Metadata: Identification_Information: Citation: Citation_Information: Originator: Meredith G. Kratzmann Originator: Amy S. Farris Publication_Date: 20260622 Title: Alabama: bias feature containing proxy-datum bias information used in shoreline change rate calculations Edition: 1.0 Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P1JE2KSO 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/P1JE2KSO Online_Linkage: https://www.sciencebase.gov/catalog/item/69e2b0f0b66b0195694c11f1 Larger_Work_Citation: Citation_Information: Originator: Meredith G. Kratzmann Originator: Amy S. Farris Originator: Kathryn M. Weber Publication_Date: 2026 Title: National Shoreline Change—A GIS compilation of vector shorelines and associated shoreline change data from the 1800s to the 2020s for the coast of Alabama Edition: 1.0 Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P1JE2KSO Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: suggested citation: Kratzmann, M.G., Farris, A.S., and Weber, K.M., 2026, National Shoreline Change—A GIS compilation of vector shorelines and associated shoreline change data from the 1800s to the 2020s for the coast of Alabama: U.S. Geological Survey data release, https://doi.org/10.5066/P1JE2KSO. Online_Linkage: https://doi.org/10.5066/P1JE2KSO Online_Linkage: https://www.sciencebase.gov/catalog/item/69e2a7d5b66b0195694c1197 Description: Abstract: The U.S. Geological Survey (USGS) maintains shoreline positions for the United States coasts from various historical sources, such as aerial photographs or topographic surveys, and contemporary sources, such as lidar-point clouds and digital elevation models. Shorelines are compiled in a Geographic Information System (GIS) and analyzed in the USGS Digital Shoreline Analysis System (DSAS) software to calculate rates of change. Keeping a record of historical shoreline positions is an effective method to monitor change over time, enabling scientists to identify areas most susceptible to erosion or accretion. These data can help coastal managers understand which areas of the coast are vulnerable to change. The shoreline positions and shoreline change rates provide actionable information to homeowners, coastal communities, and managers of public and private properties to improve resiliency for coastal hazards. Purpose: Shoreline positions from the mid-1800s through the 2020s were used to calculate shoreline change rates for Alabama using the Digital Shoreline Analysis System v6.1 software. The shorelines dataset contains a combination of proxy-based (e.g., high water line) and datum-based (e.g., mean high water) shorelines. The bias feature is a polyline shapefile to be used in DSAS and is a representation of the proxy-datum bias (PDB) with bias uncertainty values. These PDB data are used to reconcile the offset between proxy- and datum-based shorelines so they can be directly compared when calculating shoreline change rates. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2026 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -88.350587 East_Bounding_Coordinate: -87.517445 North_Bounding_Coordinate: 30.278659 South_Bounding_Coordinate: 30.216387 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: Shoreline change Theme_Keyword: Digital Shoreline Analysis System Theme_Keyword: DSAS Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: CMGP Theme_Keyword: Woods Hole Coastal and Marine Science Center Theme_Keyword: WHCMSC Theme_Keyword: Linear Regression Rate Theme_Keyword: LRR Theme_Keyword: High Water Line Theme_Keyword: HWL Theme_Keyword: Mean High Water Theme_Keyword: MHW Theme_Keyword: proxy-datum bias Theme_Keyword: PDB Theme_Keyword: Bias feature Theme_Keyword: Bias Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: geospatial datasets Theme_Keyword: coastal processes Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:69e2b0f0b66b0195694c11f1 Place: Place_Keyword_Thesaurus: GNIS Place_Keyword: State of Alabama Place_Keyword: Dauphin Island Place_Keyword: Fort Morgan Alabama Place_Keyword: Gulf Shores Place: Place_Keyword_Thesaurus: None Place_Keyword: Gulf Coast Place_Keyword: Bon Secour National Wildlife Refuge Place_Keyword: United States of America Place_Keyword: North America Access_Constraints: No access constraints. Please see 'Distribution Information' for details. Use_Constraints: These data are marked with a Creative Commons CC0 1.0 Universal License. These data are in the public domain and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. These data were automatically generated using the DSAS v6.1 software application. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. 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: U.S. Geological Survey Contact_Person: Meredith G. Kratzmann Contact_Address: Address_Type: mailing and physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: 508-548-8700 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: mkratzmann@contractor.usgs.gov Browse_Graphic: Browse_Graphic_File_Name: https://www.sciencebase.gov/catalog/file/get/69e2b0f0b66b0195694c11f1?name=AL_bias.png&allowOpen=true Browse_Graphic_File_Description: Map view of data. Orange line indicates extent of the bias feature for Alabama. Browse_Graphic_File_Type: PNG Native_Data_Set_Environment: Microsoft Windows 11 Enterprise; Esri ArcGIS Pro 3.5.5 Cross_Reference: Citation_Information: Originator: Rachel E. Henderson Originator: Amy S. Farris Originator: Meredith G. Kratzmann Originator: Marie K. Bartlett Originator: Ayhan Ergul Originator: John McAndrews Originator: Raison Cibaj Originator: Jessica L. Zichichi Originator: Emily A. Himmelstoss Originator: E. Robert Thieler Publication_Date: 2026 Title: Digital Shoreline Analysis System version 6.1 Geospatial_Data_Presentation_Form: publication Series_Information: Series_Name: software release Issue_Identification: version 6.1.177 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: Use the first link to access the publication page. The second link is to the current version of DSAS (v6.1). The third link directs to the DSAS project page. Online_Linkage: https://doi.org/10.5066/P1NHMJNC 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: 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: n/a Publisher: Coastal Education and Research Foundation Other_Citation_Details: pp. 1069-1081 Online_Linkage: https://doi.org/10.2112/08-1051.1 Cross_Reference: Citation_Information: Originator: Amy S. Farris Originator: Kathryn M. Weber Originator: Kara S. Doran Originator: Jeffrey H. List Publication_Date: 2018 Title: Comparing methods used by the U.S. Geological Survey Coastal and Marine Geology Program for deriving shoreline position from lidar data Series_Information: Series_Name: Open-File Report Issue_Identification: 2018–1121 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.3133/ofr20181121 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: Woods Hole, MA Publisher: U.S. Geological Survey Online_Linkage: https://www.jstor.org/stable/4299097 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The attributes in the bias feature shapefile record positional and measurement uncertainties and proxy-datum offsets calculated from averaged slope data and local wave data (see process steps for details). The field names are based on the requirements for use within DSAS. Attributes for each segment include the bias value (bias), bias uncertainty (bias_uncy), and a unique identification number (id). Logical_Consistency_Report: The bias feature polyline is a copy of the Alabama baseline that is split into segments containing PDB data (see process steps for details). Completeness_Report: The bias feature is complete and contains data necessary to apply the proxy-datum bias when calculating shoreline change rates in DSAS v6.1. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The horizontal location of the bias feature is coincident with the baseline which 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: Meredith G. Kratzmann Publication_Date: 2026 Title: Alabama: baseline generated to calculate shoreline change rates in Kratzmann, M.G., Farris, A.S., and Weber, K.M., 2026, National Shoreline Change—A GIS compilation of vector shorelines and associated shoreline change data from the 1800s to the 2020s for the coast of Alabama: U.S. Geological Survey data release, https://doi.org/10.5066/P1JE2KSO Edition: 1.0 Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P1JE2KSO Publication_Information: Publication_Place: Woods Hole Coastal and Marine Science Center, Woods Hole, MA Publisher: U.S. Geological Survey Other_Citation_Details: The first link is to the larger work, the second link is to the baseline dataset. Online_Linkage: https://doi.org/10.5066/P1JE2KSO Online_Linkage: https://www.sciencebase.gov/catalog/item/69e2afc2b66b0195694c11e3 Type_of_Source_Media: digital data Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2026 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: AL_baseline Source_Contribution: Baseline segments for Alabama (part of this same data release https://doi.org/10.5066/P1JE2KSO) are used by DSAS to cast measurement transects. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management Partners Publication_Date: 2026 Title: 2010 USACE NCMP Topobathy Lidar: Gulf Coast (AL, FL) Geospatial_Data_Presentation_Form: vector digital dataset Publication_Information: Publication_Place: Charleston, SC Publisher: Office for Coastal Management Other_Citation_Details: Point cloud data were downloaded for Alabama. Projection = NAD_1983_2011_UTM_Zone_16N. Data accessed and downloaded in 08/2025 and 09/2025. Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1064 Online_Linkage: https://www.fisheries.noaa.gov/inport/item/50083 Type_of_Source_Media: digital data Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 201001 Ending_Date: 201003 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: 2010 AL lidar Source_Contribution: Point cloud data used to extract the 2010 MHW shoreline position and calculate slope. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management Partners Publication_Date: 2026 Title: 2016 USACE NCMP Topobathy Lidar: Gulf Coast (AL, FL, MS, TX) Geospatial_Data_Presentation_Form: vector digital dataset Publication_Information: Publication_Place: Charleston, SC Publisher: Office for Coastal Management Other_Citation_Details: Point cloud data were downloaded for Alabama. Projection = NAD_1983_2011_UTM_Zone_16N. Data accessed and downloaded in 06/2025. Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=5186 Online_Linkage: https://www.fisheries.noaa.gov/inport/item/49738 Type_of_Source_Media: digital data Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20160723 Ending_Date: 20161010 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: 2016 AL lidar Source_Contribution: Point cloud data used to extract the 2016 MHW shoreline position and calculate slope. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management Partners Publication_Date: 2026 Title: 2022 USACE NCMP Topobathy Lidar: Gulf Coast (AL, FL, MS) Geospatial_Data_Presentation_Form: vector digital dataset Publication_Information: Publication_Place: Charleston, SC Publisher: Office for Coastal Management Other_Citation_Details: Point cloud data were downloaded for Alabama. Projection = NAD_1983_2011_UTM_Zone_16N. Data accessed and downloaded in 08/2025. Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=10314 Online_Linkage: https://www.fisheries.noaa.gov/inport/item/75435 Type_of_Source_Media: digital data Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20220717 Ending_Date: 20220719 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: 2022 AL lidar Source_Contribution: Point cloud data used to extract the 2022 MHW shoreline position and calculate slope. Source_Information: Source_Citation: Citation_Information: Originator: National Oceanic and Atmospheric Administration (NOAA) Originator: National Weather Service (NWS) Publication_Date: unknown Title: National Data Buoy Center Geospatial_Data_Presentation_Form: data viewer Publication_Information: Publication_Place: Stennis Space Center, MS Publisher: National Oceanic and Atmospheric Administration Online_Linkage: https://www.ndbc.noaa.gov/ Type_of_Source_Media: digital data Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 2010 Ending_Date: 2022 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: Buoy data Source_Contribution: Buoy data used for processing lidar shorelines extracted using the profile method and calculating the proxy-datum bias for Alabama. Source_Information: Source_Citation: Citation_Information: Originator: National Oceanic and Atmospheric Administration (NOAA) Publication_Date: unknown Title: U.S. Wave Information Study (WIS) Geospatial_Data_Presentation_Form: data viewer Publication_Information: Publication_Place: Silver Spring, MD Publisher: National Centers for Environmental Information, NOAA, U.S. Department of Commerce Online_Linkage: https://www.ncei.noaa.gov/access/metadata/landing-page/bin/iso?id=gov.noaa.ncdc:C00071 Online_Linkage: https://www.ncei.noaa.gov/ Type_of_Source_Media: digital data Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 2010 Ending_Date: 2022 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: WIS data Source_Contribution: The WIS project produced an online database of hindcast, nearshore wave conditions covering U.S. coasts. Data used for calculating the proxy-datum bias for Alabama. Source_Information: Source_Citation: Citation_Information: Originator: Rachel E. Henderson Originator: Amy S. Farris Originator: Meredith G. Kratzmann Originator: Marie K. Bartlett Originator: Ayhan Ergul Originator: John McAndrews Originator: Raison Cibaj Originator: Jessica L. Zichichi Originator: Emily A. Himmelstoss Originator: E. Robert Thieler Publication_Date: 2026 Title: Digital Shoreline Analysis System version 6.1 Geospatial_Data_Presentation_Form: publication Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/P1NHMJNC Online_Linkage: https://code.usgs.gov/cch/dsas Online_Linkage: https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas Type_of_Source_Media: software Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 2026 Ending_Date: 2026 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: DSAS v6.1 Source_Contribution: Software used to cast temporary transects for the purpose of creating the bias feature for Alabama. Process_Step: Process_Description: Bias feature creation step 1: COLLECTING SLOPE DATA FROM POINT CLOUD LIDAR DATA. The proxy-datum bias calculation is made possible by utilizing data acquired during processing for the profile method of shoreline extraction similar to the one developed by Stockdon and others (2002). The method extracts an elevation-based shoreline from point cloud lidar data using a Matlab-based approach (Matlab version R2024A). Using a coast-following reference line with 20-m-spaced cross shore profiles, lidar data are analyzed within a two-meter swath around each profile. This method is used to extract the mean high water (MHW) shoreline, as well as slope and uncertainty information at each profile. For Alabama, slope and uncertainty were averaged using the lidar dataset years 2010, 2016 and 2022, where available. Source_Used_Citation_Abbreviation: 2010 AL lidar Source_Used_Citation_Abbreviation: 2016 AL lidar Source_Used_Citation_Abbreviation: 2022 AL lidar Process_Date: 2025 Source_Produced_Citation_Abbreviation: Average slope data Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Amy S. Farris 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: Bias feature creation step 2: CALCULATING THE PROXY-DATUM BIAS. There is a known horizontal offset between datum-based (MHW) shorelines and proxy-based (HWL) 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 or "bias"). 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, however, for our purposes the PDB is estimated by averaging all available slope data and averaging at least 10 years of historical wave data from a nearby buoy (National Data Buoy Center) and the U.S. Wave Information Study (WIS). The resulting bias and bias uncertainty information is stored in a shapefile as points at the intersection of each profile and the coast-following reference line. Source_Used_Citation_Abbreviation: Buoy data Source_Used_Citation_Abbreviation: WIS data Source_Used_Citation_Abbreviation: Average slope data Process_Date: 2025 Source_Produced_Citation_Abbreviation: Bias points 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: Bias feature creation step 3: TRANSECTS CAST TO CONNECT BIAS POINTS AND BASELINE. In order to be used in DSAS, data from the bias points must be connected to a shapefile that is near or coincident with the baseline. However, the bias points that result from the lidar shoreline extraction process (steps 1 and 2) do not always fall near the baseline. Transects were created for the sole purpose of connecting the bias points to the baseline. Transects were cast using DSAS v6.1 at 20-meter spacing, length= 1200 meters, smoothing value= 2000 meters. Transects were exported from DSAS and evaluated with the bias points in ArcGIS Pro v3.5.5 to ensure the transects were long enough. This and the following process steps were performed by the same person: Meredith Kratzmann. Source_Used_Citation_Abbreviation: DSAS v6.1 Process_Date: 2026 Source_Produced_Citation_Abbreviation: 20-meter transects Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Meredith Kratzmann Contact_Address: Address_Type: Mailing and Physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543 Contact_Voice_Telephone: 508-548-8700 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: mkratzmann@contractor.usgs.gov Process_Step: Process_Description: Bias feature creation step 4: SPLIT BASELINE. In ArcGIS Pro v3.5.5, points were established along the baseline by a distance of 20 meters using the geoprocessing tool: Data Management Tools > Sampling > Generate Points Along Lines. Then, the baseline was split at those points using the tool: Data Management Tools > Features > Split Line at Point. Source_Used_Citation_Abbreviation: AL_baseline Process_Date: 2026 Source_Produced_Citation_Abbreviation: baseline20m Process_Step: Process_Description: Bias feature creation step 5: JOIN BIAS POINTS TO TRANSECTS. In ArcGIS Pro v3.5.5, bias points were joined to transects using the geoprocessing tool: Analysis Tools > Overlay > Spatial Join. Then, the transects that now have the bias were converted to points (midpoint) using the tool: Data Management Tools > Features > Feature Vertices To Points. Source_Used_Citation_Abbreviation: 20-meter transects Source_Used_Citation_Abbreviation: Bias points Process_Date: 2026 Source_Produced_Citation_Abbreviation: trans_bias_PT Process_Step: Process_Description: Bias feature creation step 6: CREATE BIAS FEATURE POLYLINE. In ArcGIS Pro v3.5.5, the transect bias points generated in process step 5 were joined to the baseline split into 20-meter segments (process step 4) using the geoprocessing tool: Analysis Tools > Overlay > Spatial Join. Then, the split line that now has bias data was unsplit using the tool: Data Management Tools > Features > Unsplit Line. The resultant file is the bias feature that was renamed and used in the long-term shoreline change rate calculations for Alabama. Source_Used_Citation_Abbreviation: baseline20m Source_Used_Citation_Abbreviation: trans_bias_PT Process_Date: 2026 Source_Produced_Citation_Abbreviation: AL_bias Process_Step: Process_Description: The baseline shapefile was projected in ArcGIS Pro v3.5.5 > Geoprocessing > Data Management Tools > Projections and Transformations > Project. Parameters: Input Coordinate System - NAD_1983_2011_UTM_Zone_16N; Output Coordinate System - GCS_WGS_1984; transformation = WGS_1984_(ITRF08)_To_NAD_1983_2011. Process_Date: 2026 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: Geographic: Latitude_Resolution: 0.0000001 Longitude_Resolution: 0.0000001 Geographic_Coordinate_Units: Decimal degrees 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: AL_bias.shp Entity_Type_Definition: Proxy-datum bias and uncertainty values for the Alabama coastal region. Entity_Type_Definition_Source: U.S. Geological Survey 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: Coordinates defining the features. Attribute: Attribute_Label: bias Attribute_Definition: The proxy-datum bias value describing the unidirectional horizontal offset (in meters) between MHW elevation and HWL shoreline positions. The average value for AL is 4.73 meters. Attribute_Definition_Source: U.S. Geological Survey Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 4.33 Range_Domain_Maximum: 5.99 Attribute_Units_of_Measure: meters Attribute: Attribute_Label: bias_uncy Attribute_Definition: The plus/minus horizontal uncertainty (meters) in the lidar shoreline position at each cross-shore beach profile. Attribute_Definition_Source: U.S. Geological Survey Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 2.24 Range_Domain_Maximum: 3.62 Attribute_Units_of_Measure: meters Attribute: Attribute_Label: id Attribute_Definition: A unique identification number for each segment. Attribute_Definition_Source: U.S. Geological Survey Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 1 Range_Domain_Maximum: 84 Attribute_Units_of_Measure: meters Overview_Description: Entity_and_Attribute_Overview: The entity and attribute information provided here describes the tabular data associated with the bias feature for Alabama. Please review the individual attribute descriptions for detailed information. Entity_and_Attribute_Detail_Citation: U.S. Geological Survey Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey - GS ScienceBase Contact_Address: Address_Type: mailing address Address: Denver Federal Center, Building 810, Mail Stop 302 City: Denver State_or_Province: CO Postal_Code: 80225 Country: United States Contact_Voice_Telephone: 1-888-275-8747 Contact_Electronic_Mail_Address: sciencebase@usgs.gov Resource_Description: The dataset contains the polyline baselines used for the analysis of shoreline data (SHP and other shapefile components), browse graphic, and the FGDC CSDGM 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 for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: Shapefile Format_Version_Number: Esri ArcGIS Pro 3.5.5 Format_Specification: Esri polyline shapefile Format_Information_Content: These files (.cpg, .dbf, .prj, .sbn, .sbx, .shp, .html, 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 and include FGDC CSDGM-compliant metadata in HTML format. File_Decompression_Technique: Unzip Transfer_Size: 0.068 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://doi.org/10.5066/P1JE2KSO Network_Resource_Name: https://www.sciencebase.gov/catalog/item/69e2b0f0b66b0195694c11f1 Network_Resource_Name: https://www.sciencebase.gov/catalog/file/get/69e2b0f0b66b0195694c11f1 Access_Instructions: The first link is to the USGS publication page, the second link is to the dataset page, and the third link downloads the data. Fees: None Technical_Prerequisites: These data are available in a polyline shapefile format. The user must have software to read and process the data components of a shapefile. Metadata_Reference_Information: Metadata_Date: 20260622 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Meredith G. Kratzmann Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: 508-548-8700 Contact_Facsimile_Telephone: 508-457-2310 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 Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time