Transect Lines for Assateague Island, Maryland and Virginia

Metadata also available as - [Outline] - [Parseable text] - [XML]

Frequently anticipated questions:

What does this data set describe?

Title: Transect Lines for Assateague Island, Maryland and Virginia
Abstract:
Assessing the physical change to shorelines and wetlands is critical in determining the resiliency of wetland systems that protect adjacent habitat and communities. The wetland and back-barrier shorelines of Assateague Island, located in Maryland and Virginia, changed as a result of wave action and storm surge that occurred during Hurricane Sandy, which made landfall on October 29, 2012. The impact of Hurricane Sandy will be assessed and placed in its historical context to understand the future vulnerability of wetland systems. Making these assessments will rely on data extracted from current and historical resources such as maps, aerial photographs, satellite imagery, and lidar elevation data, which document physical changes over time. This USGS Data Series publication includes several open-ocean shorelines, back-island shorelines, back-island shoreline points, sand area polygons, and sand lines for Assateague Island that were extracted from ortho imagery (ortho aerial photography)dated from April 12, 1989 to September 5, 2013.
  1. How might this data set be cited?
    U.S. Geological Survey, 2015, Transect Lines for Assateague Island, Maryland and Virginia: U.S. Geological Survey Data Series 928, U.S. Geological Survey, St. Petersburg, Fla..

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -75.425895
    East_Bounding_Coordinate: -75.077115
    North_Bounding_Coordinate: 38.357579
    South_Bounding_Coordinate: 37.842700
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2015
    Currentness_Reference:
    publication date
  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 (3024)
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 18
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -75.0
      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 North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System of 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?
    asis_transects_ln_20m_utm18.shp
    Transect lines used identify data collection points on Assateague Island. (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
    Unique sequential number automatically assigned by DSAS software. (Source: USGS)
    Range of values
    Minimum:1
    Maximum:10400
    StartX
    Transect starting point X coordinate in North American Datum of 1983, Geodetic Reference System of 1980, Universal Transverse Mercator zone 18N (NAD83 GRS1980 UTM z18N) in meters. (Source: NAD83 GRS1980 UTM z18N) varying value range
    StartY
    Transect starting point Y coordinate in NAD83 GRS1980 UTM z18N in meters. (Source: NAD83 GRS1980 UTM z18N) varying value range
    EndX
    Transect ending point X coordinate in NAD83 GRS1980 UTM z18N in meters. (Source: NAD83 GRS1980 UTM z18N) varying value range
    EndY
    Transect ending point Y coordinate in NAD83 GRS1980 UTM z18N in meters. (Source: NAD83 GRS1980 UTM z18N) varying value range
    Azimuth
    Direction, expressed in the angular distance from north, of the transect line from its starting point to its ending point, in degrees. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:359.99

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • U.S. Geological Survey
  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
    Attn: Kristy Guy
    600 4th St. S.
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    727-502-8181 (FAX)
    kguy@usgs.gov
    Hours_of_Service: Monday through Friday 9:00 AM to 5:00 PM (Eastern Time)

Why was the data set created?

This data set consists of digital transect lines that cross Assateague Island at 20 meter (m) intervals. They were created using off-shore, reference baselines that approximate the trend of the open-ocean shoreline of the island, and ArcGIS 10.1 and Digital Shoreline Analysis System (DSAS) software (USGS Open-File Report 2008-1278), which creates transects lines perpendicular to the baselines. The back-island shorelines and shoreline points included in this data series are based on the intersection of back-island shorelines and transect lines.

How was the data set created?

  1. From what previous works were the data drawn?
    asis_baselines_ln_utm18.shp (source 1 of 1)
    USGS, 2014, USGS Assateague Island Baselines: USGS, St. Petersburg, Fla..

    Type_of_Source_Media: digital
    Source_Contribution: Reference lines used to produce transects.
  2. How were the data generated, processed, and modified?
    Date: 2014 (process 1 of 3)
    Using Digital Shoreline Analysis System (DSAS) and ArcMap 10.1 software, transects were created from baselines at 20 m intervals. The resulting transect feature class was exported to a shapefile. Person who carried out this activity:
    USGS
    600 4th St. S.
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    727-502-8181 (FAX)
    Hours_of_Service: Monday through Friday 8:00 AM to 5:00 PM (Eastern Time)
    Contact_Instructions:
    If unable to reach the contact by telephone, please leave a voice message.
    Data sources used in this process:
    • Baselines
    Data sources produced in this process:
    • asis_transects_ln_20m_utm18.shp
    Date: 22-Mar-2018 (process 2 of 3)
    Keywords section of metadata optimized by adding theme keyword thesauri and associated keywords. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Arnell S. Forde
    Geologist
    600 4th Street South
    St. Petersburg, FL

    727-502-8000 (voice)
    aforde@usgs.gov
    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)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?

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?
    These transect lines do not correspond to any real-world features.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Complete.
  5. How consistent are the relationships among the observations, including topology?
    The transects are spaced at 20 m intervals and created from baselines that approximate the trend of the open-ocean island shoreline. They are numbered sequentially from south to north in the "TransOrder" field of the attribute.

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:
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center Coastal and Marine Geology Program as the originator of these data in future products or derivative research.
  1. Who distributes the data set? (Distributor 1 of 1)
    Kristy Guy
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, Fla.
    GIS/RS Analyst
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    Hours_of_Service: Monday-Friday, 9:00-5:00 Eastern Time
  2. What's the catalog number I need to order this data set? DS 928
  3. What legal disclaimers am I supposed to read?
    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.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: ArcGIS shapefile
      Network links: https://pubs.usgs.gov/ds/0928/downloads/baselines_transects.zip
    • Cost to order the data: None if obtained online; otherwise prices vary.

    • Special instructions:
      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).

Who wrote the metadata?

Dates:
Last modified: 13-Oct-2020
Metadata author:
USGS
Attn: Kristy Guy
600 4th Street South
St. Petersburg, FL
USA

727-502-8000 (voice)
727-502-8181 (FAX)
kguy@usgs.gov
Hours_of_Service: Monday through Friday 9:00 AM to 5:00 PM (Eastern Time)
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/DS928_asis_transects_ln_20m_utm18.faq.html>
Generated by mp version 2.9.50 on Tue Sep 21 18:18:48 2021