Breton Island, Louisiana Transects with Shoreline Change Rates (Post-1950s) (Geographic, NAD83)

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Frequently anticipated questions:

What does this data set describe?

Title:
Breton Island, Louisiana Transects with Shoreline Change Rates (Post-1950s) (Geographic, NAD83)
Abstract:
Breton Island, Louisiana Transects with Shoreline Change Rates (Post-1950s) (Geographic, NAD83) consists of vector transect data that were derived from the Digital Shoreline Analysis System (DSAS) version 4.0. Rates from the DSAS statistical output table were joined to the transects to provide a visual representation of the shoreline change rates on a transect-by-transect basis.
  1. How might this data set be cited?
    Terrano, Joseph F., Smith, Kathryn E., and Flocks, James G., 20160125, Breton Island, Louisiana Transects with Shoreline Change Rates (Post-1950s) (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: -89.220615
    East_Bounding_Coordinate: -89.147135
    North_Bounding_Coordinate: 29.508019
    South_Bounding_Coordinate: 29.453022
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 01-May-1950
    Ending_Date: 16-Jan-2014
    Currentness_Reference:
    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 (146)
    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 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?
    Breton_Transects_with_Rates_Post_1950s
    Transects with rate of change statistics for Breton Island from the Post-1950s analysis. (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
    TransOrder
    Value automatically assigned, by DSAS, to each transect in a sequential order and used for identification purposes. Values are missing if the line was removed, due to errors in earlier processing. (Source: USGS)
    Range of values
    Minimum:24
    Maximum:188
    StartX
    Starting X coordinate of each transect, in meters. (Source: USGS)
    Range of values
    Minimum:285262.6
    Maximum:291764.66
    StartY
    Starting Y coordinate of each transect, in meters. (Source: USGS)
    Range of values
    Minimum:3260228.88
    Maximum:3264467.43
    EndX
    End X coordinate of each transect, in meters. (Source: USGS)
    Range of values
    Minimum:284747.8
    Maximum:287096.28
    EndY
    End Y coordinate of each transect, in meters. (Source: USGS)
    Range of values
    Minimum:3265202.3
    Maximum:3266195.26
    Azimuth
    Azimuth of the transect measured in degrees clockwise of north. (Source: DSAS)
    Range of values
    Minimum:288.88
    Maximum:354.09
    EPR
    End Point Rate (Source: DSAS)
    Range of values
    Minimum:-15.52
    Maximum:19.42
    SCE
    Shoreline Change Envelope (Source: DSAS)
    Range of values
    Minimum:223.96
    Maximum:768.64
    NSM
    Net Shoreline Movement (Source: DSAS)
    Range of values
    Minimum:-740.95
    Maximum:558.75
    WLR
    Weighted Linear Regression. Attributes with a "-99999" value represent a null value. (Source: DSAS)
    Range of values
    Minimum:-99999
    Maximum:15.43
    LRR
    Linear Regression Rate. Attributes with a "-99999" value represent a null value. (Source: DSAS)
    Range of values
    Minimum:-99999
    Maximum:17.46
    SHAPE_Leng
    Length of feature in internal units. (Source: ESRI)
    Range of values
    Minimum:4999.99999588
    Maximum:5000.00000336

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 Coastal and Marine Science Center
    Attn: Joseph F. Terrano
    Researcher 1
    600 4th Street South
    St. Petersburg, Florida
    US

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

Why was the data set created?

Transect data are considered a crucial element in performing change analysis for erosion and accretion studies and for tracking shoreline movement over time. DSAS uses transects as a method to extract shoreline change rates from shorelines at a given interval across a baseline. For this long term analysis, transects were spaced out at a 50-m interval across the baseline, and shoreline change rates were calculated for the post Mississippi River Gulf Outlet (MRGO) (Pre-1950s ). Transect and rate attribute tables were joined to allow the rate values to be visualized on a map.

How was the data set created?

  1. From what previous works were the data drawn?
    Breton_DSAS_Transects_Post_1950s (source 1 of 1)
    Thieler, E.R., Himmelstoss, E.A., Zichichi, J.L., and Ergul, Ayhan, 2009, The Digital Shoreline Analysis System (DSAS) version 4.0—an ArcGIS Extension for Calculating Shoreline Change.

    Online Links:

    Type_of_Source_Media: Online
    Source_Scale_Denominator: 1500
    Source_Contribution: DSAS was used to generate the transects at a 50-m interval.
  2. How were the data generated, processed, and modified?
    Date: 01-Jun-2015 (process 1 of 2)
    A single transect file was created and 5 copies were created, one for each of the analysis time periods of: (1) 1869-2014 (long-term), (2) pre-1950s (before excavation of the MRGO), (3) post-1950s (post MRGO), (4) post-Hurricane Katrina (2005-2014) (short-term), and (5) pre/post Hurricane Katrina (2004-2005)(acute weather event). Transects were generated at a 50-meter interval perpendicular to the baseline and consisted of 211 transects. Transects were removed in areas where less than two shorelines were present. Rates of change were calculated for: (1) net shoreline movement (NSM); (2) shoreline change envelope (SCE); (3) end point rate (EPR); (4) linear regression rate (LRR), and (5) weighted linear regression rate (WLR) and saved to a table, in the ArcGIS personal geodatabase format. The rate table generated by DSAS was then joined to the respective transect file so the rate values could be displayed on a map. In joining the rates to the transect table, the WLR and LRR fields were not able to use a "null" value so null values are represented as a "-9999". These values should be checked and removed if using in any further analysis. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Joseph Terrano
    600 4th Street South
    St. Petersburg, Florida
    US

    (727) 502-8047 (voice)
    (727) 502-8001 (FAX)
    jterrano@usgs.gov
    Hours_of_Service:
    Monday through Friday, 9:00 a.m. to 5:00 p.m., Eastern Standard Time
    Date: 13-Oct-2020 (process 2 of 2)
    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)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?
    Thieler, E.R., Himmelstoss, E.A., Zichichi, J.L., and Ergul, Ayhan, 2009, The Digital Shoreline Analysis System (DSAS) version 4.0—an ArcGIS Extension for Calculating Shoreline Change.

    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?
    Transects with errors or no rate values for all statistic fields were removed to ensure that only valid rates of change were used in the analysis. Errors included "null" and "0" values, which represent a transect that crossed only 0 or 1 shoreline and skewed the results. When joining the rates to the transect attribute table, the WLR and LRR fields could not contain a "null" value so null values are represented as a "-99999". These values should be checked and removed if using in any further analysis. The remaining transects with rates were used to aid in the final shoreline change results.
  5. How consistent are the relationships among the observations, including topology?
    Transects were generated as a product of the DSAS program at a 50-m interval. These transects were checked to ensure an even distribution and coverage of the shoreline datasets.

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.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    Attn: James Flocks
    600 4th Street South
    St. Petersburg, Florida
    US

    (727) 502-8012 (voice)
    (727) 502-8001 (FAX)
    Hours_of_Service:
    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_Transects_with_Rates_Post_1950s.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?

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

(727) 502-8047 (voice)
(727) 502-8001 (FAX)
jterrano@usgs.gov
Hours_of_Service:
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/Post_1950s_Transect_Metadata.faq.html>
Generated by mp version 2.9.50 on Tue Sep 21 18:18:51 2021