U.S. Geological Survey 2015 vector digital data St. Petersburg, Florida. U.S. Geological Survey https://doi.org/10.5066/F7XW4GVG Shorelines Extracted from 1984-2015 Landsat Imagery: Horn Island, Mississippi (Polyline: Individual Dates) is a line shapefile representing shorelines generated from satellite imagery that was collected from 1984 to 2015. The sample frequency of satellite imagery is much higher, and the coverage much greater, than most routine high-resolution topographic surveys. Certain aspects of barrier island morphology, such as island size, shape and position, can be determined from these images and can indicate erosion, land loss, and island breakup. Studying how these characteristics evolve will help develop an understanding of how barrier islands will respond to climate change, sea level rise, and major storms in the future and that will serve to improve management of coastal resources. To document the Horn Island, Miss. shorelines, from March 25, 1984 to May 23, 2015 as observed from Landsat 5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+), and Landsat Operational Land Imager (OLI) satellite imagery. These data will aid in developing an understanding of the change in barrier island size, shape and position, which can indicate erosion, land loss and island breakup. This dataset, horn_lines_individual_dates.zip, and others are included in a USGS Data Release, which can be accessed online at https://doi.org/10.5066/F7XW4GVG. 19840325 20150523 ground condition Complete None planned -88.782547 -88.557259 30.255192 30.216607 USGS Metadata Identifier USGS:12886514-0fd9-4f0e-b715-55c3456c297f None satellite imagery remote sensing Landsat 5 Landsat 7 Landsat 8 Thematic Mapper (TM) Enhanced Thematic Mapper Plus (ETM+) Operational Land Imager (OLI) barrier island shoreline Global Change Master Directory (GCMD) LAND SURFACE > LAND USE/LAND COVER > LAND COVER OCEAN > COASTAL PROCESSES > BARRIER ISLANDS COASTAL PROCESSES > BEACHES DOI/USGS/CMG > COASTAL AND MARINE GEOLOGY, U.S. GEOLOGICAL SURVEY, U.S. DEPARTMENT OF INTERIOR Marine Realms Information Bank (MRIB) Keywords mapping shore shoreline erosion shoreline accretion barrier island migration remote sensing aerial and satellite photography USGS Thesaurus coastal processes erosion shoreline accretion barrier island migration remote sensing None Mississippi Horn Island United States Jackson County Gulf of Mexico Mississippi Sound General 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2013 2014 2015 None. None. However, variability in image quality from one date to another, from one image to another on the same date, and from one part of a single image to another part of the same image, exists due to many factors including variation in sun angle, atmospheric conditions, season, reflectivity of the earth surface, camera angle, camera lens, camera settings, film sensitivity, water turbidity, water depth, tide level, waves, and error in image rectification. No adjustments were made to account for tide level. U.S. Geological Survey Kristy Guy mailing and physical

600 4th St. S.

St. Petersburg FL 33701 USA 727-502-8000 727-502-8181 kguy@usgs.gov Monday through Friday 9:00 AM to 5:00 PM (Eastern Time) Acknowledgment of the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center Coastal and Marine Geology Program (SPCMSC), as a data source would be appreciated in products developed from these data, and such acknowledgment as is standard for citation and legal practices. Sharing of new data layers developed directly from these data would also be appreciated by the U.S. Geological Survey staff. Users should be aware that comparisons with other datasets for the same area from other time periods may be inaccurate due to inconsistencies resulting from changes in photointerpretation, mapping conventions, and digital processes over time. These data are not legal documents and are not to be used as such. Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.2.2.3552. Variations in image quality and in atmospheric and surface conditions may have affected the quality of the shorelines. Tide levels vary from image to image which affects the apparent shoreline. No adjustments were made for varying tide levels. This dataset is considered complete for the information presented, as described in the abstract section. Users are advised to read the rest of the metadata record carefully for additional details. Landsat 7 ETM+ images after May 2003 were not used due to striping caused by the failure of the instrument's scan-line corrector. No shorelines were created for 2012 due to poor Landsat 7 image quality. The horizontal accuracy of the data is unknown. USGS 2011 satellite imagery Sioux Falls, SD USGS Earth Resources Observation and Science (EROS) Center online 19840325 2011019 ground condition Landsat 5 TM This data source was used to identify barrier island shorelines. USGS 2003 satellite imagery Sioux Falls, SD USGS Earth Resources Observation and Science (EROS) Center online 19990722 20030223 ground condition Landsat 7 ETM+ This data source was used to identify barrier island shorelines. USGS 2015 satellite imagery Sioux Falls, SD USGS Earth Resources Observation and Science (EROS) Center online 20130618 20150523 ground condition Landsat 8 OLI This data source was used to identify barrier island shorelines. Landsat 5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+), and Landsat 8 Operational Land Imager (OLI) satellite imagery were acquired in digital format from the U.S. Geological Survey Global Visualization Viewer (http://glovis.usgs.gov/). Images were selected based on cloud-free areas of interest. Landsat 7 ETM+ images after May 2003 were not used due to striping caused by the failure of the instrument's scan-line corrector. The Landsat images were processed using ArcGIS. Images were subset (trimmed) to the area of interest and isolines were generated based on the numerical values of band 7. Band 7, an infrared band (2.08-2.35 µm for TM, 2.09-2.35 µm for ETM+, 2.11-2.29 µm for OLI), clearly distinguishes land from water due to the absorption of these wavelengths by water (Lillesand and Kiefer, 1987) resulting in a low reflectance in contrast to the higher reflectance of land areas, particularly sand. Each isoline was visually compared with its corresponding image and the isoline that best represented the land/water line was selected to represent the shoreline and saved to a shapefile. Wet, marshy shorelines were less reliably delineated using this method and varied more with tide level than the sandy shorelines. When necessary, small hand edits were made to the selected isolines. Predicted tide levels relative to Mean Lower Low Water (MLLW) from the Dauphin Island tide station were obtained from a tide and current prediction program, WXTide32, (www.wxtide32.com) and added as an attribute to horn_ln_19840325_20150523.shp. No adjustments were made to the shorelines for varying tide levels. Landsat 5 TM Landsat 7 ETM+ Landsat 8 OLI 2014 horn_ln_*.shp USGS mailing and physical

600 4th St. S.

St. Petersburg FL 33701 USA 727-502-8000 727-502-8181 Monday through Friday 8:00 AM to 5:00 PM (Eastern Time) If unable to reach the contact by telephone, please leave a voice message. Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. 20170214 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. 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 Vector String 35183 Universal Transverse Mercator 16 0.9996 -87.0 0.0 500000.0 0.0 coordinate pair 0.6096 0.6096 meter Geographic Coordinate System World Geodetic System WGS 1984 World Geodetic System 1984 6378137.0 298.257223563 horn_ln_*.shp Esri polyline features representing Horn Island, Mississippi shorelines from 1984-2015. The SPCMSC created 254 individual date shapefiles. USGS FID Internal feature number. Esri Sequential unique whole numbers that are automatically generated. Shape Feature geometry. Esri Polyline Shape of feature. Esri Date_ Date of satellite image source. USGS Date that the source image was collected in month, day, and year format. YYYYMMDD Date that the source image was collected formatted as an 8-digit number representing the year, month, and day. USGS Date formatted as an 8-digit number representing year, month, and day. WXT32Dau The predicted tide level, in meters relative to MLLW, at the Dauphin Island tide station at the time of image collection. These data were obtained from WXTide32 (www.wxtide32.com), a tide and current prediction program. USGS -0.26 0.58 Landsat The Landsat satellite number. USGS 5 Number of the Landsat satellite. USGS 7 Number of the Landsat satellite. USGS 8 Number of the Landsat satellite. USGS Kristy Guy U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, Fla. GIS/RS Analyst mailing and physical address

600 4th Street South

St. Petersburg FL 33701 USA 727-502-8000 Monday-Friday, 9:00-5:00 Eastern Time Downloadable data - USGS Data Release Although these data were processed successfully on a computer system at the 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 and/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. ArcGIS shapefile http://coastal.er.usgs.gov/data-release/doi-F7XW4GVG/data/horn_lines_individual_dates.zip None if obtained online; otherwise prices vary. Publications are available from USGS Information Services, Box 25286, Federal Center, Denver, CO 80225-0046 (telephone: 1-888-ASK-USGS, e-mail: infoservices@usgs.gov). 20201013 USGS Kristy Guy mailing and physical

600 4th Street South

St. Petersburg FL 33701 USA 727-502-8000 727-502-8181 kguy@usgs.gov Monday through Friday 9:00 AM to 5:00 PM (Eastern Time) FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 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 (USGS)St. Petersburg Coastal and Marine Science Center Coastal and Marine Geology Program as the originator of these data in future products or derivative research. None. Unclassified None.