertainty by an unknown amount. Lineage: Process_Step: Process_Description: The topographic survey data were acquired using multi-constellation dual-frequency GNSS rovers operating in real-time kinematic (RTK) or post-processed kinematic (PPK) mode. For measuring discreet points (such as ground control points), the GNSS rover was placed on a fixed-height rod and set to occupy the point for the duration of the observation (typically 10 - 30 seconds). For continuous measurements, the rover was either mounted to a backpack (for foot-based surveys), or to a vehicle such as an ATV, and set to record measurements at a fixed interval (typically 1-second). Process_Date: 20250813 Process_Step: Process_Description: All measurements were referenced to a concurrently operating GNSS base station operating on a nearby benchmark. Reference coordinates for the benchmarks were derived using the average of multiple high-quality position solutions from the National Geodetic Survey (NGS) Online Positioning User Service (OPUS). Process_Date: 20250813 Process_Step: Process_Description: Post-processing of PPK rover measurements was conducted using the Trimble Business Center GNSS post-processing software. Process_Date: 20250913 Process_Step: Process_Description: Elevation data collected during USGS field activity 2025-628-FA from Shishmaref and Teller were added to the data release. The previous process steps were revised to provide additional details about data acquisition and processing. Process_Date: 20260211 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Alexander L. Nereson Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-460-7577 Contact_Electronic_Mail_Address: anereson@usgs.gov Spatial_Data_Organization_Information: Indirect_Spatial_Reference: Data were post-processed in the Universal Transverse Mercator (UTM) zones referenced to North American Datum of 1983 with National Adjustment of 2011 (NAD83 [2011]). Eastings and northings are relative to the local UTM zone. Latitude and longitude are in WGS 1984. Elevations reference the North American Vertical Datum of 1988 using corrections from GEOID12B for Alaska (NAVD 88 [GEOID12B]). 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: 11852 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.000001 Longitude_Resolution: 0.000001 Geographic_Coordinate_Units: Decimal degrees Geodetic_Model: Horizontal_Datum_Name: WGS_1984 Ellipsoid_Name: WGS_1984 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257223563 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: GNSS_ElevationData__YYYYMM.csv Entity_Type_Definition: Coastal elevation measurements Entity_Type_Definition_Source: Producer defined Attribute: Attribute_Label: Point_ID Attribute_Definition: Unique identifying name Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Unrepresentable_Domain: Automatically generated sequential numbers Attribute: Attribute_Label: Easting_m_UTM Attribute_Definition: Easting coordinate. For Golovin, Kotzebue, Shishmaref, and Teller: NAD83(2011)/UTM zone 3N (EPSG: 6332). For Unalakleet and Koyuk NAD83(2011)/UTM zone 4N (EPSG: 6333). Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 397530.834 Range_Domain_Maximum: 607283.332 Attribute_Units_of_Measure: Meters Attribute_Measurement_Resolution: 0.001 Attribute: Attribute_Label: Northing_m_UTM Attribute_Definition: Northing coordinate. For Golovin, Kotzebue, Shishmaref, and Teller: NAD83(2011)/UTM zone 3N (EPSG: 6332). For Unalakleet and Koyuk NAD83(2011)/UTM zone 4N (EPSG: 6333). Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 7083816.221 Range_Domain_Maximum: 7422775.023 Attribute_Units_of_Measure: Meters Attribute_Measurement_Resolution: 0.001 Attribute: Attribute_Label: UTM_Zone Attribute_Definition: UTM zone in which location is located Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: 3N Enumerated_Domain_Value_Definition: UTM zone 3N (EPSG: 6332) Enumerated_Domain_Value_Definition_Source: Producer defined Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: 4N Enumerated_Domain_Value_Definition: UTM zone 4N (EPSG: 6333) Enumerated_Domain_Value_Definition_Source: Producer defined Attribute: Attribute_Label: Elevation_m_NAVD88 Attribute_Definition: Elevation relative to NAVD88 (GEOID12B). A null or no data value of -9999.000 is used for records where elevation was not reliably measured due to undocumented antenna heights above the ground surface. Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.358 Range_Domain_Maximum: 51.886 Attribute_Units_of_Measure: Meters Attribute_Measurement_Resolution: 0.001 Attribute: Attribute_Label: Latitude Attribute_Definition: Latitude coordinate Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 63.870529 Range_Domain_Maximum: 66.904291 Attribute_Units_of_Measure: Decimal degrees Attribute_Measurement_Resolution: 0.000001 Attribute: Attribute_Label: Longitude Attribute_Definition: Longitude coordinate Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -166.369518 Range_Domain_Maximum: -160.784959 Attribute_Units_of_Measure: Decimal degrees Attribute_Measurement_Resolution: 0.000001 Attribute: Attribute_Label: Horizontal_Precision_m Attribute_Definition: Horizontal error Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.006 Range_Domain_Maximum: 0.075 Attribute_Units_of_Measure: Meters Attribute_Measurement_Resolution: 0.001 Attribute: Attribute_Label: Vertical_Precision_m Attribute_Definition: Vertical error. A null or no data value of -9999.000 is used for records where elevation was not reliably measured due to undocumented antenna heights above the ground surface. Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.003 Range_Domain_Maximum: 0.117 Attribute_Units_of_Measure: Meters Attribute_Measurement_Resolution: 0.001 Attribute: Attribute_Label: Datetime_UTC Attribute_Definition: Start date and time in UTC (month/day/year hour:minutes) Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 06/07/2024 03:44 Range_Domain_Maximum: 08/13/2025 06:05 Attribute_Units_of_Measure: MM/DD/YYYY hh:mm Attribute: Attribute_Label: Notes Attribute_Definition: Description of point Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Unrepresentable_Domain: Descriptive text. Missing information is marked by NAN (not a number) Attribute: Attribute_Label: Profile_Line Attribute_Definition: Coastal elevation profile number. Where not applicable, a fill value of -9999 is used Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 1 Range_Domain_Maximum: 102 Attribute_Units_of_Measure: dimensionless Attribute: Attribute_Label: Point_Category Attribute_Definition: Descriptive text of the point category Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Base station Enumerated_Domain_Value_Definition: the location of the GNSS-RTK survey base station Enumerated_Domain_Value_Definition_Source: Producer defined Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Benchmark Enumerated_Domain_Value_Definition: location of recovered benchmark Enumerated_Domain_Value_Definition_Source: Producer defined Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Camera calibration data Enumerated_Domain_Value_Definition: GNSS point taken to support calibration of camera system Enumerated_Domain_Value_Definition_Source: Producer defined Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Community based monitoring profile Enumerated_Domain_Value_Definition: an elevation profile used by the community for erosion monitoring that is not a designated profile in the Alaska Coastal Profile Tool Enumerated_Domain_Value_Definition_Source: Producer defined Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Drainage observation Enumerated_Domain_Value_Definition: GNSS point taken to support understanding of drainage, such as culverts, ditches, and bare earth elevation in dense vegetation Enumerated_Domain_Value_Definition_Source: Producer defined Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Flood staff Enumerated_Domain_Value_Definition: location of a USGS installed flood staff Enumerated_Domain_Value_Definition_Source: Producer defined Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Ground control point (GCP) Enumerated_Domain_Value_Definition: GNSS point taken as a control to support georeferencing Enumerated_Domain_Value_Definition_Source: Producer defined Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Miscellaneous Enumerated_Domain_Value_Definition: GNSS point taken that does not fit into any of these categories or may not be needed Enumerated_Domain_Value_Definition_Source: Producer defined Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Profile Enumerated_Domain_Value_Definition: GNSS point taken along a profile as numbered in the Alaska Coastal Profile Tool Enumerated_Domain_Value_Definition_Source: Producer defined Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Water level Enumerated_Domain_Value_Definition: GNSS point taken at a still water elevation at a specified time Enumerated_Domain_Value_Definition_Source: Producer defined Overview_Description: Entity_and_Attribute_Overview: The first line of the csv file is a header line. Entity_and_Attribute_Detail_Citation: U.S. Geological Survey Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey - CMGDS 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 Resource_Description: These data are available in csv format 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_Information_Content: CSV contains location and elevation data File_Decompression_Technique: No compression applied. Transfer_Size: 1.68 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://doi.org/10.5066/P13YIWKC Access_Instructions: Data can be downloaded using the Network_Resource_Name link then scrolling down to the Location-Elevation Data section. Fees: None. Technical_Prerequisites: The CSV data can be viewed with any text reading software. Metadata_Reference_Information: Metadata_Date: 20260313 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