Metadata: Identification_Information: Citation: Citation_Information: Originator: Rachel E. Henderson Originator: Amy S. Farris Publication_Date: 20231023 Title: Bias feature containing proxy-datum bias information to be used in the Digital Shoreline Analysis System for the western coast of North Carolina from Cape Fear to the South Carolina border (NCwest) Edition: 1.0 Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: data release Issue_Identification: doi:10.5066/P9HYNUNV Publication_Information: Publication_Place: Woods Hole Coastal and Marine Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Hazards and Resources Program Online_Linkage: https://doi.org/10.5066/P9HYNUNV Online_Linkage: https://www.sciencebase.gov/catalog/item/64de701cd34e5f6cd55350cf Larger_Work_Citation: Citation_Information: Originator: Marie K. Bartlett Originator: Amy S. Farris Originator: Kathryn M. Weber Originator: Rachel E. Henderson Publication_Date: 2023 Title: USGS National Shoreline Change — 2017 lidar-derived mean high water shoreline and associated shoreline change data for coastal North Carolina Edition: 1 Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: data release Issue_Identification: doi:10.5066/P9HYNUNV Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: Bartlett, M.K., Farris, A.S., Weber, K.M., and Henderson, R.E., 2023, USGS National Shoreline Change — 2017 lidar-derived mean high water shoreline and associated shoreline change data for coastal North Carolina: U.S. Geological Survey data release, https://doi.org/P9HYNUNV. Online_Linkage: https://doi.org/10.5066/P9HYNUNV Online_Linkage: https://www.sciencebase.gov/catalog/item/64de3810d34e5f6cd5533c78 Description: Abstract: The U.S. Geological Survey (USGS) has compiled national shoreline data for more than 20 years to document coastal change and serve the needs of research, management, and the public. Maintaining a record of historical shoreline positions is an effective method to monitor national shoreline evolution over time, enabling scientists to identify areas most susceptible to erosion or accretion. These data can help coastal managers and planners understand which areas of the coast are vulnerable to change. This data release includes one new mean high water (MHW) shoreline extracted from lidar data collected in 2017 for the entire coastal region of North Carolina which is divided into four subregions: northern North Carolina (NCnorth), central North Carolina (NCcentral), southern North Carolina (NCsouth), and western North Carolina (NCwest). Previously published historical shorelines for North Carolina (Kratzmann and others, 2017) were combined with the new lidar shoreline to calculate long-term (up to 169 years) and short-term (up to 20 years) rates of change. Files associated with the long-term and short-term rates are appended with "LT" and "ST", respectively. A proxy-datum bias reference line that accounts for the positional difference in a proxy shoreline (e.g. High Water Line (HWL) shoreline) and a datum shoreline (e.g. MHW shoreline) is also included in this release. Purpose: This dataset documents the proxy-datum bias (PDB) value and the uncertainty in the PDB. The "bias feature" is a shapefile representation the proxy-datum bias (PDB) data previously published in tabular format (Himmelstoss and others, 2010, Himmelstoss and others, 2018). These PDB data are used to shift older proxy-based shorelines so that they can be directly compared to newer datum-based shorelines and accurate rates can be calculated. Supplemental_Information: Cross-referenced citations are applicable to the dataset as a whole. Additional citations are located within individual process steps that pertain specifically to the method described in that step. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2018 Currentness_Reference: ground condition at the time of elevation source data Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -78.546844 East_Bounding_Coordinate: -78.011153 North_Bounding_Coordinate: 33.913617 South_Bounding_Coordinate: 33.849516 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: oceans Theme_Keyword: environment Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Coastal and Marine Hazards and Resources Program Theme_Keyword: CMHRP Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: National Oceanic and Atmospheric Administration Theme_Keyword: NOAA Theme_Keyword: Woods Hole Coastal and Marine Science Center Theme_Keyword: Coastal Services Center Theme_Keyword: CSC Theme_Keyword: USGS National Shoreline Change Project Theme_Keyword: Digital Shoreline Analysis System Theme_Keyword: DSAS Theme_Keyword: proxy-datum bias Theme_Keyword: PDB Theme_Keyword: mean high water Theme_Keyword: MHW Theme_Keyword: high water line Theme_Keyword: HWL Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: geospatial datasets Theme_Keyword: coastal processes Theme_Keyword: erosion Theme_Keyword: shoreline accretion Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:64de701cd34e5f6cd55350cf Place: Place_Keyword_Thesaurus: None Place_Keyword: United States Place_Keyword: Atlantic Coast Place_Keyword: North Carolina Access_Constraints: None Use_Constraints: These data were generated for use within the Digital Shoreline Analysis System (DSAS) v5.1 software, with shoreline data that has both mean high water (MHW) and high water line (HWL) data types present. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. These data should not be used for any purpose other than that for which they are intended. The United States Geological Survey does not guarantee its validity. Assumptions, analyses, opinions, and actual outcomes may vary. The user should always verify actual data and exercise their own professional judgment when interpreting any outcomes. Please recognize the U.S. Geological Survey as the originator of the dataset. These data are not to be used for navigation. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Rachel E. Henderson Contact_Address: Address_Type: mailing and physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: US Contact_Voice_Telephone: 508-548-8700 Contact_Facsimile_Telephone: 508-547-2310 Contact_Electronic_Mail_Address: rehenderson@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: https://www.sciencebase.gov/catalog/file/get/64de701cd34e5f6cd55350cf?name=NCwest_bias_feature_browse.png Browse_Graphic_File_Description: Map view of the bias dataset for the region. Browse_Graphic_File_Type: PNG Native_Data_Set_Environment: Microsoft Windows 10, Esri ArcGIS 10.7.1 Cross_Reference: Citation_Information: Originator: Cheryl J. Hapke Originator: Emily A. Himmelstoss Originator: Meredith G. Kratzmann Originator: Jeffrey List Originator: E. Robert Thieler Publication_Date: 20100101 Title: National Assessment of Shoreline Change: Historical Shoreline Change along the New England and Mid-Atlantic Coasts Geospatial_Data_Presentation_Form: publication Series_Information: Series_Name: open file report Issue_Identification: 2010-1118 Publication_Information: Publication_Place: Woods Hole Coastal and Marine Science Center, Woods Hole, MA Publisher: : U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: https://doi.org/10.3133/ofr20101118 Online_Linkage: http://pubs.usgs.gov/of/2010/1118/ Cross_Reference: Citation_Information: Originator: Meredith G. Kratzmann Originator: Emily A. Himmelstoss Originator: E. Robert Thieler Publication_Date: 2017 Title: National assessment of shoreline change – A GIS compilation of updated vector shorelines and associated shoreline change data for the Southeast Atlantic Coast Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: data release Issue_Identification: doi:10.5066/F74X55X7 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/F74X55X7 Cross_Reference: Citation_Information: Originator: Emily A. Himmelstoss Originator: Meredith G. Kratzmann Originator: E. Robert Thieler Publication_Date: 2017 Title: National assessment of shoreline change—Summary statistics for updated vector shorelines and associated shoreline change data for the Gulf of Mexico and Southeast Atlantic coasts Series_Information: Series_Name: Open-File Report Issue_Identification: 2017-1015 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.3133/ofr20171015 Cross_Reference: Citation_Information: Originator: Emily A. Himmelstoss Originator: Amy S. Farris Originator: Rachel E. Henderson Originator: Meredith G. Kratzmann Originator: Ayhan Ergul Originator: Ouya Zhang Originator: Jessica L. Zichichi Originator: E. Robert Thieler Publication_Date: 2018 Title: Digital Shoreline Analysis System (version 5.1): U.S. Geological Survey Software Geospatial_Data_Presentation_Form: software Series_Information: Series_Name: Software Issue_Identification: Version 5.1 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: Use the first two links to access the software. The third link directs to the DSAS project page. Current software at time of use was 5.1. Online_Linkage: https://doi.org/10.5066/P9VW42I0 Online_Linkage: https://code.usgs.gov/cch/dsas/ Online_Linkage: https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas Cross_Reference: Citation_Information: Originator: Emily A. Himmelstoss Originator: Rachel E. Henderson Originator: Meredith G. Kratzmann Originator: Amy S. Farris Publication_Date: 2021 Title: Digital Shoreline Analysis System (DSAS) Version 5.1 User Guide Geospatial_Data_Presentation_Form: Open-File Report Series_Information: Series_Name: Open File Report Issue_Identification: 2021-1091 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: Use the first two links to access the user guide. The third link directs to the DSAS project page. Online_Linkage: https://doi.org/10.3133/ofr20211091 Online_Linkage: https://pubs.er.usgs.gov/publication/ofr20211091 Online_Linkage: https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas Cross_Reference: Citation_Information: Originator: Hillary F. Stockdon Originator: Asbury H. Sallenger Originator: Jeffrey H. List Originator: Rob A. Holman Publication_Date: 2002 Title: Estimation of shoreline position and change using airborne topographic lidar data Geospatial_Data_Presentation_Form: publication Series_Information: Series_Name: Journal of Coastal Research Issue_Identification: vol. 18 Publication_Information: Publication_Place: Charlotte, NC Publisher: Coastal Education and Research Foundation Other_Citation_Details: Suggested citation: Stockdon, H.F., Sallenger, A.H., List, J.H., and Holman, R.A., 2002, Estimation of shoreline position and change using airborne topographic lidar data:  Journal of Coastal Research, v.18, no. 3, p. 502-513., https://www.jstor.org/stable/4299097 Online_Linkage: https://www.jstor.org/stable/4299097 Cross_Reference: Citation_Information: Originator: Peter Ruggiero Originator: Jeffrey H. List Publication_Date: 200909 Title: Improving Accuracy and Statistical Reliability of Shoreline Position and Change Rate Estimates Geospatial_Data_Presentation_Form: publication Series_Information: Series_Name: Journal of Coastal Research Issue_Identification: vol. 255 Publication_Information: Publication_Place: Charlotte, NC Publisher: Coastal Education and Research Foundation Other_Citation_Details: ppg. 1069-1081 Online_Linkage: https://doi.org/10.2112/08-1051.1 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The attributes in this feature class document the positional and measurement uncertainties and datum offsets calculated from averaged slope data (2010-2018) and local wave data. The field names are based on the requirements for use within the Digital Shoreline Analysis System (DSAS) software (Himmelstoss and others, 2018). Logical_Consistency_Report: Each line segment is a copy of the polyline baseline data for the area (which is also available in this data release). The proxy-datum bias and bias uncertainty for each line segment are calculated using the slope data from available lidar surveys for the area (see process steps for details). Attributes populated include numerical values for adjusted bias (bias) and bias uncertainty (bias_uncy). Completeness_Report: The feature contains bias and uncertainty data where lidar data was available for the area. Adjustments were made where necessary after a visual inspection of the coastal shoreline type using high resolution digital imagery. Areas where bias is applied include open ocean sandy shorelines. Areas where bias was not applied include areas in close proximity to inlets, back barrier or marsh areas, rocky headlands and shoreline protection structures. In some cases, the bias was adjusted to match adjacent bias values with similar morphology. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The horizontal location of the bias feature is coincident with the DSAS baseline. The baseline serves as a reference point for transects cast by the DSAS software. The baseline and bias feature do not correspond to any real-world feature. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information Publication_Date: 20181105 Title: U.S. Wave Information Study Edition: DSI-9787 Geospatial_Data_Presentation_Form: historical digital dataset Publication_Information: Publication_Place: 151 Patton Avenue, Asheville, NC Publisher: User Engagement and Services Branch Other_Citation_Details: Data downloaded in 2005 for comuptation of regional average Online_Linkage: https://wis.erdc.dren.mil/index.html Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19900101 Ending_Date: 20000101 Source_Currentness_Reference: range of dates used to determine historical average Source_Citation_Abbreviation: WIS wave data Source_Contribution: Multiple WIS stations closet to the location of interest were used to generate an average wave height value Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 2023 Title: National Data Buoy Center Publication_Information: Publication_Place: Charleston, SC Publisher: Office for Coastal Management Other_Citation_Details: Data downloaded in 2005 for comuptation of regional average Online_Linkage: https://www.ndbc.noaa.gov/ Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2023 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: buoy data Source_Contribution: Mulitiple bouy locations near the region of interest were used to calculate average deep water wave length. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 20000101 Title: 1997 Fall East Coast NOAA/USGS/NASA Airborne LiDAR Assessment of Coastal Erosion (ALACE) Project for the US Coastline Edition: 1.0 Geospatial_Data_Presentation_Form: LAS data Publication_Information: Publication_Place: Charleston, SC Publisher: Office for Coastal Management Other_Citation_Details: Data acccessed/downloaded in 2022 Online_Linkage: https://www.fisheries.noaa.gov/inport/item/48148 Online_Linkage: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/2/index.html Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/-8817775.582977932,3975948.463281728,-8343254.511383558,4352630.138671076/details/2 Type_of_Source_Media: Digital and/or Hardcopy Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19970915 Ending_Date: 19971002 Source_Currentness_Reference: ground condition at the time of survey Source_Citation_Abbreviation: 1997 NC Lidar Source_Contribution: Point cloud data used to extract the 1997 MHW shoreline position and calculate slope around MHW along a profile. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 20131030 Title: 2010 US Army Corps of Engineers (USACE) Joint Airborne Lidar Bathymetry Technical Center of eXpertise (JALBTCX) Southeast Lidar: Florida, Georgia, South Carolina, North Carolina Edition: 1 Geospatial_Data_Presentation_Form: LAS data Publication_Information: Publication_Place: Charleston, SC Publisher: Office for Coastal Management Other_Citation_Details: Data acccessed/downloaded in 2022 Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1070 Online_Linkage: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/1070/index.html Type_of_Source_Media: Digital and/or Hardcopy Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20100504 Ending_Date: 20100616 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: 2010 NC Lidar Source_Contribution: Point cloud data used to extract the 2010 MHW shoreline position and calculate slope around MHW along a profile. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 20220809 Title: 2017 USACE NCMP Topobathy Lidar: East Coast (NY, NJ, DE, MD, VA, NC, SC, GA) Edition: 1 Geospatial_Data_Presentation_Form: LAS data Publication_Information: Publication_Place: Charleston, SC Publisher: Office for Coastal Management Other_Citation_Details: Data acccessed/downloaded in 2022 Online_Linkage: https://www.fisheries.noaa.gov/inport/item/52444 Online_Linkage: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/6329/index.html Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20170609 Ending_Date: 20170907 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: 2017 NC Lidar Source_Contribution: Point cloud data used to extract the 2017 MHW shoreline position and calculate slope around MHW along a profile. Process_Step: Process_Description: Step 1: The proxy-datum bias calculation uses data acquired in the processing for the profile method of shoreline extraction to determine the slope (and uncertainty) around the shoreline position. Similar to the method developed by Stockdon and others (2002) an elevation-based shoreline is extracted from point cloud lidar data using a Matlab-based approach (Matlab version 2015b). Using a coast-following reference line with 20 m spaced cross shore profiles, lidar data is analyzed within a two-meter swath around each shore-perpendicular profile. This method is used to extract the mean high water (MHW) shoreline, as well as slope and uncertainty information. For North Carolina, the slope and uncertainty information at each profile was averaged over time using data from the years 1997, 2010 and 2017 where available. Stockdon, H.F., Sallenger, A.H., List, J.H., and Holman, R.A., 2002, Estimation of shoreline position and change using airborne topographic lidar data:  Journal of Coastal Research, v.18, no. 3, p. 502-513. [Also available at https://www.jstor.org/stable/4299097] Source_Used_Citation_Abbreviation: 1997 NC Lidar Source_Used_Citation_Abbreviation: 2010 NC Lidar Source_Used_Citation_Abbreviation: 2017 NC Lidar Process_Date: 2022 Source_Produced_Citation_Abbreviation: avg slope data Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Amy S. Farris Contact_Position: Oceanographer Contact_Address: Address_Type: mailing and physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543 Country: US Contact_Voice_Telephone: 508-548-8700 x2344 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: afarris@usgs.gov Process_Step: Process_Description: Step 2: There is a known horizontal offset between the datum-based lidar MHW shoreline and the proxy-based historical shorelines on open-ocean sandy beaches that nearly always acts in one direction (Ruggiero and List, 2009). This bias is called the proxy-datum bias (PDB). The PDB is primarily due to wave run-up and thus is affected by the slope of the foreshore and the movement of water (waves, tides) onto the foreshore, see equation for the PDB and the PDB uncertainty in Ruggiero and List, 2009. These equations require beach slope and wave data. Ideally data collected at the time the proxy-based shoreline was collected would be used. For our purposes the PDB is estimated by averaging all available slope data (described in step 1) and averaging at least 10 years of historical wave data to determine 1) the average deep water wavelengh for the region (from bouy data - https://www.ndbc.noaa.gov/) and 2) the average wave height for the region (from the U.S. Wave Information Study - https://wis.erdc.dren.mil/index.html) The resulting values for PDB and PDB uncertainty are stored to a point shapefile at the intersection of the each profile with the coast-following reference line. Ruggiero, P., and List, J.H., 2009, Improving accuracy and statistical reliability of shoreline position and change rate estimates: Journal of Coastal Research, v. 25, no. 5, p. 1069-1081. [Also available at https://www.jstor.org/stable/27752753] National Data Buoy Center, National Oceanic and Atmospheric Administration (NOAA) Stennis Space Center, MS 39529 https://www.ndbc.noaa.gov/ U.S. Wave Information Study, DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce, https://wis.erdc.dren.mil/index.html Source_Used_Citation_Abbreviation: avg slope data Source_Used_Citation_Abbreviation: buoy data Source_Used_Citation_Abbreviation: WIS wave data Process_Date: 2022 Source_Produced_Citation_Abbreviation: bias point data Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Amy S. Farris Contact_Position: Oceanographer Contact_Address: Address_Type: mailing and physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: US Contact_Voice_Telephone: 508-548-8700 x2344 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: afarris@usgs.gov Process_Step: Process_Description: Step 3: To be used with DSAS, the data from the bias points must be connected to a shapefile that is near or adjacent to the DSAS baseline. However, the resulting bias points from the lidar shoreline extraction do not always fall near the baseline. The following steps (Step 4 - Step 9) detail how a series of transects are created to connect the point bias data to a coast following polyline feature. The following process steps were performed by the same person, Rachel E. Henderson. Process_Date: 2022 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Rachel E. Henderson Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: 508-548-8700 x2600 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: rhenderson@usgs.gov Process_Step: Process_Description: Step 4. A personal geodatabase was created and the baseline and sample shorelines for the project area were added (see larger work citation for data). Using DSAS v5.1, the default parameters were set for midshore baseline. Transects were cast using 20-meter spacing, a search distance of 1000 meters, and smoothing distance of 2000 meters. Once cast, the transects were evaluated with the original bias points to ensure the transects overlapped with the bias points and baseline. If needed, the transects were recast with a larger search distance. Process_Date: 2022 Source_Produced_Citation_Abbreviation: transects Process_Step: Process_Description: Step 5. The data from the original bias points (created in step 2) are transferred to the transects, using the ArcTool “Spatial Join”. The resulting Bias_transect contains all the original bias information. The Bias_transect is then converted to a midpoint using the ArcTool "Feature Vertices to Points" and selecting the midpoint option. As the transects were cast with the midshore baseline options, the midpoint will intersect the baseline. The resulting Bias_midpoint, contains all the original bias information. Source_Used_Citation_Abbreviation: bias point data Source_Used_Citation_Abbreviation: transects Process_Date: 2022 Source_Produced_Citation_Abbreviation: Bias_midpoint Process_Step: Process_Description: Step 6. A copy of the baseline is created, and split into 20-meter increments, to match the spacing and detail of the bias_midpoint feature. Points spaced at 20 meters along the original baseline were created using the ArcTool "Generate Points along Lines" at a distance of 20 meters. Then the ArcTool "Split Line at Point" was used with the copy of the baseline, to generate a new feature that has 20 meter segments: Feature_20m. Source_Used_Citation_Abbreviation: Bias_midpoint Process_Date: 2022 Source_Produced_Citation_Abbreviation: Feature_20m Process_Step: Process_Description: Step 7. The data from Bias_midpoint are transferred to the new baseline Feature_20m, using the ArcTool “Spatial Join” resulting in a new polyline feature (Feature_wbias) containing all the original bias information, at 20 meter increments. Source_Used_Citation_Abbreviation: bias point data Process_Date: 2022 Source_Produced_Citation_Abbreviation: Feature_wbias Process_Step: Process_Description: Step 8. The ArcTool "Unsplit Line" was used to reconnect any adjacent 20 meter segment with the same bias, and bias uncertainty values, reducing the number of small segments of bias feature. The final bias feature shapefile holds the bias and the bias uncertainty. These components are used by DSAS v5.1 to apply the proxy-datum bias correction to shoreline change calculations. Source_Used_Citation_Abbreviation: Feature_wbias Process_Date: 2022 Source_Produced_Citation_Abbreviation: Bias_Feature Process_Step: Process_Description: Step 9. The Bias_Feature was imported into a personal geodatabase in ArcCatalog v10.7 by right-clicking on the geodatabase > Import > Feature class (single). The feature class is used with the Digital Shoreline Analysis System (DSAS) v5.1 software to apply the proxy-datum bias to rate calculations. Process_Date: 2022 Process_Step: Process_Description: Step 10. The bias_feature was exported from a personal geodatabase in ArcCatalog v10.5 by right-clicking on the geodatabase > Export > Feature class (single). Coordinate System: UTM Zone 18N (WGS84) Process_Date: 2022 Process_Step: Process_Description: Step 11. The bias_feature was split into four regions along the NC coastline as follows: from the Virginia border to Cape Hatteras (NCnorth), from Cape Hatteras to Cape Lookout (NCcentral), from Cape Lookout to Cape Fear (NCsouth), and from Cape Fear to the South Carolina border (NCwest) Source_Used_Citation_Abbreviation: Bias_Feature Process_Date: 2022 Source_Produced_Citation_Abbreviation: NCnorth_Bias_Feature Source_Produced_Citation_Abbreviation: NCcentral_Bias_Feature Source_Produced_Citation_Abbreviation: NCsouth_Bias_Feature Source_Produced_Citation_Abbreviation: NCwest_Bias_Feature Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: String Point_and_Vector_Object_Count: 84 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 17 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.9996 Longitude_of_Central_Meridian: -81.0 Latitude_of_Projection_Origin: 0.0 False_Easting: 500000.0 False_Northing: 0.0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 0.6096 Ordinate_Resolution: 0.6096 Planar_Distance_Units: meters Geodetic_Model: Horizontal_Datum_Name: WGS_1984 Ellipsoid_Name: WGS_84 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257223563 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: NCwest_bias_feature Entity_Type_Definition: Table containing attribute information associated with the data set. Entity_Type_Definition_Source: U.S. Geological Survey (USGS) Attribute: Attribute_Label: FID Attribute_Definition: Internal feature number. Attribute_Definition_Source: Esri Attribute_Domain_Values: Unrepresentable_Domain: Sequential unique whole numbers that are automatically generated. Attribute: Attribute_Label: Shape Attribute_Definition: Feature geometry. Attribute_Definition_Source: Esri Attribute_Domain_Values: Unrepresentable_Domain: Feature geometry. The feature is a polyline shapefile. Attribute: Attribute_Label: OBJECTID Attribute_Definition: Internal feature number. Attribute_Definition_Source: Esri Attribute_Domain_Values: Unrepresentable_Domain: Sequential unique whole numbers that are automatically generated. Attribute: Attribute_Label: bias Attribute_Definition: This field heading is case-sensitive and name specific. The field contains a proxy-datum bias value describing the unidirectional horizontal offset (in meters) between the MHW elevation of the lidar data and HWL shoreline positions. Values of 0.001 represent areas where no bias was applied. For details on the components that make up the proxy-datum bias, refer to the Methods section of USGS Open-File Report 2010-1118 cross-referenced in the metadata Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.001 Range_Domain_Maximum: 16.912 Attribute: Attribute_Label: bias_uncy Attribute_Definition: The field contains the plus/minus horizontal uncertainty (meters) in the lidar shoreline position at each cross-shore beach profile. Values of 0.001 represent areas where no bias was applied. For details on the components that make up this uncertainty, refer to the Methods section of USGS Open-File report 2010-1118 cross-referenced in the metadata. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.001 Range_Domain_Maximum: 8.776 Attribute: Attribute_Label: Shape_Leng Attribute_Definition: Length of feature in meter units (WGS 1984 UTM Zone 17N) Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 1.899 Range_Domain_Maximum: 1079.999 Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: USGS ScienceBase Contact_Address: Address_Type: mailing and physical Address: Federal Center, Building 810, MS 302 City: Denver State_or_Province: CO Postal_Code: 88025 Contact_Voice_Telephone: 1-888-275-8747 Contact_Electronic_Mail_Address: sciencebase@usgs.gov Resource_Description: The dataset contains the polyline shapefile of the proxy-datum bias and its uncertainty, (NCwest_bias_feature.shp and other shapefile components), browse graphic (NCwest_bias_feature_browse.PNG), and the FGDC CSDGM metadata in XML format. Distribution_Liability: Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: Shapefile Format_Version_Number: ArcGIS 10.7.1 Format_Specification: Esri polyline shapefile Format_Information_Content: These files (.cpg, .dbf, .prj, .sbn, .sbx, .shp, and .shx) are a collection of files with a common filename prefix and must be downloaded and stored in the same directory. Together they are the components of the shapefile. Additional files of the same name included are FGDC CSDGM-compliant metadata in XML format. Transfer_Size: 0.14 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://doi.org/10.5066/P9HYNUNV Network_Resource_Name: https://www.sciencebase.gov/catalog/file/get/64de701cd34e5f6cd55350cf Network_Resource_Name: https://www.sciencebase.gov/catalog/item/get/64de701cd34e5f6cd55350cf Access_Instructions: The first link is to the USGS publication page, the second link downloads all the data on the landing page, and the third link is to the dataset landing page. Fees: None Metadata_Reference_Information: Metadata_Date: 20231023 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Marie K. Bartlett Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: US Contact_Voice_Telephone: 508-548-8700 x 2306 Contact_Electronic_Mail_Address: whsc_data_contact@usgs.gov Contact_Instructions: The metadata contact email address is a generic address in the event the person is no longer with USGS. Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time