Noreen A. Buster Owen T. Brenner James G. Flocks 20171121 raster digital data U.S. Geological Survey Data Release doi:10.5066/F7028QFV St. Petersburg, FL U.S. Geological Survey https://doi.org/10.5066/F7028QFV To characterize coastal change, historical maps and complementary records were compiled including: topographic sheets (T-sheets), hydrographic sheets (H-sheets, smooth sheets), shorelines, and bathymetric soundings surrounding the Mississippi (MS) barrier islands over several time periods (1916-1920, 2008-2009 and 2016). One goal of this work was to create a time-series of bathymetric change maps around the islands. Data sets include 1916 through 1920 soundings collected by the United States Coast and Geodetic Survey as downloaded H-sheets and some digitized soundings from the National Oceanic and Atmospheric Administration (NOAA), 2008 to 2009 soundings collected by the United States Geological Survey St. Petersburg and Woods Hole Coastal and Marine Science Centers (USGS SPCMSC and WHCMSC, respectively), and 2016 soundings collected by the USGS SPCMSC in the nearshore environment of Ship, Horn, and Petit Bois Islands. This USGS data release includes three interpolated bathymetric change maps created by comparing the 1916 to 1920, 2008 to 2009, and 2016 bathymetry data; however, this metadata file pertains to the bathymetric change digital elevation model (DEM) observed between the 1916-1920 and 2008-2009 bathymetry (2008to2009minus1916to1920_MS_NAD83NAVD88g12B_50m.tif). This work was completed in cooperation with the United States Army Corps of Engineers (Mobile, Alabama) and the National Park Service as part of the Mississippi Coastal Improvements Program (MsCIP). The purpose of this effort was to create bathymetric grids and bathymetric change maps around the MS barrier islands to broadly characterize subaqueous morphologic change both spatially and temporally. Elevation XYZ data used to create the 1916 to 1920 and 2008 to 2009 DEM are included in this USGS data release. The 1916 to 2009 elevation (z) values were adjusted to account for sea-level rise, using the NOAA tide gauge at Pensacola, FL. Within ArcGIS 10.4.1, XYZ soundings for 1916-1920 and 2008-2009 were used to create Triangular Irregular Network (TIN) surfaces, individual TIN surfaces were later utilized to create a time-series of 50-m bathymetric rasters. A common snap raster was used to create these DEMs to maximize accuracy of subsequent bathymetric change map calculation. Bathymetric change maps were created using the 'Raster Calculator' and subtracting the one DEM from another. All spatial files provided in this data release are referenced to the Universal Transverse Mercator (UTM) North American Datum (NAD83) horizontal datum and North American Vertical Datum of 1988 (NAVD88) GEOID12B. 1916 1920 2008 2009 ground condition complete None planned -89.001807 -88.320014 30.269508 30.175643 USGS Metadata Identifier USGS:42de54cd-7e4d-42df-b43a-4e3cd5b93ce9 ISO 19115 Topic Category oceans elevation location geoscientificInformation imageryBaseMapsEarthCover USGS Thesaurus marine geology geophysics bathymetry digital elevation models ocean characteristics ocean processes None soundings hydrography geophysical seafloor mapping historical NOAA National Oceanic and Atmospheric Administration U.S. Geological Survey USGS Coastal and Marine Geology Program CMGP St. Petersburg Coastal and Marine Science Center SPCMSC coastal location Geographic Names Information System (GNIS) Mississippi Alabama Ship Island Horn Island Petit Bois Island Dauphin Island Mississippi Sound Oregon Geospatial Enterprise Office (GEO) sea surface epipelagic None 1916-1920 2008-2009 None Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. The U.S. Geological Survey requests to be acknowledged as originator of these data in future products or derivative research. Noreen A. Buster U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center mailing and physical

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St. Petersburg FL 33701 USA (727) 502-8000 nbuster@usgs.gov U.S. Geological Survey, Coastal and Marine Geology Program, St. Petersburg Coastal and Marine Science Center Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.4.1 Noreen A. Buster Robert A. Morton 20110404 U.S. Geological Survey Scientific Investigations Map SIM 3154 St. Petersburg, FL St. Petersburg Coastal and Marine Science Center https://pubs.usgs.gov/sim/3154/ Nancy T. DeWitt James G. Flocks Elizabeth A. Pendleton Mark E. Hansen B.J. Reynolds Kyle W. Kelso Dana S. Wiese Charles R. Worley 2012 U.S. Geological Survey Data Series DS 675 St. Petersburg, FL St. Petersburg Coastal and Marine Science Center https://pubs.usgs.gov/ds/675/ Nancy T. DeWitt Chelsea A. Stalk Jake J. Fredericks James G. Flocks Kyle W. Kelso Andrew S. Farmer Thomas M. Tuten Noreen A. Buster 2017 U.S. Geological Survey Data Release DR F7B8571Q St. Petersburg, FL St. Petersburg Coastal and Marine Science Center https://doi.org/10.5066/F7B8571Q Kathryn M. Weber Jeffrey H. List Karen L.M. Morgan 2005 U.S. Geological Survey Open-File Report OFR 2005-1027 Woods Hole, MA Woods Hole Coastal and Marine Science Center https://pubs.usgs.gov/of/2005/1027/ The accuracy of this bathymetric change DEM is entirely dependent upon the accuracy of the two DEM surfaces (1916-1920 and 2016) used to calculate the elevation change it represents. DEM surfaces were created using a common snap raster to ensure direct pixel value comparison in quantifying bathymetric change. The accuracy of the 1916-1920 DEM is directly linked to the accuracy of the XYZ point data on which it is based (Buster and Morton, 2011). These datasets were from multiple research cruises spanning over 4 years (1916-1920) and were collected following variable methodologies; therefore, they are not internally consistent. The accuracy of the 2008-2009 DEM is directly linked to the accuracy of the XYZ point data on which it is based (Dewitt and others, 2017). As reported (Dewitt and others, 2017) a GPS base station, spaced approximately 15 km from the survey area, collected continuous data for GPS post-processing corrections. All static base station sessions were run through the On-Line Positioning User Service (OPUS) and resulting corrections produced +/-3.3 cm or less accuracy in the vertical component. Additionally, vertical datums associated with XYZ data have been recalculated (using VDatum and a NOAA tide gauge at Pensacola, FL) to allow for time series comparisons and this process introduces uncertainties into the data. Uncertainties are also introduced in interpolating DEM surfaces within Esri ArcGIS. The DEMs have not been independently verified for accuracy. For full accuracy and error information please see Buster and Morton, (2011), Dewitt and others (2012 and 2017), and metadata associated with each bathymetric DEM within this data release. This dataset includes the post-processed bathymetric data (XYZ) presented as an interpolated DEM representing bathymetric change occurring between 1916-1920 and 2008-2009. The source data for the DEM was collected during multiple bathymetry surveys from 1916-1920 and 2008-2009 near Ship, Horn, and Petit Bois islands in Mississippi. All spatial files provided in this data release are referenced in NAD83 UTM 16N (meters) and NAVD88 GEOID12B. A portion of the source data (1916-1920) is historical and; therefore, not complete in its coverage. The source data was used to create DEM surfaces that best represent the historical soundings and were used to calculate bathymetric change, all while using best practice methods to keep the data as accurate as possible. See above accuracy report information for additional details. The horizontal accuracy of this bathymetric change map is entirely linked to the accuracy of the DEMs used to create it, 1916-1920 and 2008-2009. No formal positional accuracy tests were conducted for the 1916-1920 XYZ data; however, Buster and Morton (2011) estimate horizontal accuracy values less than 20 and 29 meters for the historic T-sheets and H-sheets that were used to create the original 1916-1920 XYZ bathymetric dataset. Dewitt and others (2012) report a horizontal accuracy value of +/- 10 to 13 cm for the orginal 2008-2009 bathymetric dataset used to create the 2008-2009 DEM. Additional sources of error include 1) vertical datum conversion using NOAA's Vdatum software and, 2) creation of a triangulated Irregular TIN and interpolation of the DEM raster, with 50-m cell size and using nearest neighbor interpolation, within ArcGIS (version 10.4.1). The vertical accuracy of this bathymetric change map is entirely linked to the accuracy of the 1916-1920 and 2008-2009 DEMs (1916_1920_MS_NAD83NAVD88g12B_50m.tif and 2008_2009_MS_NAD83NAVD88g12B_50m.tif). Likely due to the age of the 1916-1920 dataset and variable survey collection methods, no formal vertical accuracy tests were conducted in association with the original publication of the 1916-1920 bathymetric dataset (Buster and Morton, 2011). Dewitt and others (2012) report a vertical accuracy value of +/- 3.3 centimeters for the 20108-2009 XYZ bathymetric dataset used to create the 2008-2009 DEM. Subsequent data processing steps, specifically converting vertical datum of the XYZ data and interpolating DEM surfaces within Esri ArcGIS, introduce additional sources of uncertainty, that have not been fully assessed. Using Esri ArcGIS (version 10.4.1), elevation pixel values from the 1916-1920 bathymetry DEM (1916_1920_MS_NAD83NAVD88g12B_50m.tif) were subtracted from co-located elevation pixel values of the 2008-2009 bathymetry DEM (2008_2009_MS_NAD83NAVD88g12B_50m.tif) using the 'Raster Calculator' tool. The resulting bathymetric change DEM was saved as a TIFF raster file (.tif) and associated TIFF worldfile (.tfw). 201707 Noreen A. Buster U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center Geologist mailing

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St. Petersburg FL 33701 USA (727) 502-8000 nbuster@usgs.gov Added keywords section with USGS persistent identifier as theme keyword. 20201013 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 Raster Grid Cell 189 1310 Universal Transverse Mercator 16 0.999600 -87.000000 0.000000 500000.000000 0.000000 row and column 50 50 meters North American Datum 1983 Geodetic Reference System 80 6378137.000000 298.257222101 North American Vertical Datum 1988 GEOID12B 0.0001 meters Attribute values Noreen A. Buster U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center mailing and physical

600 4th Street South

St. Petersburg FL 33701 USA (727) 502-8000 nbuster@usgs.gov 2008to2009minus1916to1920_MS_NAD83NAVD88g12B_50m.tif Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The USGS shall not be held liable for improper or incorrect use of the data described or contained herein. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. GeoTIFF ZIP 1.41 https://coastal.er.usgs.gov/data-release/doi-F7028QFV/data/2008to2009minus1916to1920_MS_NAD83NAVD88g12B_50m.zip None 20201013 Noreen A. Buster U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center Geologist mailing and physical

600 4th Street South

St. Petersburg FL 33701 USA (727) 502-8000 nbuster@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 none unclassified none