U.S. Geological Survey 2017 1 vector digital data data release DOI:10.5066/F78P5XNK Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Geology Program https://doi.org/10.5066/F78P5XNK https://www.sciencebase.gov/catalog/item/582ca4b0e4b04d580bd37906 https://www.sciencebase.gov/catalog/file/get/582ca4b0e4b04d580bd37906 E.A. Himmelstoss M.G. Kratzmann E.R. Thieler 2017 1 data release DOI:10.5066/F78P5XNK Reston, VA U.S. Geological Survey https://doi.org/10.5066/F78P5XNK https://www.sciencebase.gov/catalog/item/58055db4e4b0824b2d1c1ee2 Sandy ocean beaches are a popular recreational destination, often surrounded by communities containing valuable real estate. Development is on the rise despite the fact that coastal infrastructure is subjected to flooding and erosion. As a result, there is an increased demand for accurate information regarding past and present shoreline changes. To meet these national needs, the Coastal and Marine Geology Program of the U.S. Geological Survey (USGS) is compiling existing reliable historical shoreline data along open-ocean sandy shores of the conterminous United States and parts of Alaska and Hawaii under the National Assessment of Shoreline Change project. There is no widely accepted standard for analyzing shoreline change. Existing shoreline data measurements and rate calculation methods vary from study to study and prevent combining results into state-wide or regional assessments. The impetus behind the National Assessment project was to develop a standardized method of measuring changes in shoreline position that is consistent from coast to coast. The goal was to facilitate the process of periodically and systematically updating the results in an internally consistent manner. This dataset consists of long-term (~150 years) shoreline change rates for the Louisiana coastal region from the Chandeleur Islands to Raccoon Point, on Isles Dernieres at the mouth of Caillou Bay. Rate calculations were computed within a GIS using the Digital Shoreline Analysis System (DSAS) version 4.3, an ArcGIS extension developed by the U.S. Geological Survey. Long-term rates of shoreline change were calculated using a linear regression rate based on available shoreline data for a minimum 50-year period. A reference baseline was used as the originating point for the orthogonal transects cast by the DSAS software. The transects intersect each shoreline establishing measurement points, which are then used to calculate long-term rates. 2017 publication date Complete None planned -90.959018 -88.809440 30.061303 29.027118 USGS Metadata Identifier USGS:582ca4b0e4b04d580bd37906 None Long-Term Shoreline Change Rate Shoreline Historic Shoreline Erosion Accretion Linear Regression Rate Transect Digital Shoreline Analysis System DSAS U.S. Geological Survey USGS Coastal and Marine Geology Program CMGP Woods Hole Coastal and Marine Science Center WHCMSC National Assessment of Shoreline Change Project ISO 19115 Topic Category oceans environment geoscientificInformation Marine Realms Information Bank (MRIB) Keywords effects of coastal change coastal processes shoreline accretion shoreline erosion USGS Thesaurus coastal processes erosion shoreline accretion None Louisiana LA Chandeleur Islands Breton National Wildlife Refuge Breton Islands Pelican Island Lanaux Island Grand Terre Islands Grand Isle East Timbalier Island Isles Dernieres Gulf of Mexico United States North America None 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. U.S. Geological Survey E.A. Himmelstoss mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA 508-548-8700 508-457-2310 ehimmelstoss@usgs.gov Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.2.2.3552 Robert A. Morton Tara L. Miller Laura J. Moore 2004 Open-File Report 2004-1043 Reston, VA U.S. Geological Survey https://pubs.usgs.gov/of/2004/1043/ E.R. Thieler E.A. Himmelstoss J.L. Zichichi A. Ergul 2009 Open-File Report 2008-1278 Reston, VA U.S. Geological Survey Current version of software at time of use was 4.3 https://woodshole.er.usgs.gov/project-pages/DSAS/version4/ https://woodshole.er.usgs.gov/project-pages/DSAS/ E.A. Himmelstoss M.G. Kratzmann E.R. Thieler 2017 Open-File Report 2017-1015 Reston, VA U.S. Geological Survey https://doi.org/10.3133/ofr20171015 The attributes of this dataset are based on the field requirements of the Digital Shoreline Analysis System and were automatically generated by the software during the generation of the transect layer or during the calculation of shoreline change rates performed by the software. These data were generated using DSAS v4.3, an automated software program which does not perform checks for fidelity of the input features. The transects were visually inspected and sometimes manually adjusted within a standard ArcMap edit session to adjust the position at which an individual transect intersected the shorelines. This dataset contains the transects automatically generated by the DSAS software application that were used to calculate long-term shoreline change rates for the region. Additional transects may have been generated but did not intersect the minimum requirement of three shorelines, one of which must be the modern (lidar-derived or 1990s) shoreline, to calculate long-term rates for a minimum 50-year period. Transect features generated using DSAS v4.3 in ArcMap v10.2. Parameters Used: baseline layer=LA_baseline, baseline group field=NULL, transect spacing=50 meters, transect length=5000 meters, cast direction=AUTO-DETECT, baseline location=offshore, cast method=smoothed, smoothing distance=9000 meters, flip baselines=not selected. For additional details on these parameters, please see the DSAS help file distributed with the DSAS software, or visit the website at: https://woodshole.er.usgs.gov/project-pages/DSAS/version4/ This process step and all subsequent process steps were performed by the same person: M.G. Kratzmann. 20150825 M.G. Kratzmann U.S. Geological Survey mailing address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA 508-548-8700 508-457-2310 mkratzmann@usgs.gov Some transects were manually edited for length, moved, or deleted in an edit session using standard editing tools in ArcMap v10.2. 20150825 Rate calculations performed using DSAS v4.3 in ArcMap v10.2 where at least three shorelines were present. Shoreline uncertainty table added to ArcMap project (LA_shorelines_uncertainty.dbf) and used by DSAS to apply bias-correction to distance measurements established by transects. Parameters Used: shoreline layer=LA_shorelines, shoreline date field=Date_, shoreline uncertainty field name=Uncy, the default uncertainty=10.8 meters, shoreline intersection parameters=closest, stats calculations=[Linear Regression Rate (LRR)], shoreline threshold=3, confidence interval=90%, Output rate table name=LA_LT_transects_rates_20150825_142117. 20150825 Shoreline rates table (LA_LT_transects_rates_20150825_142117.dbf) was joined to the transect feature class in ArcMap v10.2 by right-clicking on the transect layer > joins and relates > join > join attributes from a table. Parameters: join field - Object ID; table to join - LA_LT_transects_rates_20150825_142117; field in table: TransectID; join options - keep only matching records. 20150825 The joined transect feature class was exported to a shapefile in ArcMap v10.2 by right-clicking the transect layer > data > export data, permanently linking the joined rate fields to the transect attribute table. 20150825 Any transects that did not cross the modern (lidar-derived or 1990s) shoreline were deleted using standard editing tools in ArcMap v10.2. 20150825 A quality check was performed on any transects that intersected only three shorelines to be sure the 50-year span for long term rates was covered and that a modern (lidar-derived or 1990s) shoreline was present. A frequency table was created in ArcToobox v10.2 > Analysis Tools > Statistics > Frequency. The output frequency table was used to identify any transects with a count value of 3. If the long term rate criteria were not met, the transect was deleted. 20150825 The exported transect shapefile was projected in Esri's ArcToolbox (v10.2) > Data Management Tools > Projections and Transformations > Project. Parameters: input projection - NAD 1983 State Plane Louisiana South FIPS 1702 (Meters); output projection- geographic coordinates (WGS 84); transformation = NAD_1983_To_WGS_1984_1. 20150827 Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. 20170825 U.S. Geological Survey Alan O. Allwardt Contractor -- Information Specialist mailing and physical address

2885 Mission Street

Santa Cruz CA 95060 831-460-7551 831-427-4748 aallwardt@usgs.gov Added keywords section with USGS persistent identifier as theme keyword. Process performed on 20200810. The metadata title was modified to move the location name to the beginning of the title to account for the alphabetical listing of the individual records when ScienceBase migrates the data release to a new platform and "flattens" the data release structure (20260302). 20260302 U.S. Geological Survey VeeAnn A. Cross Marine Geologist Mailing and Physical

384 Woods Hole Road

Woods Hole MA 02543-1598 508-548-8700 x2251 508-457-2310 vatnipp@usgs.gov Vector String 3451 0.000001 0.000001 Decimal degrees D_WGS_1984 WGS_1984 6378137.000000 298.257224 LA_LT_rates Transects were automatically generated by DSAS at a 90 degree angle to the user-specified baseline using a smoothing algorithm to maintain roughly parallel transects that are orthogonal with respect to the baseline. U.S. Geological Survey FID Internal feature number. Esri Sequential unique whole numbers that are automatically generated. Shape Feature geometry. Esri Coordinates defining the features. OBJECTID Internal feature number generated for each row of the transect attribute table when stored as a feature class in a geodatabase. This value is the common attribute field when joining to the TransectID value in long-term results output table calculated by DSAS. U.S. Geological Survey Sequential unique whole numbers that are automatically generated. BaselineID Unique identification number of the baseline segment. If BaselineID=0 no transects will be generated. Used by DSAS to determine transect ordering alongshore if multiple baseline segments exist. U.S. Geological Survey 1 unlimited TransOrder Assigned by DSAS based on ordering of transects along the baseline. Used to allow user to sort transect data along the baseline from baseline start to baseline end. U.S. Geological Survey 0 unlimited ProcTime Assigned by DSAS automatically to record the date and time a transect was processed. U.S. Geological Survey no value (when transect was manually created by user) unlimited (values based on time and date of automatic generation) Autogen Assigned by DSAS to indicate whether or not a transect was automatically created by DSAS (1= transect was auto generated by DSAS; blank or 0=transect was not auto-generated). U.S. Geological Survey blank or 0 1 StartX Assigned by DSAS automatically to record the X coordinate of the beginning of the transect in meter units. If a transect position has been adjusted during the editing process, the coordinate in the attribute table is not updated automatically. This field was manually updated using Data East XTools v.10.2 to reflect the new position of any adjusted transects. U.S. Geological Survey Values based on data set extent. StartY Assigned by DSAS automatically to record the Y coordinate of the beginning of the transect in meter units. If a transect position has been adjusted during the editing process, the coordinate in the attribute table is not updated automatically. This field was manually updated using Data East XTools v.10.2 to reflect the new position of any adjusted transects. U.S. Geological Survey Values based on data set extent. EndX Assigned by DSAS automatically to record the X coordinate of the end of the transect in meter units. If a transect position has been adjusted during the editing process, the coordinate in the attribute table is not updated automatically. This field was manually updated using Data East XTools v.10.2 to reflect the new position of any adjusted transects. U.S. Geological Survey Values based on data set extent. EndY Assigned by DSAS automatically to record the Y coordinate of the end of the transect in meter units. If a transect position has been adjusted during the editing process, the coordinate in the attribute table is not updated automatically. This field was manually updated using Data East XTools v.10.2 to reflect the new position of any adjusted transects. U.S. Geological Survey Values based on data set extent. Azimuth Assigned by DSAS to record the azimuth of the transect measure in degrees clockwise from North. If a transect position has been adjusted during the editing process, the azimuth value in the attribute table is not updated automatically. This field was manually updated using a python script to reflect the new azimuth of any adjusted transects. U.S. Geological Survey 0 360 degrees SHAPE_Leng Length of feature in meter units (NAD 1983 State Plane Louisiana South FIPS 1702 (Meters)). Esri 1388.401113 5000.000004 meters TransectId Same value as ObjectID. Used as a permanent and unique identification number for each transect in the output rates table calculated by DSAS. This attribute was used as the common field when joining the rates table (.dbf) to the transect feature class in a geodatabase. U.S. Geological Survey Positive real numbers that are automatically generated. LRR A linear regression rate-of-change statistic was calculated by fitting a least-squares regression line to all shoreline points for a particular transect. The best-fit regression line is placed so that the sum of the squared residuals (determined by squaring the offset distance of each data point from the regression line and adding the squared residuals together) is minimized. The linear regression rate is the slope of the line. The rate is reported in meters per year with positive values indicating accretion and negative values indicating erosion. U.S. Geological Survey -39.62 19.45 meters per year LR2 The R-squared statistic, or coefficient of determination, is the percentage of variance in the data that is explained by a regression. It is a dimensionless index that ranges from 1.0 to 0.0 and measures how successfully the best-fit line accounts for variation in the data. The smaller the variability of the residual values around the regression line relative to the overall variability, the better the prediction (and closer the R-squared value is to 1.0). U.S. Geological Survey 0 1 LSE The predicted (or estimated) values of y (the distance from baseline in meters) are computed for each shoreline point by using the values of x (the shoreline date) and solving the equation for the best-fit regression line (y=mx+b). The standard error is also called the standard deviation. U.S. Geological Survey 0.3 1229.89 meters LCI90 The standard error of the slope with confidence interval describes the uncertainty of the reported rate. The LRR rates are determined by a best-fit regression line for the shoreline data at each transect. The slope of this line is the reported rate of change (in meters/year). The confidence interval (LCI) is calculated by multiplying the standard error (also called the standard deviation) of the slope by the two-tailed test statistic at the user-specified 90 percent confidence. This value is often reported in conjunction with the slope to describe the confidence of the reported rate. For example: LRR = 1.2 LCI90 = 0.7 could be reported as a rate of 1.2 (+/-) 0.7 meters/year. U.S. Geological Survey 0.019 83.355 meters The entity and attribute information provided here describes the tabular data associated with the dataset. Please review the individual attribute descriptions for detailed information. All calculations for length are in meter units and were based on the NAD 1983 State Plane Louisiana South FIPS 1702 (Meters) projection. U.S. Geological Survey U.S. Geological Survey mailing and physical address

Denver Federal Center

Building 810

MS 302

Denver CO 80225 USA 1-888-275-8747 sciencebase@usgs.gov 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. Shapefile ArcGIS 10.2 Esri polyline shapefile These files (.cpg, .dbf, .prj, .sbn, .sbx, .shp, .shp.xml, 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 compliant metadata. no compression applied 1.2 https://www.sciencebase.gov/catalog/file/get/582ca4b0e4b04d580bd37906 https://www.sciencebase.gov/catalog/item/582ca4b0e4b04d580bd37906 https://www.sciencebase.gov/catalog/item/58055db4e4b0824b2d1c1ee2 https://doi.org/10.5066/F78P5XNK The first link downloads the contents of the data page as a zip file, the second link is to the landing page of the data, the third and fourth links are to the main landing page of the data release. None These data are available in a polyline shapefile format. The user must have software to read and process the data components of a shapefile. 20260302 E.A. Himmelstoss U.S. Geological Survey mailing address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA 508-548-8700 x2262 508-547-2310 whsc_data_contact@usgs.gov The metadata contact email address is a generic address in the event the person is no longer with USGS. (updated on 20240319) FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 local time