2001 Vectorized Shoreline for Breton Island, Louisiana (Geographic, NAD83)

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Frequently anticipated questions:

What does this data set describe?

2001 Vectorized Shoreline for Breton Island, Louisiana (Geographic, NAD83)
A first-surface elevation map was produced cooperatively from remotely sensed, geographically referenced elevation measurements collected by the U.S. Geological Survey (USGS) and National Aeronautics and Space Administration (NASA) on September 07-09, 2001. Elevation measurements were collected over the area using the NASA Airborne Topographic Mapper (ATM), a scanning lidar system that measures high-resolution topography of the land surface. The ATM system is deployed on a Twin Otter or P-3 Orion aircraft and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. This dataset contains vectorized shorelines created from data acquired from Breton Island, Louisiana. Shorelines were vectorized in ArcMap 10.2.2 so they could be used for area and shoreline change analysis, using the Digital Shoreline Analysis System (DSAS) Version 4.0.
  1. How might this data set be cited?
    Terrano, Joseph F., Smith, Kathryn E., and Flocks, James G., 20160125, 2001 Vectorized Shoreline for Breton Island, Louisiana (Geographic, NAD83): U.S. Geological Survey Data Release doi:10.5066/F7XS5SGM, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -89.181277
    East_Bounding_Coordinate: -89.168168
    North_Bounding_Coordinate: 29.497321
    South_Bounding_Coordinate: 29.478429
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 07-Sep-2001
    Ending_Date: 09-Sep-2001
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data (Polyline)
  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 (4)
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      UTM_Zone_Number: 16
      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 meter
      The horizontal datum used is D North American 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?
    Shapefile (Source: USGS)
    Feature geometry (Source: ESRI) Coordinates defining the features
    Automatically assigned values used to identify features (Source: ESRI)
    Range of values
    Length of feature in internal units. (Source: Esri)
    Range of values
    A value representing the error associated with the imagery type that is used in the Digital Shoreline Analysis System (DSAS) statistical computations. (Source: USGS)
    1.9Automatically generated values used to identify features.
    Date imagery was collected for Breton Island using the mm/dd/yyyy format. Imagery dates for data not representing Breton Island were excluded. (Source: USGS) Date using the mm/dd/yyyy format
    Shoreline classification used to separate foreshore and backshore shorelines. (Source: USGS) Shorelines classified as "Fore" for foreshore and "Back" for backshore shorelines.
    4-digit year in which the imagery was collected. (Source: USGS) Single year in the YYYY format

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Joseph F. Terrano
    • Kathryn E. Smith
    • James G. Flocks
  2. Who also contributed to the data set?
    Funds for this report are part of project funds for the Louisiana Outer Coast Early Restoration Project, obtained by the natural resource trustees for the Deepwater Horizon Oil Spill, pursuant to the Framework for Early Restoration Addressing Injuries Resulting from the Deepwater Horizon Oil Spill executed April 20, 2011. USFWS is the project lead for the North Breton Island Barrier Island Restoration project. 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
    Attn: Joseph F. Terrano
    Researcher 1
    600 4th Street South
    St. Petersburg, Florida

    (727) 502-8047 (voice)
    (727) 502-8001 (FAX)
    Monday through Friday, 9:00 a.m. to 5:00 p.m., Eastern Standard Time

Why was the data set created?

Shoreline data are considered a crucial element in performing change analysis for erosion and accretion studies and for tracking shoreline movement over time; lidar data was downloaded and used to document the short and long-term changes of several barrier island systems in Louisiana. Vectorized shorelines, created from the Lidar data, provide an accurate and measurable change in shape, area, and shoreline movement over short and long-term periods.

How was the data set created?

  1. From what previous works were the data drawn?
    USGS DS 465 (source 1 of 1)
    U.S. Geological Survey, 2009, ATM Coastal Topography--Louisiana, 2001: UTM Zone 16 (Part 2 of 2).

    Online Links:

    Type_of_Source_Media: Online
    Source_Scale_Denominator: 1500
    Lidar-derived elevations were used to identify the mean high water (MHW) location for shoreline delineation.
  2. How were the data generated, processed, and modified?
    Date: 01-Jun-2015 (process 1 of 3)
    The data were collected using a Twin Otter aircraft. Attached to the aircraft was the NASA Airborne Topographic Mapper (ATM) laser scanner, which collected the data using a green raster scanning laser. The raw and processed data are stored on hard drives and archived at the U.S. Geological Survey's office in St. Petersburg, FL, and the NASA office at Wallops Flight Facility in Virginia. The navigational data were processed at Wallops Flight Facility. The navigational and raw data were downloaded into the Advanced Lidar Processing System (ALPS), where it was converted from units of time to x,y,z points for elevation. The derived surface data can then be converted into raster data in the form of a digital elevation model (GeoTIFFs), which consists of cells containing elevation data. The input parameters for the random consensus filter (RCF) were as follows: grid cell size (buffer) = 8 meters by 8 meters; vertical tolerance (vertical width) = 20 centimeters. The variables measured by ATM are distance between aircraft and GPS satellites (meters), attitude information (roll, pitch, heading in degrees), scan angle (degrees), second of the epoch (seconds), and 1-nanosecond time-resolved return intensity waveform (digital counts). Z value is referenced to orthometric elevations derived from National Geodetic Survey Geoid Model, GEOID03. Raster data are projected to Universal Transverse Mercator (UTM), Zone 16, North American Datum (NAD) 1983, meters (m) coordinates. To vectorize the shorelines, the lidar digital elevation model (DEM) data were added to ArcMap 10.2.2. The symbology of the map was changed to classify the image into two elevation classes at 0.23 meters, delineating the location of the average mean high water (MHW) shoreline for the Breton Island area. The MHW elevation was determined by tide gauge measurements reported in Morton and others (2004). The two-class raster was then examined against aerial imagery and it was determined that this elevation provided a good approximation of the MHW shoreline via visual inspection of the wet/dry sand line. After the value of 0.23 was chosen, the ArcMap tool "Contour List" was used to create a shoreline. To remove any sharp edges from the shoreline the ArcMap tool "Smooth Line" was used. Using the Edit tool, any extra lines, overlapping lines, and remaining sharp angle lines were removed. If needed, some areas were hand digitized to ensure they matched the Lidar data, which was classified to 0.23. After the shoreline was edited, it was checked for any remaining errors using ArcMap 10.2.2 "Create Topology" tool. Five rules were added to ensure that the shorelines were matching up correctly. The five rules are that the shorelines must not have dangles, must not intersect (line), must not overlap (line), must not self-intersect (line), and must not self-overlap (line). Next, using the validate topology tool, error markers were added to the shoreline shapefile to show if there were any shorelines that needed to be fixed. These errors were fixed accordingly, to ensure that the shoreline was continuous and free of errors. Shorelines were then split at the northern most point and the southern most point to create a foreshore and backshore shoreline. In addition, the following fields were added to the shoreline’s attribute table and calculated as necessary: "UNCERTAINT" (double), "DATE_" (Text/10), "Shoreline_" (Text/20), and "Year" (Text/10). Person who carried out this activity:
    U.S. Geological Survey
    Attn: Joseph Terrano
    600 4th Street South
    St. Petersburg, Florida

    (727) 502-8047 (voice)
    (727) 502-8001 (FAX)
    Monday through Friday, 9:00 a.m. to 5:00 p.m., Eastern Standard Time
    Date: 13-Mar-2017 (process 2 of 3)
    Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    Date: 13-Oct-2020 (process 3 of 3)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
  3. What similar or related data should the user be aware of?
    Martinez, L., O’Brien, S., Bethel, M., Penland, S., and Kulp, M., 2009, Louisiana Barrier Island Comprehensive Monitoring Program (BICM)   Volume 2: Shoreline Changes and Barrier Island Land Loss 1800’s‐2005.

    Online Links:

    Yates, Xan, Nayegandhi, Amar, Brock, J.C., Sallenger, A.H., Klipp, E.S., and Wright, C.W., 2009, ATM Coastal Topography--Louisiana, 2001: UTM Zone 16 (Part 2 of 2).

    Online Links:

    Morton, R.A., Miller, T.L., and Moore, L.J., 2008, National Assessment of Shoreline Change: Part 1, Historical Shoreline Changes and Associated Coastal Land Loss Along the U.S. Gulf of Mexico.

    Online Links:

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

  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Shorelines that did not represent the main shoreline of Breton Island, such as the Chandeleur Islands or the Mississippi River Delta were removed. To ensure accuracy, edited shorelines were compared to those shown on the Breton Island, LA T-sheets created from 1869-2014, as a method for maintaining consistency between which islands were removed from each of the shoreline datasets.
  5. How consistent are the relationships among the observations, including topology?
    Vectorized shorelines were checked to ensure they were one continuous line. Dangles (or extra line segments) were removed, as necessary. The shorelines were split into foreshore and backshore, based on a visual assessment.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None
The U.S. Geological Survey requests to be acknowledged as originator of the data in future products or derivative research.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    Attn: James Flocks
    600 4th Street South
    St. Petersburg, Florida

    (727) 502-8012 (voice)
    (727) 502-8001 (FAX)
    Monday through Friday, 9:00 a.m. to 5:00 p.m., Eastern Standard Time
    Contact_Instructions: All of this report is available online.
  2. What's the catalog number I need to order this data set? Breton_Island_2001_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?

Who wrote the metadata?

Last modified: 13-Oct-2020
Metadata author:
U.S. Geological Survey
Attn: Joseph Terrano
600 4th Street South
St. Petersburg, Florida

(727) 502-8047 (voice)
(727) 502-8001 (FAX)
Monday through Friday, 9:00 a.m. to 5:00 p.m., Eastern Standard Time
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/Breton_Island_2001_Shoreline_Metadata.faq.html>
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