GrandBay_2010_Shoreline.shp - Grand Bay, Mississippi/Alabama, Shoreline Data Derived from 2010 Aerial Imagery

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Frequently anticipated questions:


What does this data set describe?

Title:
GrandBay_2010_Shoreline.shp - Grand Bay, Mississippi/Alabama, Shoreline Data Derived from 2010 Aerial Imagery
Abstract:
GrandBay_2010_Shoreline.zip features a digitized historical shoreline for the Grand Bay, Mississippi (MS) coastline (Pascagoula, MS to Point aux Pins, Alabama [AL]) derived from 2010 aerial imagery. Imagery of the Mississippi and Alabama coastlines was acquired from the National Agriculture Imagery Program (NAIP) and the city of Mobile, AL. Using ArcMap 10.3.1, the imagery was used to delineate and digitize the historical shoreline as either the Wet Dry Line (WDL) along sandy beaches or the vegetation edge along the marsh coastline at a scale of 1:1000. This shoreline was digitized for use in long-term shoreline and wetland analyses and physical change assessment.
  1. How might this data set be cited?
    Nelson, Paul R., and Smith, Christopher G., 20180525, GrandBay_2010_Shoreline.shp - Grand Bay, Mississippi/Alabama, Shoreline Data Derived from 2010 Aerial Imagery: U.S. Geological Survey Data Release doi:10.5066/F7VT1R8Q, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -88.4961
    East_Bounding_Coordinate: -88.3027
    North_Bounding_Coordinate: 30.4263
    South_Bounding_Coordinate: 30.3183
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 30-Mar-2010
    Ending_Date: 24-May-2010
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • String (898)
    2. What coordinate system is used to represent geographic features?
      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 coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.6096
      Ordinates (y-coordinates) are specified to the nearest 0.6096
      Planar coordinates are specified in meters
      The horizontal datum used is North_American_Datum_1983.
      The ellipsoid used is GRS_1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.
  7. How does the data set describe geographic features?
    Grandbay_2010_Shoreline
    Esri polyline shapefile of shoreline features (WDL or vegetated edge) delineated from 2010 aerial imagery. A table containing attribute information associated with this dataset is included in GrandBay_2010_Shoreline.zip and described below. (Source: USGS)
    FID
    Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: Esri) Coordinates defining the features.
    DigScale
    Reference scale used in ArcGIS 10.3.1 to identify and digitize the shoreline from aerial images. (Source: USGS)
    ValueDefinition
    1:1000Ratio of image viewed in ArcGIS 10.3.1 relative to real world conditions.
    VecLength
    Linear distance, in meters, of the digital feature (line) representing the shoreline. (Source: USGS)
    Range of values
    Minimum:0.0240351824446
    Maximum:108319.648526
    dImageDate
    Date of image collection provided to USGS staff by the data source (see Source_Information of the Lineage section for additional details), stored in date format (M/DD/YYYY). (Source: USGS)
    ValueDefinition
    3/30/2010Date of image collection provided by the City of Mobile (Alabama) GIS Department.
    5/24/2010Date of image collection provided with the USDA NAIP image mosaic.
    sImageDate
    Date of image collection provided by NAIP stored in string format ('MM/DD/YYYY hh:mm:ss AM/PM'). (Source: USGS)
    ValueDefinition
    03/30/2010 12:00:00 AMDate of image collection provided by City of Mobile (Alabama) GIS Department.
    05/24/2010 12:00:00 AMDate of image collection provided for USDA NAIP image mosaic.
    ShoreType
    Character string used to denote the shoreline type that was present as the shoreline was digitized. (Source: USGS)
    ValueDefinition
    MarshTerm used to denote when the shoreline was manually identified as marsh or vegetated edge/boundary.
    SandTerm used to denote when the shoreline was identified as sandy shoreline.
    DigFeat
    Term used denoting digitized-shoreline feature given the reference scale. (Source: USGS)
    ValueDefinition
    VegTerm used denoting that a vegetated-edge was digitized as the shoreline.
    WDLTerm used denoting that the Wet Dry Line (WDL) on a sloping surface was digitized as the shoreline. There is no available information about beach slope.
    ImageRes
    Horizontal image resolution, in meters, provided by the NAIP. (Source: USGS)
    Range of values
    Minimum:0.5
    Maximum:1
    ImagUnc
    Horizontal uncertainty, in meters, of orthorectified image provided by the NAIP or City of Mobile. (Source: USGS)
    Range of values
    Minimum:1.2192
    Maximum:6
    ShoreUnc
    Horizontal uncertainty, in meters, of digitized shoreline feature based on image resolution and horizontal uncertainty. It was computed as the square root of the sum of squares of the image resolution, image uncertainty, and the maximum digitization error of 1 meter reported by other studies (Anders & Byrnes, 1991; Crowell and Leatherman, 1991; Morton and others, 2004). The no data value, -999, reflects areas where the WDL was digitized and uncertainty in shoreline position cannot be computed in this manner, confidently, due to the lack of beach slope information. (Source: USGS)
    Range of values
    Minimum:-999
    Maximum:6.08276253

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Paul R. Nelson
    • Christopher G. Smith
  2. Who also contributed to the data set?
    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.
  3. To whom should users address questions about the data?
    U.S. Geological Survey Coastal and Marine Science Center
    Attn: Christopher G. Smith
    600 4th Street South
    St. Petersburg, FL

    727-502-8035 (voice)
    727-502-8182 (FAX)
    cgsmith@usgs.gov

Why was the data set created?

Shoreline data are considered a crucial element in performing change analyses for erosion and accretion studies for tracking shoreline movement over time. Aerial imagery was used to digitize a set of polylines (feature) that reflect the Grand Bay shoreline position for the year 2010. The digitized feature captures the shape of the shoreline and provides an accurate and measurable position that can be used for various assessments. When this shoreline is combined with other historical shorelines from the area digitized in a similar manner, quantitative rates of change of shoreline position can be determined. Therefore these data can aid in developing an understanding of the temporal and spatial evolution of the coastline.

How was the data set created?

  1. From what previous works were the data drawn?
    AL_Orthophoto_2010 (source 1 of 2)
    Scott Kearney - City of Mobile, AL, Unpublished material, Orthophotography.

    Other_Citation_Details:
    2010 planimetric data can be ordered, in DVD format, from the City of Mobile Geographic Information Systems Department. Contact details are available at, http://maps.cityofmobile.org/GIS/gisdata.aspx.
    Type_of_Source_Media: Digital and/or Hardcopy Resources
    Source_Scale_Denominator: 12000
    Source_Contribution: Imagery was used to delineate and digitize shoreline positions.
    MS_Orthophoto_2010 (source 2 of 2)
    USDA/FSA - Aerial Photography Field Office, 2010, USDA-FSA-APFO NAIP MrSID Mosaic: USDA-FSA-APFO, Salt Lake City, UT.

    Type_of_Source_Media: Digital and/or Hardcopy Resources
    Source_Scale_Denominator: 12000
    Source_Contribution: Imagery was used to delineate and digitize shoreline positions.
  2. How were the data generated, processed, and modified?
    Date: 19-Nov-2017 (process 1 of 2)
    Imagery was acquired from multiple agencies as direct download or as hard copy. All data were provided orthorectified to provide the highest accuracy. Imagery was brought in ArcGIS 10.3.1 for overlay and further mapping. Person who carried out this activity:
    Christopher G. Smith
    U.S. Geological Survey
    600 4th Street South
    St. Petersburg, Florida
    US

    727-502-8035 (voice)
    727-502-8182 (FAX)
    cgsmith@usgs.gov
    Data sources used in this process:
    • AL_Orthophoto_2010
    • MS_Orthophoto_2010
    Data sources produced in this process:
    • GrandBay_2010_Shoreline.shp
    Date: 19-Nov-2017 (process 2 of 2)
    Using ArcMap 10.3.1, aerial images were visually assessed for shoreline features at a reference scale of 1:1000. Shoreline features used, that is the shoreline mapped, were the Wet Dry Line (WDL) along sandy beaches or marsh-wetland edge along vegetated shorelines. The digitization was implemented using the ArcMap 10.3.1 Editor Toolbar part of the Esri ArcGIS software suite. Typology errors (a form of quality control for vector data) were assessed after the full shoreline was digitized using a cluster tolerance of 0.001 and typological rules to identify OVERLAPS, INTERSECTS, DANGLES, SELF-INTERSECTS, and SELF-OVERLAPS. All such features (except the start and end points at the most western and eastern extents of the area) were removed or corrected to ensure a single continuous feature. Person who carried out this activity:
    Christopher G. Smith
    U.S. Geological Survey
    600 4th Street South
    St. Petersburg, Florida
    US

    727-502-8035 (voice)
    727-502-8182 (FAX)
    cgsmith@usgs.gov
    Data sources used in this process:
    • AL_Orthophoto_2010
    • MS_Orthophoto_2010
    Data sources produced in this process:
    • GrandBay_2010_Shoreline.shp
  3. What similar or related data should the user be aware of?
    Anders, F.J., and Byrnes, M.R., 1991, Accuracy of shoreline change rates as determined from maps and aerial photographs: Shore and Beach 59(1):17-26.

    Crowell, M., Leatherman, S.P., and Buckley, M.K., 1991, Historical shoreline change: error analysis and mapping accuracy.: Journal of Coastal Research 7(3):839-852.

    Morton, R.A., Miller, T.L., and Moore, L.J., 2004, National assessment of shoreline change: Part 1: Historical shoreline changes and associated coastal land loss along the U.S. Gulf of Mexico: U.S. Geological Survey Open-File Report 2004-1043, U.S. Geological Survey, Coastal and Marine Geology Program, St. Petersburg Coastal & Marine Science Center, St. Petersburg, FL.

    Online Links:


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    No formal attribute accuracy tests were conducted.
  2. How accurate are the geographic locations?
    A formal accuracy assessment of the horizontal positional information in the dataset has not been conducted.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    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.
  5. How consistent are the relationships among the observations, including topology?
    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 subsequent use within shoreline change analysis programs.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
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.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey Coastal and Marine Science Center
    Attn: Christopher G. Smith
    600 4th Street South
    St. Petersburg, FL

    727-502-8035 (voice)
    727-502-8182 (FAX)
    cgsmith@usgs.gov
  2. What's the catalog number I need to order this data set? GrandBay_2010_Shoreline.shp
  3. What legal disclaimers am I supposed to read?
    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.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: The download file (.zip format) included in this data release contains a shapefile of an aerial-imagery derived shoreline from 2010 for Grand Bay, Mississippi and Alabama. in format SHP (Esri Shapefile)
      Network links: https://coastal.er.usgs.gov/data-release/doi-F7VT1R8Q/data/GrandBay_2010_Shoreline.zip
    • Cost to order the data: None. No fees are applicable for obtaining the dataset.


Who wrote the metadata?

Dates:
Last modified: 24-May-2018
Metadata author:
U.S. Geological Survey Coastal and Marine Science Center
Attn: Christopher G. Smith
600 4th Street South
St. Petersburg, FL

727-502-8035 (voice)
727-502-8182 (FAX)
cgsmith@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/GrandBay_2010_Shoreline_metadata.faq.html>
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