Identification_Information: Citation: Citation_Information: Originator: Paul R. Nelson Originator: Rachel E. Henderson Originator: Christopher G. Smith Originator: Joseph W. Long Publication_Date: 20170623 Title: Aerial_Shorelines_1940_2015.shp - Dauphin Island, Alabama Shoreline Data Derived from Aerial Imagery from 1940 to 2015 Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: U.S. Geological Survey Data Release Issue_Identification: doi:10.5066/F7T43RB5 Publication_Information: Publication_Place: St. Petersburg, FL Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/F7T43RB5 Description: Abstract: Aerial_WDL_Shorelines.zip features digitized historic shorelines for the Dauphin Island coastline from October 1940 to November 2015. This dataset contains 10 Wet Dry Line (WDL) shorelines separated into 58 shoreline segments alongshore Dauphin Island, AL. The individual sections are divided according to location along the island and shoreline type: open-ocean, back-barrier, marsh shoreline. Imagery of Dauphin Island, Alabama was acquired from several sources including the United States Geological Survey (USGS), the National Agriculture Imagery Program (NAIP), the United States Department of Agriculture's Farm Service Agency (USDA, FSA), and the University of Alabama. These images were downloaded directly from the source's website or received as a hard copy via mail. Using ArcMap 10.3.1, the imagery was used to delineate and digitize historical shorelines at the wet-dry line along sandy beaches and the mean high water line where vegetation indicated. These shorelines were digitized for use in long-term shoreline and wetland analyses and physical change assessments. Shorelines for all 10 dates were compiled into a database for use with the Digital Shoreline Analysis System (DSAS; Thieler and others, 2009) to quantify rates of shoreline change over the 1940-2015 time period. The migration of shorelines through time is presented as the linear regression rate (LRR) in the associated back-barrier and open ocean transect files, which are also included in the USGS data release (https://coastal.er.usgs.gov/data-release/provisional/ip086178/). Purpose: Shoreline data are considered a crucial element in performing change analysis for erosion and accretion studies for tracking shoreline movement over time. Aerial imagery was used to digitize the Dauphin Island coastline to document the short- and long-term changes of the selected study area. The digitized shorelines provide an accurate and measurable change in shape, area, and shoreline movement over a short and long period of time. Shorelines derived from these aerial images provide information about the position of the island through time and are used to quantify the rate of change during this time period. These data will aid in developing an understanding of the evolution of the barrier island position, size and shape as well as documenting spatially-variable patterns in erosion and accretion of different sections of the island. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19401027 Ending_Date: 20151112 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: As needed Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -88.344204 East_Bounding_Coordinate: -88.052726 North_Bounding_Coordinate: 30.287151 South_Bounding_Coordinate: 30.192035 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Shoreline Data Theme_Keyword: Shoreline Map Theme_Keyword: Wet Dry Line Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme_Keyword: oceans Theme_Keyword: environment Theme_Keyword: elevation Theme_Keyword: boundaries Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: coastal processes Theme_Keyword: marine geology Theme_Keyword: geomorphology Theme_Keyword: remote sensing Theme_Keyword: unconsolidated deposits Theme_Keyword: aerial photography Theme_Keyword: digitization Place: Place_Keyword_Thesaurus: None Place_Keyword: Dauphin Island Place_Keyword: Gulf of Mexico Place_Keyword: USA Place_Keyword: Alabama Place_Keyword: AL Access_Constraints: None Use_Constraints: The U.S. Geological Survey requests to be acknowledged as originator of the data in future products or derivative research. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Coastal and Marine Science Center Contact_Person: Paul R. Nelson Contact_Address: Address_Type: Mailing Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Contact_Voice_Telephone: 727-502-8127 Contact_Facsimile_Telephone: 727-502-8182 Contact_Electronic_Mail_Address: prnelson@usgs.gov Data_Set_Credit: Acknowledgment of the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, 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. Native_Data_Set_Environment: Environment as of Metadata Creation: Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.3.1 (Build 4959) Service Pack N/A (Build N/A) Cross_Reference: Citation_Information: Originator: M. J. Pajak Originator: S. Leatherman Publication_Date: 2002 Title: The High Water Line as Shoreline Indicator Series_Information: Series_Name: Journal Issue_Identification: Vol. 18, No. 2 Publication_Information: Publication_Place: Coastal Education & Research Foundation, Inc. Publisher: Journal of Coastal Research Online_Linkage: http://www.jstor.org/stable/4299078 Cross_Reference: Citation_Information: Originator: E.R. Thieler Originator: E.A. Himmelstoss Originator: J.L. Zichichi Originator: A. Ergul Publication_Date: 2009 Title: Digital Shoreline Analysis System (DSAS) version 4.0 - An ArcGIS extension for calculating shoreline change Series_Information: Series_Name: Open-File Report Issue_Identification: 2008-1278 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center Other_Citation_Details: Although the citation is for v. 4.0, the version of software at time of use was 4.3 Online_Linkage: https://pubs.er.usgs.gov/publication/ofr20081278 Cross_Reference: Citation_Information: Originator: C.J. Hapke Originator: D. Reid Originator: B.M. Richmond Originator: P. Ruggiero Originator: J. List Publication_Date: 2006 Title: National Assessment of Shoreline Change: Part 3: Historical Shoreline Changes and Associated Coastal Land Loss along the Sandy Shorelines of the California Coast Series_Information: Series_Name: Open-File Report Issue_Identification: 2006-1219 Publication_Information: Publication_Place: Woods Hole Coastal & Marine Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: https://pubs.usgs.gov/of/2006/1219/ Cross_Reference: Citation_Information: Originator: Cheryl J. Hapke Originator: Emily A. Himmelstoss Originator: Meredith G. Kratzmann Originator: Jeffrey List Originator: E. Robert Thieler Publication_Date: 20110223 Title: National Assessment of Shoreline Change: Historical Shoreline Change along the New England and Mid-Atlantic Coasts Series_Information: Series_Name: Open-File Report Issue_Identification: 2010-1118 Publication_Information: Publication_Place: Woods Hole Coastal and Marine Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: https://pubs.usgs.gov/of/2010/1118/ Cross_Reference: Citation_Information: Originator: R. A. Morton Originator: T.L. Miller Publication_Date: 2005 Title: National Assessment of Shoreline Change: Part 2: Historical Shoreline Changes and Associated Coastal Land Loss along the U.S. Southeast Atlantic Coast Series_Information: Series_Name: Open-File Report Issue_Identification: 2005-1401 Publication_Information: Publication_Place: Woods Hole Coastal & Marine Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Other_Citation_Details: none Online_Linkage: http://pubs.usgs.gov/of/2005/1401/ Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The data provided here are a compilation of shorelines from aerial imagery from 1940 to 2015. The attributes are based on the requirements of the Digital Shoreline Analysis System (DSAS) software and have gone through a series of quality assurance procedures. Logical_Consistency_Report: Digitized shorelines were checked to ensure they were one continuous line and were checked for dangles (or extra line segments), which were removed, when necessary. Larger estuarine channels were digitized, as needed, to ensure a complete shoreline for later use within shoreline change programs. Completeness_Report: Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: In order to determine the uncertainties associated with individual shorelines, a methodology following Morton and Miller (2005) and Hapke and others, (2006) was used to estimate a positional uncertainty value for each shoreline. Total shoreline positional uncertainty is a function of the errors inherent in the source data (georeferencing Root Mean Square [RMS]) the interpretation of the shoreline feature (WDL positional variability) and those errors generated in the digitization of the vector shoreline (interpolation uncertainty/cell size). Three terms were identified to describe the shoreline positional uncertainty of the WDL shoreline. The first is the total image Root Sum Squared (RSS) of the georeferenced aerial imagery. This measure takes into account the accuracy of the georeferenced image, as well as the uncertainty of the base to wich the imagery was georeferenced to. The second term is based on the natural variability of the shoreline proxy. The positional variability of an interpolated WDL shoreline is influenced primarily by tides, winds, waves and beach slope. Similarly, other water level based proxies (HWL - high water line, LHTS- last high tide swash) have positional variability, which is weather and tide dependent. Drawing on methods presented in Pajak and Leathermann (2002), a conservative estimate of WDL variability (given tide range and average beach slope) of 4.5 m is calculated for Dauphin Island. The third and final term is based on the cell size of the georeferenced image, which relates to the scale of the image and accounts for limitations of shoreline interpretation from the raster data. These terms were summed in quadrature and the resulting shoreline positional uncertainty was applied to each shoreline date in the "UNCERT" field of the attribute table. This value is used to determine the uncertainty of shoreline change rates when used with the Digital Shoreline Analysis System (DSAS; Thieler and others, 2009). Quantitative_Horizontal_Positional_Accuracy_Assessment: Horizontal_Positional_Accuracy_Value: 9.7 Horizontal_Positional_Accuracy_Explanation: The horizontal positional accuracy value is presented as an average of the 10 aerial shoreline uncertainty values. Each shoreline was assigned a unique uncertainty based on: 1) RSS of the georeferenced aerial imagery 2) estimate of WDL variability 3) cell size limitation. The following are the estimated uncertainties for each date. Values are in meters. 19401027 (10.5) 19520429 (13.0) 19601102 (9.4) 19741204 (9.2) 19850601 (10.9) 19890918 (11.8) 19920201 (8.4) 19972011 (8.4) 20060623 (7.6) 20151112 (7.5) Average = 9.7 m Lineage: Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey (USGS) Publication_Date: 19740429 Title: Aerial Single Frame Photos - Dauphin Island 1940 Geospatial_Data_Presentation_Form: Photos Publication_Information: Publication_Place: Sioux Falls, South Dakota Publisher: U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center Other_Citation_Details: The Aerial Photography Single Frame Records collection is a large and diverse group of imagery acquired by Federal organizations from 1937 to the present. Over 6.4 million frames of photographic images are available for download as medium and high resolution digital products. The high resolution data provide access to photogrammetric quality scans of aerial photographs with sufficient resolution to reveal landscape detail and to facilitate the interpretability of landscape features. Coverage is predominantly over the United States and includes portions of Central America and Puerto Rico. Individual photographs vary in scale, size, film type, quality, and coverage. Online_Linkage: https://lta.cr.usgs.gov/Single_Frame_Records Source_Scale_Denominator: 48000 Type_of_Source_Media: Digital and/or Hardcopy Resources. Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 19401027 Source_Currentness_Reference: Ground Condition Source_Citation_Abbreviation: Dauphin_1940 Source_Contribution: Imagery provided by EROS via direct download. Imagery was georectified and then used to delineate and digitize shoreline positions. Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey (USGS) Publication_Date: 19750707 Title: Aerial Single Frame Photos - Dauphin Island 1952 Geospatial_Data_Presentation_Form: Photos Publication_Information: Publication_Place: Sioux Falls, South Dakota Publisher: U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center Other_Citation_Details: The Aerial Photography Single Frame Records collection is a large and diverse group of imagery acquired by Federal organizations from 1937 to the present. Over 6.4 million frames of photographic images are available for download as medium and high resolution digital products. The high resolution data provide access to photogrammetric quality scans of aerial photographs with sufficient resolution to reveal landscape detail and to facilitate the interpretability of landscape features. Coverage is predominantly over the United States and includes portions of Central America and Puerto Rico. Individual photographs vary in scale, size, film type, quality, and coverage. Online_Linkage: https://lta.cr.usgs.gov/Single_Frame_Records Source_Scale_Denominator: 69000 Type_of_Source_Media: Digital and/or Hardcopy Resources Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 19520430 Source_Currentness_Reference: Ground Condition Source_Citation_Abbreviation: Dauphin_1952 Source_Contribution: Imagery provided by EROS via direct download. Imagery was georectified and then used to delineate and digitize shoreline positions. Source_Information: Source_Citation: Citation_Information: Originator: United States Department of Agriculture - Farm Service Agency Publication_Date: Unknown Title: Aerial Imagery Mobile County, Alabama, 1960 Publication_Information: Publication_Place: Salt Lake City, Utah Publisher: United States Department of Agriculture - Farm Service Agency Other_Citation_Details: The Aerial Photography Field Office (APFO) has a vast amount of imagery of the United States and its territories from 1955 to the present. Online_Linkage: https://www.fsa.usda.gov/programs-and-services/aerial-photography/index Source_Scale_Denominator: 20000 Type_of_Source_Media: Digital and/or Hardcopy Resources Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 19601102 Source_Currentness_Reference: Ground Condition Source_Citation_Abbreviation: Dauphin_1960 Source_Contribution: Imagery provided by USDA-FSA as high-resolution scans(.tif) on hard disk via post. Imagery was georectified and then used to delineate and digitize shoreline positions. Source_Information: Source_Citation: Citation_Information: Originator: Geological Survey of Alabama - Acquired from University of Alabama's Cartographic Research Laboratory. Publication_Date: Unknown Title: Aerial Photography Mobile County, Alabama, 1974 Publication_Information: Publication_Place: Tuscaloosa, Alabama Publisher: Cartographic Research Laboratory Other_Citation_Details: Alabama Maps is an ongoing project of the Cartographic Research Laboratory, which operates under the auspices of the College of Arts and Sciences at the University of Alabama. The Cartographic Research Laboratory , established in 1982, is a self-supporting, nonprofit facility, receiving funding through the sale of our publications and projects from clientele. The Aerial Photography Index contains a digitized selection of historic aerial photography found at the Geological Survey of Alabama and the University of Alabama Map Library. The photos found in this index are but a small part of the total collection of nearly 150,000 photographs housed in these facilities. Online_Linkage: http://alabamamaps.ua.edu Source_Scale_Denominator: 40000 Type_of_Source_Media: Digital and/or Hardcopy Resources Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 19741204 Source_Currentness_Reference: Ground Condition Source_Citation_Abbreviation: Dauphin_1974 Source_Contribution: Imagery provided by the Cartographic Research Laboratory as high-resolution scans (.tif) via direct download. Imagery was georectified and then used to delineate and digitize shoreline positions. Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey (USGS) Publication_Date: 19980804 Title: National High Altitude Photography, Mobile County, Alabama, 1985 Publication_Information: Publication_Place: Sioux Falls, South Dakota Publisher: U.S. Geological Survey (USGS) ) Earth Resources Observation and Science (EROS) Center Other_Citation_Details: The National High Altitude Photography (NHAP) program, which was operated from 1980-1989, was coordinated by the U.S. Geological Survey as an interagency project to eliminate duplicate photography in various government programs. The aim of the program was to cover the 48 conterminous states over a 5-year span. In the NHAP program, black-and-white and color-infrared aerial photographs were obtained on 9-inch film from an altitude of 40,000 feet above mean terrain elevation and are centered over USGS 7.5-minute quadrangles. The color-infrared photographs are at a scale of 1:58,000 (1 inch equals about .9 miles), and the black-and-white photographs are at a scale of 1:80,000 (1 inch equals about 1.26 miles). All NHAP flights were flown in a North to South direction. These photographs are offered as digital images. Online_Linkage: https://lta.cr.usgs.gov/NHAP Source_Scale_Denominator: 58000 Type_of_Source_Media: Digital and/or Hardcopy Resources Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 19850325 Source_Currentness_Reference: Ground Condition Source_Citation_Abbreviation: Dauphin_1985 Source_Contribution: Imagery provided by EROS via direct download. Imagery was georectified and then used to delineate and digitize shoreline positions. Source_Information: Source_Citation: Citation_Information: Publication_Date: 19900125 Originator: U.S. Geological Survey (USGS) Title: Aerial Single Frame Photos - Dauphin Island 1989 Geospatial_Data_Presentation_Form: Photo Publication_Information: Publication_Place: Sioux Falls, South Dakota Publisher: U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center Other_Citation_Details: The Aerial Photography Single Frame Records collection is a large and diverse group of imagery acquired by Federal organizations from 1937 to the present. Over 6.4 million frames of photographic images are available for download as medium and high resolution digital products. The high resolution data provide access to photogrammetric quality scans of aerial photographs with sufficient resolution to reveal landscape detail and to facilitate the interpretability of landscape features. Coverage is predominantly over the United States and includes portions of Central America and Puerto Rico. Individual photographs vary in scale, size, film type, quality, and coverage. Online_Linkage: https://lta.cr.usgs.gov/Single_Frame_Records Source_Scale_Denominator: 65000 Type_of_Source_Media: Digital and/or Hardcopy Resources. Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 19890918 Source_Currentness_Reference: Ground Condition Source_Citation_Abbreviation: Dauphin_1989 Source_Contribution: Imagery provided by EROS via direct download. Imagery was georectified and then used to delineate and digitize shoreline positions. Source_Information: Source_Citation: Citation_Information: Publication_Date: 19970514 Originator: U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center Title: Digital Orthophoto Quadrangle, Dauphin Island, Alabama, 1992 Geospatial_Data_Presentation_Form: Remote-Sensing Image Publication_Information: Publication_Place: Menlo Park, CA USA Publisher: U.S. Geological Survey Other_Citation_Details: Orthophotos combine the image characteristics of a photograph with the geometric qualities of a map. The primary digital orthophotoquadrangle (DOQ) is a 1-meter ground resolution, quarter-quadrangle (3.75 minutes of latitude by 3.75 minutes of longitude) image cast on the Universal Transverse Mercator projection (UTM) on the North American Datum of 1983 (NAD83). The geographic extent of the DOQ is equivalent to a quarter-quadrangle plus the overage ranges from a minimum of 50 meters to a maximum of 300 meters beyond the extremes of the primary and secondary corner points. The overage is included to facilitate tonal matching for mosaicking and for the placement of the NAD83 and secondary datum corner ticks. The normal orientation of data is by lines (rows) and samples (columns). Each line contains a series of pixels ordered from west to east with the order of the lines from north to south. The radiometric image brightness values are stored as 256 gray levels, ranging from 0 to 255. The standard, uncompressed gray scale DOQ format contains an ASCII header followed by a series of 8-bit image data lines. The keyword-based, ASCII header may vary in the number of data entries. The header is affixed to the beginning of the image and is composed of strings of 80 characters with an asterisk (*) as character 79 and an invisible newline character as character 80. Each keyword string contains information for either identification, display, or registration of the image. Additional strings of blanks are added to the header so that the length of a header line equals the number of bytes in a line of image data. The header line will be equal in length to the length of an image line. If the sum of the byte count of the header is less than the sample count of one DOQ image line, then the remainder of the header is padded with the requisite number of 80-character blank entries, each terminated with an asterisk and newline character. Online_Linkage: https://lta.cr.usgs.gov/DOQs Source_Scale_Denominator: 40000 Type_of_Source_Media: Digital and/or Hardcopy Resources Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 19920201 Source_Currentness_Reference: Ground Condition Source_Citation_Abbreviation: Dauphin_1992 Source_Contribution: Imagery provided by EROS via direct download. Imagery was used to delineate and digitize shoreline positions. Source_Information: Source_Citation: Citation_Information: Publication_Date: 19970211 Originator: U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center Title: The National Aerial Photography Program Imagery, Mobile County, Alabama, 1997 Geospatial_Data_Presentation_Form: Photograph and/or High Resolution Scanned Image Publication_Information: Publication_Place: Sioux Falls, South Dakota Publisher: U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center Other_Citation_Details: The National Aerial Photography Program (NAPP) was coordinated by the USGS as an interagency project to acquire cloud-free aerial photographs at an altitude of 20,000 feet above mean terrain elevation. The photographs were taken with a 6-inch focal length lens and are at a scale of 1:40,000. Coverage over the conterminous United States includes both black-and-white (BW) and color infrared (CIR) aerial photographs. Film type and extent of coverage were determined by available funds and operational requirements. The NAPP program, which was operational from 1987 to 2007, consists of more than 1.3 million images. Photographs were acquired on 9-inch film and were centered over quarters of USGS 7.5-minute quadrangles.Photographs are available as medium resolution digital images in Tagged Image File Format (TIFF). Medium resolution digital products were created with a digital single-lens reflex camera at a resolution of 63 microns, or 400 dots per inch (dpi). Online_Linkage: https://lta.cr.usgs.gov/NAPP Source_Scale_Denominator: 40000 Type_of_Source_Media: Digital and/or Hardcopy Resources. Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 19970211 Source_Currentness_Reference: Ground Condition Source_Citation_Abbreviation: Dauphin_1997 Source_Contribution: Imagery provided by EROS via direct download. Imagery was georectified and then used to delineate and digitize shoreline positions. Source_Information: Source_Citation: Citation_Information: Originator: USDA-FSA-APFO Publication_Date: 20061206 Title: USDA-FSA-APFO Digital Ortho Mosaic, Mobile County, Alabama, 2006 Geospatial_Data_Presentation_Form: Orthorectified Digital Aerial Photography Publication_Information: Publication_Place: Salt Lake City, Utah Publisher: USDA_FSA_APFO Aerial Photography Field Office Other_Citation_Details: This data set contains imagery from the National Agriculture Imagery Program (NAIP). NAIP acquires digital ortho imagery during the agricultural growing seasons in the continental U.S.. A primary goal of the NAIP program is to enable availability of ortho imagery withone year of acquisition. NAIP provides four main products: 1-meter ground sample distance (GSD) ortho imagery rectified to a horizontal accuracy of within +/- 5meters of reference digital ortho quarter quads (DOQQ's) from the National Digital Ortho Program (NDOP); 2-meter GSD ortho imagery rectified to within +/- 10 meters of reference DOQQs; 1-meter GSD ortho imagery rectified to within +/- 6 meters to true ground; and, 2 meter GSD ortho imagery rectified to within +/- 10 meters to true ground. The tiling format of NAIP imagery is based on a 3.75' x 3.75' quarter quadrangle with a 300-meter buffer on all four sides. NAIP quarter quads are formatted to the UTM coordinate system using NAD83. NAIP imagery may contain as much as 10% cloud cover per tile. Dauphin_2006 was generated by compressing NAIP quarter quadrangle tiles that cover a county. MrSID compression, with mosaic option, was used. Target values for the compression ratio are (15:1) and maximum number of compression levels are used. Online_Linkage: https://gdg.sc.egov.usda.gov Source_Scale_Denominator: 40000 Type_of_Source_Media: Digital and/or Hardcopy Resources. Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20060630 Source_Currentness_Reference: Ground Condition Source_Citation_Abbreviation: Dauphin_2006 Source_Contribution: Imagery provided by USDA Geospatial Data Gateway via direct download. Imagery was used to delineate and digitize shoreline positions. Source_Information: Source_Citation: Citation_Information: Originator: USDA-FSA-APFO Publication_Date: 20151112 Title: USDA-FSA-APFO Digital Ortho Mosaic, Mobile County, Alabama, 2015 Geospatial_Data_Presentation_Form: Orthorectified Digital Aerial Photography Publication_Information: Publication_Place: Salt Lake City, Utah Publisher: USDA_FSA_APFO Aerial Photography Field Office Online_Linkage: https://gdg.sc.egov.usda.gov Source_Scale_Denominator: 12000 Type_of_Source_Media: Digital and/or Hardcopy Resources. Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20151112 Source_Currentness_Reference: Ground Condition Source_Citation_Abbreviation: Dauphin_2015 Source_Contribution: Imagery provided by USDA Geospatial Data Gateway via direct download. Imagery was used to delineate and digitize shoreline positions. Process_Step: Process_Description: Imagery was acquired from multiple agencies as direct download or as hard copy. The images are projected to Universal Transverse Mercator (UTM), Zone 16, North American Datum (NAD) 1983, meters (m) coordinates. If the imagery was not georeferenced when obtained, the corner coordinates and multiple control points were used to georeference the image using the ArcMap 10.3.1 "Georeference" toolbar. Using the ArcMap editor toolbar, shorelines were digitized based on aerial imagery. Shorelines were digitized based on a visual assessment of the WDL along sandy beaches and the approximation of mean high water where vegetation indicated. Shorelines were digitized at a scale of 1:1000. Once digitization was complete, shoreline segments were given attributes “DATE_” (text string 10 characters) and "UNCERT" (double), and "NOTES_". "DATE_" is determined from the aerial imagery collection date in MM/DD/YYYY format, "UNCERT" remains blank until completion of shoreline positional uncertainty (to follow). "NOTES_" contain information about each shoreline segment, according to 1) location along the island (for example, Dauphin Island, Little Dauphin Island, Pelican Island) and shoreline type (open-ocean, back-barrier, marsh shoreline). Once all data was populated with dates, the shoreline years were combined into one shapefile. Source_Used_Citation_Abbreviation: Dauphin_1940 Source_Used_Citation_Abbreviation: Dauphin_1952 Source_Used_Citation_Abbreviation: Dauphin_1960 Source_Used_Citation_Abbreviation: Dauphin_1974 Source_Used_Citation_Abbreviation: Dauphin_1985 Source_Used_Citation_Abbreviation: Dauphin_1989 Source_Used_Citation_Abbreviation: Dauphin_1992 Source_Used_Citation_Abbreviation: Dauphin_1997 Source_Used_Citation_Abbreviation: Dauphin_2006 Source_Used_Citation_Abbreviation: Dauphin_2015 Process_Date: 20160516 Source_Produced_Citation_Abbreviation: Aerial_WDL_Shorelines_1940_2015 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Paul R Nelson Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: Florida Postal_Code: 33701 Country: US Contact_Voice_Telephone: (727)-502-8127 Contact_Electronic_Mail_Address: prnelson@usgs.gov Process_Step: Process_Description: In order to determine the uncertainties associated with individual shorelines, a methodology following Morton and Miller (2005) and Hapke and others, (2006) was used to estimate a positional uncertainty value for each shoreline. Total shoreline positional uncertainty is a function of the errors inherent in the source data (georeferencing RMS) the interpretation of the shoreline feature (WDL positional variability) and those errors generated in the digitization of the vector shoreline (interpolation uncertainty/cell size). Three terms were identified to describe the shoreline positional uncertainty of the WDL shoreline. The first is the total image RSS of the georeferenced aerial imagery. This measure takes into account the accuracy of the georeferenced image, as well as the uncertainty of the base to which the imagery was georeferenced to. The second term is based on the natural variability of the shoreline proxy. The positional variability of an interpolated WDL shoreline is influenced primarily by tides, winds, waves and beach slope. Similarly, other water level based proxies (HWL - high water line, LHTS- last high tide swash) have positional variability which is weather and tide dependent. Drawing on methods presented in Pajak and Leathermann (2002), a conservative estimate of WDL variability (given tide range and average beach slope) of 4.5 m is calculated for Dauphin Island. The third and final term is based on the cell size of the georeferenced image, which relates to the scale of the image and accounts for limitations of shoreline interpretation from the raster data. These terms were summed in quadrature and the resulting shoreline positional uncertainty was applied to each shoreline date in the "UNCERT" field of the attribute table. This value is used to determine the uncertainty of shoreline change rates when used with the Digital Shoreline Analysis System (DSAS; Thieler and others, 2009). Source_Used_Citation_Abbreviation: Aerial_WDL_Shorelines_1940_2015 Process_Date: 20170301 Source_Produced_Citation_Abbreviation: Aerial_Shorelines_1940_2015.shp Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Rachel Henderson Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: Florida Postal_Code: 33701 Country: US Contact_Voice_Telephone: (727)-502-8000 Contact_Electronic_Mail_Address: rehenderson@usgs.gov 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: 58 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 16 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.9996 Longitude_of_Central_Meridian: -87.0 Latitude_of_Projection_Origin: 0.0 False_Easting: 500000.0 False_Northing: 0.0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 0.6096 Ordinate_Resolution: 0.6096 Planar_Distance_Units: Meter Geodetic_Model: Horizontal_Datum_Name: D_North_American_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: Aerial_Shorelines_1940_2015 Entity_Type_Definition: Table containing attribute information associated with the data-set. Entity_Type_Definition_Source: USGS Attribute: Attribute_Label: Shape Attribute_Definition: Feature Geometry Attribute_Definition_Source: Esri Attribute_Domain_Values: Unrepresentable_Domain: Coordinates defining the features. Attribute: Attribute_Label: OBJECTID Attribute_Definition: Internal feature number. Attribute_Definition_Source: Esri Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 1 Range_Domain_Maximum: 58 Attribute: Attribute_Label: DATE_ Attribute_Definition: Date imagery was collected for the Dauphin Island coast using the MM/DD/YYYY format. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 10/27/1940 Range_Domain_Maximum: 11/12/2015 Attribute: Attribute_Label: NOTES Attribute_Definition: Notes about each shoreline segment, according to 1) location along the island (Dauphin Island, Little Dauphin Island, Pelican Island) and shoreline type (open-ocean, back-barrier, marsh shoreline). Attribute_Definition_Source: USGS Attribute_Domain_Values: Unrepresentable_Domain: Additional shoreline information, specific to each line segment. Attribute: Attribute_Label: UNCERT Attribute_Definition: Estimate of shoreline position uncertainty. Actual shoreline position is within the range of this value (plus or minus, meters). Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 7.5 Range_Domain_Maximum: 13 Attribute: Attribute_Label: Shape_Leng Attribute_Definition: System-generated attribute field, which was automatically created by ArcGIS to indicate the feature length. Attribute_Definition_Source: Esri Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 2622.893684 Range_Domain_Maximum: 47110.490534 Attribute_Units_of_Measure: Meters Overview_Description: Entity_and_Attribute_Overview: This datasest contains WDL shoreline data extracted from aerial imagery datasets from 1940 to 2015 with associated attributes for use with the Digital Shoreline Analysis System. Entity_and_Attribute_Detail_Citation: The attributes required for use with DSAS include auto-generated fields - OBJECTID, Shape, Shape_Leng, and user-created fields - DATE_ and UNCERT. The entity and attribute information was generated by the individual and/or agency identified as the originator of the data-set. Please review the rest of the metadata record for additional details and information. Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Coastal and Marine Science Center Contact_Person: Paul R. Nelson Contact_Address: Address_Type: Mailing Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Contact_Voice_Telephone: 727-502-8127 Contact_Facsimile_Telephone: 727-502-8182 Contact_Electronic_Mail_Address: prnelson@usgs.gov Resource_Description: Aerial_Shorelines_1940_2015. Distribution_Liability: This digital publication was prepared by an agency of the United States Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: WinZip Format_Information_Content: This WinZip file contains a shapefile of aerial-imagery derived WDL shorelines from 1940 - 2015 for Dauphin Island, Alabama. File_Decompression_Technique: Use WinZip or pkUnzip Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://coastal.er.usgs.gov/data-release/doi-F7T43RB5/data/Aerial_Shorelines_1940_2015.zip Fees: None. No fees are applicable for obtaining the data-set. Metadata_Reference_Information: Metadata_Date: 20170623 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Coastal and Marine Science Center Contact_Person: Paul R. Nelson Contact_Address: Address_Type: Mailing Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Contact_Voice_Telephone: 727-502-8127 Contact_Facsimile_Telephone: 727-502-8182 Contact_Electronic_Mail_Address: prnelson@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time