Metadata: Identification_Information: Citation: Citation_Information: Originator: Amy S. Farris Originator: Kathryn M. Weber Publication_Date: 20241203 Title: Beach foreshore slope for the U.S. Gulf of Mexico Edition: 1 Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: data release Issue_Identification: doi:10.5066/P14JUVPT 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 Other_Citation_Details: Suggested citation: Farris, A.S., and Weber, K.M., 2024, Beach foreshore slope for the U.S. Gulf of Mexico: U.S. Geological Survey data release, https://doi.org/10.5066/P14JUVPT Online_Linkage: https://doi.org/10.5066/P14JUVPT Online_Linkage: https://www.sciencebase.gov/catalog/item/66fae79fd34e6d68f514c592 Description: Abstract: This data release contains foreshore slopes for primarily open-ocean sandy beaches along the United States portion of the Gulf of Mexico (Texas through Florida). The slopes were calculated while extracting shoreline position from lidar point cloud data collected between 2001 and 2018. The shoreline positions have been previously published, but the slopes have not. An alongshore reference baseline was defined, and then 20-meter spaced cross-shore beach transects were created perpendicular to the baseline. All data points within 1 meter (alongshore) of each transect were associated with that transect. For each transect, the points on the foreshore were identified, and a linear regression was fit through the foreshore points. Beach slope was defined as the slope of the regression. The regression was evaluated at the elevation of mean high water (MHW) to yield the cross-shore location of the shoreline. In areas where more than one lidar survey is available, the slopes from each survey are provided. Most of the slopes are for sandy beaches, but some transects cross seawalls or other structures that cause steeper slopes. The slope data files (slopeData_GulfCoast.csv and slopeData_GulfCoast.shp) contain beach slope, the location at which the beach slope data were calculated (the shoreline position), and the estimated uncertainty of the shoreline position. The reference line data files (referenceLine_GulfCoast.csv and referenceLine_GulfCoast.shp) contain information about the reference baseline, the cross-shore transects, and the MHW values used to estimate the shoreline location. Both file types *.csv (ascii files containing comma separated values) and *.shp (binary files supported by Esri known as shapefiles) contain the same information. Both file types are provided as a convenience to the user. Purpose: Beach slope is a critical metric for coastal hazards science. Foreshore beach slope is a key variable in a variety of nearshore process parameterizations. In particular it is necessary when extracting shorelines from satellite imagery. Shorelines derived from satellite data must be tidally-corrected to a reference elevation using the slope of the beach. The beach slope data presented here will be beneficial for advancing our understanding of coastal processes and for quantifying and predicting shoreline change and storm impacts along the Gulf Coast of the US. Supplemental_Information: The shorelines that were derived when these slopes were calculated can be accessed through the USGS National Shoreline Change Data Catalog: https://www.sciencebase.gov/catalog/item/5b97f1b4e4b0702d0e842183 Note that the transect numbers used in those publications are different that the transect numbers used here. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20010909 Ending_Date: 20181104 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -97.3793 East_Bounding_Coordinate: -81.6822 North_Bounding_Coordinate: 30.3972 South_Bounding_Coordinate: 25.8470 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: environment Theme_Keyword: oceans Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: USGS Theme_Keyword: U.S. Geological Survey Theme_Keyword: Coastal and Marine Hazards and Resources Program Theme_Keyword: Woods Hole Coastal and Marine Science Center Theme_Keyword: WHCMSC Theme_Keyword: beach slope Theme_Keyword: foreshore Theme_Keyword: shoreline Theme_Keyword: mean high water Theme_Keyword: MHW Theme: Theme_Keyword_Thesaurus: USGS thesaurus Theme_Keyword: coastal processes Theme_Keyword: geospatial datasets Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:66fae79fd34e6d68f514c592 Place: Place_Keyword_Thesaurus: None Place_Keyword: United States Place_Keyword: Gulf Coast Place_Keyword: Gulf of Mexico Coast Place_Keyword: Texas Place_Keyword: Louisiana Place_Keyword: Mississippi Place_Keyword: Alabama Place_Keyword: Florida Access_Constraints: None. Use_Constraints: 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. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Amy S. Farris Contact_Organization: U.S. Geological Survey Contact_Position: Oceanographer Contact_Address: Address_Type: mailing address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543 Country: US Contact_Voice_Telephone: 508-548-8700 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: afarris@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: https://www.sciencebase.gov/catalog/file/get/66fae79fd34e6d68f514c592?name=browseGraphicGulfCoast.jpg&allowOpen=true Browse_Graphic_File_Description: Small section of data showing reference baseline and slope data Browse_Graphic_File_Type: JPEG Native_Data_Set_Environment: Windows 10, Matlab versions R2007a and R2023a. Cross_Reference: Citation_Information: Originator: Amy S. Farris Originator: Kathryn M. Weber Publication_Date: 2024 Title: Beach foreshore slope for the West Coast of the United States (ver. 1.1, September 2024) Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P137S83C Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/P137S83C Cross_Reference: Citation_Information: Originator: Amy S. Farris Originator: Kathryn M. Weber Publication_Date: 2024 Title: Beach foreshore slope for the East Coast of the United States Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P13FC6SW Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/P13FC6SW 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: Kathryn M. Weber Originator: Jeffrey H. List Originator: Karen L.M. Morgan Publication_Date: 2005 Title: An operational mean high water datum for determination of shoreline position from topographic lidar data Series_Information: Series_Name: Open-File Report Issue_Identification: 2005-1027 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.3133/ofr20051027 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The data provided here consist of estimates of the foreshore slopes of primarily sandy beaches along the U.S. Gulf of Mexico Coast. The beach slopes were calculated using many different lidar surveys conducted from 2001 to 2018. The accuracy of the lidar point cloud elevation data from these surveys varies, with the oldest surveys being the least accurate. There are several factors that affect the accuracy of the beach slopes. These vary by survey and include: the accuracy of the lidar data, the scatter in the lidar data, the density of lidar data on the foreshore, the width of the foreshore, and the slope of the foreshore. In addition, this methodology assumes that the slope of the foreshore is constant along the transect from the water to the berm. While this assumption is usually valid, we do not know how valid it is at any individual transect. The best way to assess the accuracy of a given slope value is to compare it to adjacent values in both space and time. Logical_Consistency_Report: Beach slopes were automatically calculated for each transect during the shoreline extraction process. If no shoreline point was found on a transect or if the shoreline point did not pass QA/QC procedures, that transect will not have a value for slope. There was more than one lidar survey available for many transects; shorelines and slopes were calculated for each lidar survey. The beach slopes vary due to both measurement error and natural variability of the system. Transect numbers are unique for each state, or if the state is divided into regions, for each region. Completeness_Report: Beach slopes were calculated primarily on open-ocean, sandy beaches. However, be aware that some slopes are higher than expected because some transects cross structures like seawalls. Most locations have more than one estimate of beach slope because multiple lidar surveys were conducted and processed. There are some large gaps in the slope data that are due to gaps in the lidar data. Additional small gaps were created when data that did not pass our QA/QC procedures were removed. The baselines (and transects) sometimes continue across inlets, marshes or other areas where shorelines were not extracted. All transects are listed, even transects for which no shoreline was found. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: There is no horizontal component of accuracy associated with beach slope. There is horizontal accuracy associated with each lidar dataset from which these data were estimated. This accuracy varies by data set (see the lidar survey metadata). The foreshore beach slope values are provided at our estimated shoreline position. Our estimated horizontal accuracy of shoreline position is provided with the data, see the attribute "ShoreUncy". See Process Step for details about how this value was calculated. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: There is no vertical component of accuracy associated with beach slope. There is vertical accuracy associated with each lidar dataset from which these data were estimated. This accuracy varies by data set (see the lidar survey metadata). The reference line data file contains the values of mean high water (MHW) that were used to estimate the shoreline position. There is vertical accuracy associated with these values. These values were taken from Weber and others (2005) and do not vary continuously along the coast, but rather are constant for long stretches of coastline. The value at any particular point is estimated to be within 15 cm of the 'true' value. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 20161215 Title: 2015 USACE NCMP Topobathy Lidar: Florida Gulf Coast Geospatial_Data_Presentation_Form: tabular digital data Publication_Information: Publication_Place: Charleston, SC Publisher: NOAA Office for Coastal Management (NOAA/OCM) Online_Linkage: https://www.fisheries.noaa.gov/inport/item/49720 Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=5183 Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20150606 Ending_Date: 20150630 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: FL_2015 Source_Contribution: The bare-earth lidar point cloud data in LAS format were used to calculate beach slope using methods described in the process steps. The point data were downloaded using the cart feature in the appropriate UTM zone projection with NAD83 horizontal datum and NAVD88 vertical datum (meters), in the most recent Geoid. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 20120823 Title: 2010 US Army Corps of Engineers (USACE) Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBTCX) Topobathy Lidar: Alabama Coast and Florida Gulf Coast Geospatial_Data_Presentation_Form: tabular digital data Publication_Information: Publication_Place: Charelston, SC Publisher: NOAA Office for Coastal Management (NOAA/OCM) Online_Linkage: https://www.fisheries.noaa.gov/inport/item/50083 Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1064 Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20100620 Ending_Date: 20100722 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: FL_AL_2010 Source_Contribution: The bare-earth lidar point cloud data in LAS format were used to calculate beach slope using methods described in the process steps. The point data were downloaded using the cart feature in the appropriate UTM zone projection with NAD83 horizontal datum and NAVD88 vertical datum (meters), in the most recent Geoid. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 20220809 Title: 2017 USACE FEMA Topobathy Lidar: Florida East Coast, Florida Keys, and Collier County (Post Hurricane Irma) Geospatial_Data_Presentation_Form: tabular digital data Publication_Information: Publication_Place: Charleston, SC Publisher: NOAA Office for Coastal Management (NOAA/OCM) Online_Linkage: https://www.fisheries.noaa.gov/inport/item/49723 Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=6330 Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20170918 Ending_Date: 20171025 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: FL_2017 Source_Contribution: The bare-earth lidar point cloud data in LAS format were used to calculate beach slope using methods described in the process steps. The point data were downloaded using the cart feature in the appropriate UTM zone projection with NAD83 horizontal datum and NAVD88 vertical datum (meters), in the most recent Geoid. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 20040715 Title: 2001 USGS/NASA Airborne Topographic Mapper (ATM) Lidar: Coastal Alabama, Florida, Louisiana, Mississippi, Texas Geospatial_Data_Presentation_Form: tabular digital data Publication_Information: Publication_Place: Charleston, SC Publisher: NOAA Office for Coastal Management (NOAA/OCM) Online_Linkage: https://www.fisheries.noaa.gov/inport/item/50098 Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=525 Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20010909 Ending_Date: 20011013 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: FL_TX_2001 Source_Contribution: The bare-earth lidar point cloud data in LAS format were used to calculate beach slope using methods described in the process steps. The point data were downloaded using the cart feature in the appropriate UTM zone projection with NAD83 horizontal datum and NAVD88 vertical datum (meters), in the most recent Geoid. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 20170913 Title: 2016 USACE NCMP Topobathy Lidar DEM: Gulf Coast (AL, FL, MS, TX) Geospatial_Data_Presentation_Form: tabular digital data Publication_Information: Publication_Place: Charleston, SC Publisher: NOAA Office for Coastal Management (NOAA/OCM) Online_Linkage: https://www.fisheries.noaa.gov/inport/item/49427 Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=6371 Type_of_Source_Media: Digital 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: FL_2016 Source_Contribution: The bare-earth lidar point cloud data in LAS format were used to calculate beach slope using methods described in the process steps. The point data were downloaded using the cart feature in the appropriate UTM zone projection with NAD83 horizontal datum and NAVD88 vertical datum (meters), in the most recent Geoid. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 20181108 Title: 2018 USACE FEMA Post-Michael Topobathy Lidar: Florida Panhandle Geospatial_Data_Presentation_Form: tabular digital data Publication_Information: Publication_Place: Charleston, SC Publisher: NOAA Office for Coastal Management (NOAA/OCM) Online_Linkage: https://www.fisheries.noaa.gov/inport/item/54682 Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=8625 Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20181024 Ending_Date: 20181104 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: FL_2018 Source_Contribution: The bare-earth lidar point cloud data in LAS format were used to calculate beach slope using methods described in the process steps. The point data were downloaded using the cart feature in the appropriate UTM zone projection with NAD83 horizontal datum and NAVD88 vertical datum (meters), in the most recent Geoid. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 20061016 Title: 2005 US Army Corps of Engineers (USACE) Post-Hurricane Katrina LiDAR: Mississippi and Western Alabama Geospatial_Data_Presentation_Form: tabular digital data Publication_Information: Publication_Place: Charleston,SC Publisher: NOAA Office for Coastal Management (NOAA/OCM) Online_Linkage: https://www.fisheries.noaa.gov/inport/item/49953 Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=28 Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20050919 Ending_Date: 20051009 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: MS_2005 Source_Contribution: The bare-earth lidar point cloud data in LAS format were used to calculate beach slope using methods described in the process steps. The point data were downloaded using the cart feature in the appropriate UTM zone projection with NAD83 horizontal datum and NAVD88 vertical datum (meters), in the most recent Geoid. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 20110901 Title: 2009 USACE NCMP Topobathy Lidar: AL, LA, MS, TX (Post Hurricanes Gustav Ike) Geospatial_Data_Presentation_Form: tabular digital data Publication_Information: Publication_Place: Charleston, SC Publisher: NOAA Office for Coastal Management (NOAA/OCM) Online_Linkage: https://www.fisheries.noaa.gov/inport/item/50081 Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1061 Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20090203 Ending_Date: 20090423 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: LA_MS_TX_2009 Source_Contribution: The bare-earth lidar point cloud data in LAS format were used to calculate beach slope using methods described in the process steps. The point data were downloaded using the cart feature in the appropriate UTM zone projection with NAD83 horizontal datum and NAVD88 vertical datum (meters), in the most recent Geoid. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 20100101 Title: 2010 USGS/NASA Experimental Advanced Airborne Research Lidar (EAARL): Chandeleur Islands, Louisiana (Bare-Earth) Geospatial_Data_Presentation_Form: tabular digital data Publication_Information: Publication_Place: Charleston,SC Publisher: NOAA Office for Coastal Management (NOAA/OCM) Online_Linkage: https://www.fisheries.noaa.gov/inport/item/50116 Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1066 Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20100303 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: LAch_2010 Source_Contribution: The bare-earth lidar point cloud data in LAS format were used to calculate beach slope using methods described in the process steps. The point data were downloaded using the cart feature in the appropriate UTM zone projection with NAD83 horizontal datum and NAVD88 vertical datum (meters), in the most recent Geoid. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 20110426 Title: 2010 USACE NCMP Topo Lidar: Gulf Coast (LA, MS) Geospatial_Data_Presentation_Form: tabular digital data Publication_Information: Publication_Place: Charleston,SC Publisher: NOAA Office for Coastal Management (NOAA/OCM) Online_Linkage: https://www.fisheries.noaa.gov/inport/item/50086 Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1065 Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20100409 Ending_Date: 20100426 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: LA_2010 Source_Contribution: The bare-earth lidar point cloud data in LAS format were used to calculate beach slope using methods described in the process steps. The point data were downloaded using the cart feature in the appropriate UTM zone projection with NAD83 horizontal datum and NAVD88 vertical datum (meters), in the most recent Geoid. Source_Information: Source_Citation: Citation_Information: Originator: NOAA Office for Coastal Management (NOAA/OCM) Publication_Date: 20110716 Title: 2009 US Army Corps of Engineers (USACE) Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBTCX) Topographic Lidar: South Texas Coast Geospatial_Data_Presentation_Form: tabular digital data Publication_Information: Publication_Place: Charleston, SC Publisher: NOAA Office for Coastal Management (NOAA/OCM) Online_Linkage: https://www.fisheries.noaa.gov/inport/item/50082 Online_Linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1063 Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20090203 Ending_Date: 20090423 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: TX_2009 Source_Contribution: The bare-earth lidar point cloud data in LAS format were used to calculate beach slope using methods described in the process steps. The point data were downloaded using the cart feature in the appropriate UTM zone projection with NAD83 horizontal datum and NAVD88 vertical datum (meters), in the most recent Geoid. Process_Step: Process_Description: For each state/region, a coast-following reference baseline was digitized in UTM using Google Earth. The baselines sometimes continued across inlets, rocky headlands, or other areas where shorelines were not extracted. These baselines were loaded into Matlab (version R2007a), and equally-spaced points were defined along the lines at a 20-meter spacing. Transect lines perpendicular the baselines were calculated at each of these points. The transects are defined by their origin point (the point on the baseline), their slope, and the y-intercept using the formula: y = m*x + b, where m is the slope, b is the y intercept, x is the easting of the transect origin and y is the northing of the transect origin. This process step was completed by Amy S. Farris. Process_Date: 2007 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Amy S. Farris Contact_Organization: U.S. Geological Survey Contact_Position: Oceanographer Contact_Address: Address_Type: mailing address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543 Country: US Contact_Voice_Telephone: 508-548-8700 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: afarris@usgs.gov Process_Step: Process_Description: The reference baseline and transects were merged for all states/regions. The transect origins were converted to a geographic coordinate system. However, since the transect lines are defined in UTM (NAD83) and cannot be expressed in geographic, the transect origins are also provided in UTM. The final reference line data matrix has one row for each transect and each row contains the following information: state, region, transect number, latitude and longitude of the transect origin, easting and northing of the transect origin, slope of the transect (m in the formula y=m*x+b) , y-intercept (b in the formula y=m*x+b), mean high water (MHW) elevation (meters above NAVD88), UTM zone. The elevation of MHW was determined from Weber and others (2005). We do not use a continuously varying MHW, but rather use one number for a long section of coast. This value is within 15 cm of the 'true' value of MHW. The final reference line data matrix was output as both a .csv and a shapefile. All points on the baseline are given, even if no shorelines were found on the transect associated with that point. All work was done in Matlab (version R2023a) by Amy S. Farris. Process_Date: 2023 Process_Step: Process_Description: A transect-based method described in Farris and others (2018) was used to estimate the slope of the foreshore of the beach using Matlab (version R2023a). This method utilized the transects created in the first process step. All lidar data points within 1 meter (in the alongshore direction) of each transect were associated with that transect. All processing was done on each 2-meter wide transect, working on a single transect at a time. For each transect, points on the foreshore were identified and a linear regression was fit through them. Foreshore beach slope was defined as the slope of the regression line. The regression was evaluated at the elevation of mean high water (MHW) to yield the location of the shoreline. See second process step for information about how the height of mean high water was determined. The shoreline position on each transect has an estimated horizontal uncertainty associated with it. This uncertainty includes four components: 1) the 95% confidence interval on the linear regression estimate of the shoreline position; 2) the vertical error of the raw lidar data as reported in the lidar data’s metadata; 3) a +/- 15 cm vertical error in our chosen value of MHW, and; 4) the uncertainty due to extrapolation (if the shoreline was determined using extrapolation). These four components of uncertainty were added in quadrature to yield a total error for each shoreline point. This step was completed by several people: Kathryn M. Weber, Marie K. Bartlett and Amy S. Farris (all at USGS, Woods Hole). Process_Date: 2023 Process_Step: Process_Description: The slope data for all surveys for all states were merged into a single data matrix in Matlab (version R2023a). For each survey, the following data were preserved for each transect and added as a row to the matrix of the data: state, region, year and month of survey, transect number, latitude and longitude of shoreline position, foreshore beach slope, distance from shoreline to the transect origin, and shoreline uncertainty. The final slope data matrix was output as both a .csv file and a shapefile. This step was completed by Amy S. Farris. Process_Date: 2023 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: point Point_and_Vector_Object_Count: 110331 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.0197704219 Longitude_Resolution: 0.0239377492 Geographic_Coordinate_Units: Decimal seconds Geodetic_Model: Horizontal_Datum_Name: North_American_Datum_1983 Ellipsoid_Name: GRS 1980 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257222101 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: slopeData_GulfCoast.shp Attribute Table Entity_Type_Definition: The point shapefile file contains estimates of the foreshore beach slope at the shoreline position along the cross-shore transects. A .csv file containing the same fields (except for "FID" and "Shape") is also provided. Entity_Type_Definition_Source: 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: Shape type. Attribute: Attribute_Label: State Attribute_Definition: Two letter state designation Attribute_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: TX Enumerated_Domain_Value_Definition: Texas Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: LA Enumerated_Domain_Value_Definition: Louisiana Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: AL Enumerated_Domain_Value_Definition: Alabama Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: FL Enumerated_Domain_Value_Definition: Florida Enumerated_Domain_Value_Definition_Source: USGS Attribute: Attribute_Label: Region Attribute_Definition: Two letter region designation Attribute_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: na Enumerated_Domain_Value_Definition: no region for this state Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: ph Enumerated_Domain_Value_Definition: Panhandle of Florida Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: wc Enumerated_Domain_Value_Definition: West Coast of Florida and West Coast of Louisiana, from Texas to Marsh Island Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: ch Enumerated_Domain_Value_Definition: Chandeleur Islands, LA Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: bi Enumerated_Domain_Value_Definition: Barrier islands south of New Orleans Enumerated_Domain_Value_Definition_Source: USGS Attribute: Attribute_Label: Year Attribute_Definition: year of data collection, as YYYY Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 2001 Range_Domain_Maximum: 2018 Attribute: Attribute_Label: Month Attribute_Definition: Approximate month of data collection; as MM. Occasionally, some lidar surveys extended over multiple months. In these cases the month with the most data was listed. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 1 Range_Domain_Maximum: 12 Attribute: Attribute_Label: TransNum Attribute_Definition: Transect number. Transect numbers are not unique. They restart from 0 for each state, or if the state is divided into regions, for each region. Numbers increase roughly from south to north and/or west to east. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0 Range_Domain_Maximum: 30511 Attribute_Units_of_Measure: none Attribute: Attribute_Label: Latitude Attribute_Definition: Latitude of calculated shoreline position. This is the location at which beach slope was estimated. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 25.847 Range_Domain_Maximum: 30.39715 Attribute_Units_of_Measure: degrees Attribute: Attribute_Label: Longitude Attribute_Definition: Longitude of calculated shoreline position. This is the location at which beach slope was estimated. All longitude values are west. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -97.3793 Range_Domain_Maximum: -81.6822 Attribute_Units_of_Measure: degrees Attribute: Attribute_Label: Slope Attribute_Definition: Slope of the beach foreshore Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.446 Range_Domain_Maximum: 29.121 Attribute_Units_of_Measure: degrees Attribute: Attribute_Label: ShoreDist Attribute_Definition: Distance between the calculated shoreline position and transect origin (at the reference baseline). Positive values denote a shoreline position seaward of the baseline, negative values denote a position landward of the baseline. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -12715.37 Range_Domain_Maximum: 1173.79 Attribute_Units_of_Measure: meters Attribute: Attribute_Label: ShoreUncy Attribute_Definition: Estimated uncertainty of the shoreline position. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0 Range_Domain_Maximum: 19.992 Attribute_Units_of_Measure: meters Detailed_Description: Entity_Type: Entity_Type_Label: referenceLine_GulfCoast.shp Attribute Table Entity_Type_Definition: The point shapefile file includes information about the reference baseline, cross-shore transects, and mean high water (MHW) values used to calculate shorelines for the Gulf Coast of the United States. A .csv file containing the same fields (except for "FID" and "Shape") is also included. Entity_Type_Definition_Source: 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: Shape type. Attribute: Attribute_Label: State Attribute_Definition: Two letter state abbreviation Attribute_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: TX Enumerated_Domain_Value_Definition: Texas Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: LA Enumerated_Domain_Value_Definition: Louisiana Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: MS Enumerated_Domain_Value_Definition: Mississippi Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: AL Enumerated_Domain_Value_Definition: Alabama Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: FL Enumerated_Domain_Value_Definition: Florida Enumerated_Domain_Value_Definition_Source: USGS Attribute: Attribute_Label: Region Attribute_Definition: Two letter region designation Attribute_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: na Enumerated_Domain_Value_Definition: no region for this state Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: ph Enumerated_Domain_Value_Definition: Panhandle of Florida Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: wc Enumerated_Domain_Value_Definition: West Coast of Florida and West Coast of Louisiana, from Texas to Marsh Island Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: ch Enumerated_Domain_Value_Definition: Chandeleur Islands, LA Enumerated_Domain_Value_Definition_Source: USGS Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: bi Enumerated_Domain_Value_Definition: Barrier islands south of New Orleans Enumerated_Domain_Value_Definition_Source: USGS Attribute: Attribute_Label: TransNum Attribute_Definition: Transect number. Transect numbers are not unique. They restart from 0 for each state, or if the state is divided into regions, for each region. Numbers increase roughly from south to north and/or west to east. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0 Range_Domain_Maximum: 30623 Attribute: Attribute_Label: Latitude Attribute_Definition: Latitude of transect origin. (NAD83) Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 25.84474 Range_Domain_Maximum: 30.39645 Attribute_Units_of_Measure: degrees Attribute: Attribute_Label: Longitude Attribute_Definition: Longitude of transect origin. Negative indicates west longitude. (NAD83) Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -97.3789 Range_Domain_Maximum: -81.6623 Attribute_Units_of_Measure: degrees Attribute: Attribute_Label: X_UTM Attribute_Definition: Easting of transect origin (UTM, NAD83, meters) Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 204033.3 Range_Domain_Maximum: 793421.2 Attribute: Attribute_Label: Y_UTM Attribute_Definition: Northing of transect origin (UTM, NAD83, meters) Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 2858665.8 Range_Domain_Maximum: 3362775.7 Attribute: Attribute_Label: TransSlope Attribute_Definition: Slope of the transect line, unitless. Defined using the formula y = m*x + b, where m is the slope, x is the easting of the transect origin, y is the northing of the transect origin and b is the y-intercept. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -301.936 Range_Domain_Maximum: 181.157 Attribute: Attribute_Label: Y_intercept Attribute_Definition: Y-intercept of the transect line, defined using the formula y = m*x + b, where b is the y-intercept, m is the slope, x is the easting of the transect origin, and y is the northing of the transect origin. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -74667006.9 Range_Domain_Maximum: 199277895.7 Attribute: Attribute_Label: MHW Attribute_Definition: The elevation of mean high water (relative to NAVD88) used to calculate the location of the shoreline. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.09 Range_Domain_Maximum: 0.37 Attribute_Units_of_Measure: meters Attribute: Attribute_Label: UTMzone Attribute_Definition: UTM zone in which the transect is located Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 14 Range_Domain_Maximum: 17 Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey - 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 point shapefile and the tabular data for the foreshore beach slope (slopeData_GulfCoast.shp and slopeData_GulfCoast.csv), the point shapefile and the tabular data for the reference line and transects (referenceLine_GulfCoast.shp and referenceLine_GulfCoast.csv), browse graphic (slope_BrowseGraphic.png), and the FGDC CSDGM metadata in XML 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 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: created by Matlab ver 2023a Format_Specification: Esri point shapefile Format_Information_Content: Dataset contains the shapefile (and its components), .csv file, browse graphic, and CSDGM metadata. Transfer_Size: 26 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://www.sciencebase.gov/catalog/file/get/66fae79fd34e6d68f514c592 Network_Resource_Name: https://www.sciencebase.gov/catalog/item/66fae79fd34e6d68f514c592 Network_Resource_Name: https://doi.org/10.5066/P14JUVPT Access_Instructions: The first link downloads all the files on the dataset landing page. The second link is to the dataset landing page where individual files can be viewed and downloaded. The third link is to the data release main landing page. Digital_Form: Digital_Transfer_Information: Format_Name: CSV Format_Version_Number: created by Matlab ver 2023a Format_Information_Content: Dataset contains the shapefile (and its components), .csv file, browse graphic, and CSDGM metadata. Transfer_Size: 8 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://www.sciencebase.gov/catalog/file/get/66fae79fd34e6d68f514c592 Network_Resource_Name: https://www.sciencebase.gov/catalog/item/66fae79fd34e6d68f514c592 Network_Resource_Name: https://doi.org/10.5066/P14JUVPT Access_Instructions: The first link downloads all the files on the dataset landing page. The second link is to the dataset landing page where individual files can be viewed and downloaded. The third link is to the data release main landing page. Fees: None Technical_Prerequisites: These data are available in point shapefile format. The user must have software to read and process the data components of a shapefile. Metadata_Reference_Information: Metadata_Date: 20241203 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Amy S. Farris Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543 Country: US 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 Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998