Digital Shoreline Analysis System version 4.3 transects and long-term linear regression shoreline change statistics for all data available within the Nantucket coastal region including the Nantucket Sound- and Atlantic Ocean- facing coasts of Nantucket, Muskeget and Tuckernuck Islands (Nantucket_transects_rates_LTw.shp)

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

Frequently anticipated questions:

What does this data set describe?

Title:
Digital Shoreline Analysis System version 4.3 transects and long-term linear regression shoreline change statistics for all data available within the Nantucket coastal region including the Nantucket Sound- and Atlantic Ocean- facing coasts of Nantucket, Muskeget and Tuckernuck Islands (Nantucket_transects_rates_LTw.shp)
Abstract:
Due to continued coastal population growth and increased threats of erosion, current data on trends and rates of shoreline movement are required to inform shoreline and floodplain management. The Massachusetts Office of Coastal Zone Management launched the Shoreline Change Project in 1989 to identify erosion-prone areas of the coast. In 2001, a 1994 shoreline was added to calculate both long- and short-term shoreline change rates at 40-meter intervals along ocean-facing sections of the Massachusetts coast.
The Coastal and Marine Geology Program of the U.S. Geological Survey (USGS) in cooperation with the Massachusetts Office of Coastal Zone Management, has compiled reliable historical shoreline data along open-facing sections of the Massachusetts coast under the Massachusetts Shoreline Change Mapping and Analysis Project 2013 Update. Two oceanfront shorelines for Massachusetts (approximately 1,800 km) were (1) delineated using 2008/09 color aerial orthoimagery, and (2) extracted from topographic LIDAR datasets (2007) obtained from NOAA's Ocean Service, Coastal Services Center. The new shorelines were integrated with existing Massachusetts Office of Coastal Zone Management and USGS historical shoreline data in order to compute long- and short-term rates using the latest version of the Digital Shoreline Analysis System (DSAS).
  1. How might this data set be cited?
    U.S. Geological Survey, 2013, Digital Shoreline Analysis System version 4.3 transects and long-term linear regression shoreline change statistics for all data available within the Nantucket coastal region including the Nantucket Sound- and Atlantic Ocean- facing coasts of Nantucket, Muskeget and Tuckernuck Islands (Nantucket_transects_rates_LTw.shp): Open-File Report 2012-1183, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Smith, Theresa L., Himmelstoss, Emily A., and Thieler, E. Robert, 2013, Massachusetts Shoreline Change Project: A GIS Compilation of Vector Shorelines and Associated Shoreline Change Data for the 2013 update: Open-File Report 2012-1183, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.320698
    East_Bounding_Coordinate: -69.959012
    North_Bounding_Coordinate: 41.393014
    South_Bounding_Coordinate: 41.236735
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2013
    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 (2227)
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.
  7. How does the data set describe geographic features?
    Nantucket_transects_rates_LTw
    Measurement transects and resulting long-term linear regression rate calculations (Source: U.S. Geological Survey)
    FID
    Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: Esri) Coordinates defining the features.
    OBJECTID
    Internal feature number used within geodatabase. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    BaselineID
    Unique identification number of the baseline segment. If BaselineID=0 no transects will be generated. Used by DSAS to determine transect ordering alongshore if multiple baseline segments exist. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:unlimited
    TransOrder
    Assigned by DSAS on the basis of transect order along the baseline or baselines. This field provides the user with a method to sort transect data from the start of the baseline segment with an ID=1 and increment sequentially to the end of the final baseline segment. (Source: U.S. Geological Survey)
    Range of values
    Minimum:1
    Maximum:2227
    StartX
    Assigned by DSAS automatically to record the X coordinate of the beginning of the transect in meter units (State Plane Masachusetts Mainland FIPS 2001, NAD 83). (Source: U.S. Geological Survey) Values based on data set extent.
    StartY
    Assigned by DSAS automatically to record the Y coordinate of the beginning of the transect in meter units (State Plane Masachusetts Mainland FIPS 2001, NAD 83). (Source: U.S. Geological Survey) Values based on data set extent.
    EndX
    Assigned by DSAS automatically to record the X coordinate of the end of the transect in meter units (State Plane Masachusetts Mainland FIPS 2001, NAD 83). (Source: U.S. Geological Survey) Values based on data set extent.
    EndY
    Assigned by DSAS automatically to record the Y coordinate of the end of the transect in meter units (State Plane Masachusetts Mainland FIPS 2001, NAD 83). (Source: U.S. Geological Survey) Values based on data set extent.
    Azimuth
    Assigned by DSAS to record the azimuth of the transect measure in degrees clockwise from North. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:360
    TransectId
    Same value as ObjectID. Used as a permanent and unique identification number for each transect in the output rates table calculated by DSAS. This attribute was used as the common field when joining the rates table (.dbf) to the transect feature class in a geodatabase. (Source: U.S. Geological Survey) Positive real numbers that are automatically generated.
    SCE
    Shoreline Change Envelope the distance in meters (State Plane Masachusetts Mainland FIPS 2001, NAD 83) calculated by DSAS between the shoreline farthest from and closest to the baseline. (Source: U.S. Geological Survey)
    Range of values
    Minimum:6.19
    Maximum:1180.06
    NSM
    Net Shoreline Movement - the distance in meters (State Plane Masachusetts Mainland FIPS 2001, NAD 83) calculated by DSAS between the oldest and youngest shorelines for each transect. If negative, the youngest shoreline is landward of the oldest (erosional), if positive, the youngest is seaward of the oldest (accretional). (Source: U.S. Geological Survey)
    Range of values
    Minimum:-976
    Maximum:616.82
    Shape_Leng
    Length of feature in meter units (State Plane Masachusetts Mainland FIPS 2001, NAD 83). (Source: U.S. Geological Survey)
    Range of values
    Minimum:34.961167
    Maximum:1239.535588
    LRR
    Linear Regression Rate- A linear regression rate-of-change statistic was calculated by fitting a least-squares regression line to all shoreline points for a particular transect. The best-fit regression line is placed so that the sum of the squared residuals (determined by squaring the offset distance of each data point from the regression line and adding the squared residuals together) is minimized. The linear regression rate is the slope of the best-fit line. The rate is reported in meters per year with positive values indicating accretion and negative values indicating erosion. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-7.15
    Maximum:4.28
    LR2
    R-squared statistic, or coefficient of determination of linear regression, is the variance in the data calculated by DSAS that is explained by a regression. It is a dimensionless statistic that ranges from 1.0 to 0.0 and measure how successfully the best-fit line accounts for variation in the data. R-squared values close to 1.0 imply that the best-fit line explains most of the variation in the dependent variable. R-squared values close to 0.0 implies that the best-fit line explains little of the variation in the dependent variable and may not be a useful model. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:1
    LSE
    The predicted (or estimated) values of y (the distance from baseline in meters) are computed for each shoreline point by using the values of x (the shoreline date) and solving the equation for the best-fit regression line (y=mx+b). The standard error is also called the standard deviation. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.87
    Maximum:282.95
    LCI90
    The standard error of the slope with confidence interval describes the uncertainty of the reported rate. The LRR rates are determined by a best-fit regression line for the shoreline data at each transect. The slope of this line is the reported rate of change (in meters/year). The confidence interval (LCI) is calculated by multiplying the standard error (also called the standard deviation) of the slope by the two-tailed test statistic at the user-specified 90 percent confidence. This value is often reported in conjunction with the slope to describe the confidence of the reported rate. For example: LRR = 1.2 LCI90 = 0.7 could be reported as a rate of 1.2 (+/-) 0.7 meters/year. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.015
    Maximum:5.968

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?
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Theresa Smith
    Contract Geologist
    384 Woods Hole Road
    Woods Hole, MA
    USA

    508-548-8700 (voice)
    508-457-2310 (FAX)
    theresasmith@usgs.gov

Why was the data set created?

This dataset consists of long-term (100+ years) linear regression shoreline change rates for the Nantucket region of Massachusetts. Rates of long-term shoreline change were computed within a GIS using the Digital Shoreline Analysis System (DSAS) version 4.3, an ArcGIS extension developed by the U.S. Geological Survey. The baseline is used as a reference line for the transects cast by the DSAS software. The transects intersect each shoreline at the measurement points, which are then used to calculate a linear regression rate for the Massachusetts Office of Coastal Zone Management Shoreline Change Project. Long-term linear regression statistics were calculated with all of the historical shorelines compiled for the Massachusetts Office of Coastal Zone Management Shoreline Change Project.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 19-Sep-2011 (process 1 of 12)
    Transect Features Generated using DSAS v.4.2 in ArcGIS 9.3. Parameters Used: baseline layer=Nantucket_baseline, baseline group field=NULL, transect spacing=50 meters, transect length=200 meters, cast direction=AUTO-DETECT, baseline location=on/off shore, cast method=smoothed baseline, smoothing distance=250 meters, flip baselines=not selected. For additional details on these parameters, please see the DSAS help file distributed with the DSAS software, or visit the USGS website at: https://pubs.er.usgs.gov/publication/ofr20081278.
    This process step and all subsequent process steps were performed by Theresa Smith. Person who carried out this activity:
    Theresa Smith
    U.S. Geological Survey
    Contract Geologist
    384 Woods Hole Road
    Woods Hole, MA
    USA

    508-548-8700 (voice)
    508-457-2310 (FAX)
    theresasmith@usgs.gov
    Date: 19-Sep-2011 (process 2 of 12)
    After transects were generated, it was sometimes necessary to modify their length using standard editing tools in ArcMap v9.3 so that they intersected the shoreline data needed for analysis. In some cases sections of the baseline were modified using the dynamic topology in DSAS that allows edits to the baseline in a standard ArcMap (v9.3) editing session to update the position of transects if the transect field is enabled as the target layer in the DSAS (v4.2) toolbar.
    Date: 06-Feb-2012 (process 3 of 12)
    After transects were generated, the entire geodatabase was upgraded to v.10 by right-clicking on the geodatabase and choosing Properties from the pop-up window in ArcCatalog v.10. The Upgrade Geodatabase button was clicked at the bottom of the General tab in the Database Properties window.
    Date: 12-Oct-2012 (process 4 of 12)
    Rate Calculations Performed using DSAS v.4.3 for ArcMap v.10. Parameters Used: shoreline layer=Nantucket_shorelines, shoreline date field=Date_, shoreline uncertainty field name=Uncy (additional shoreline data stored in Nantucket_shorelines_uncertainty.dbf), the default accuracy=10.8 meters, shoreline intersection parameters=nearest, stats calculations=[Shoreline Change Envelope (SCE), Net Shoreline Movement (NSM), Linear Regression Rate (LRR)], shoreline threshold=3, confidence interval=90%, Output rate table name=Nantucket_transects_rates_20121012_154822.dbf.
    Date: 12-Oct-2012 (process 5 of 12)
    The shoreline rates output table (Nantucket_transects_rates_20121012_154822.dbf) was joined to the transect feature class in ArcMap v.10 by right-clicking on the transect layer > joins and relates > join > join attributes from a table. Parameters: join field - ObjectID; table to join - Nantucket_transects_rates_20121012_154822; field in table: TransectID; join options - keep only matching records.
    Date: 12-Oct-2012 (process 6 of 12)
    The joined data were exported to a shapefile in ArcMap v.10 by right-clicking the transect file, choosing data > export data. The new shapefile was named Nantucket_transects_rates_LTw.shp and permanently adds the joined rate fields to the transect attribute table.
    Date: 12-Nov-2012 (process 7 of 12)
    Due to the lack of continuous long-term shoreline position data, some transects intersected shorelines from 1970-2009, but did not intersect shorelines prior to 1970, which resulted in long-term linear regression rates that were identical to short-term linear regression rates. A filter was applied to the transect/rates data in ArcMap v10: 1) Select by Attributes > create new selection: SELECT FROM MA_shorelines.shp WHERE [Year] >=1970; and 2) Select by Location, Target layer: Nantucket_transects_rates_LTw.shp, Source layer: MA_shorelines.shp, parameters: use selected features spatial selection method: Target layer(s) features intersect the source layer feature). Transects that did not intersect long-term shoreline data (1844-1960) were deleted in a standard editing session (ArcMAP v10).
    Date: 16-Nov-2012 (process 8 of 12)
    The exported transect shapefile was projected in Esri's ArcToolbox (v.10) > Data Management Tools > Projections and Transformations > Feature > Project. Parameters: input projection - NAD_1983_StatePlane_Massachusetts_Mainland_FIPS_2001; output projection - geographic coordinates (NAD83); transformation - none.
    Date: 11-Oct-2017 (process 9 of 12)
    Edits to the metadata were made to fix any errors that MP v 2.9.36 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). Attempted to modify http to https where appropriate. Added a landing page link as the first link in the identification section. Fixed online link to DSAS cross-reference. The distribution format name was modified in an attempt to be more consistent with other metadata files of the same data format. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent. 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
    Date: 20-Jul-2018 (process 10 of 12)
    USGS Thesaurus keywords added to the keyword section. 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
    Date: 18-Nov-2019 (process 11 of 12)
    Crossref DOI link was added as the first link in the metadata. 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
    Date: 08-Sep-2020 (process 12 of 12)
    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., Smith, T.L., Knisel, Julia, and Sampson, D.W., 2013, Massachusetts Shoreline Change Mapping and Analysis Project, 2013 Update: Open-File Report 2012-1189, U.S. Geological Survey, Reston, VA.

    Online Links:

    Thieler, E.R., Himmelstoss, E.A., Zichichi, J.L., and Ergul, A., 2009, Digital Shoreline Analysis System (DSAS) version 4.0: an ArcGIS extension for calculating shoreline change: Open-File Report 2008-1278, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details: Current version is 4.3
    Thieler, E. Robert, O'Connell, James F., and Schupp, Courtney A., 20010904, The Massachusetts Shoreline Change Project: 1800s to 1994 Technical Report: U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details: Administrative Report

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

  1. How well have the observations been checked?
    The attributes of this dataset are based on the field requirements of the Digital Shoreline Analysis System and were automatically generated by the software during the generation of the transect layer or during the calculation of shoreline change rates performed by the software.
  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?
    This dataset contains the transects automatically generated by the DSAS software application that were used to calculate long-term shoreline change rates for the region. Additional transects may have been generated but did not intersect the minimum requirement of three shorelines to calculate linear regression long-term rates. These data are part of a state-wide assessment of shoreline change that includes over 26,500 individual transect locations that were used to compute both short- and long-term rates of change, based on almost 9200 linear kilometers of historical shoreline position data. It is very likely that some gross errors or blunders were introduced during compilation and analysis of this large amount of information. Such errors have been described in the context of shoreline change mapping as coarse errors (Fenster and others, 2001) and can generally be considered to affect only a very small percentage of the overall dataset.
    Fenster, M.S., Dolan, R., and Morton, R.A., 2001, Coastal storms and shoreline change: signal or noise?: Journal of Coastal Research, v. 17, no. 3, p. 714-720.
  5. How consistent are the relationships among the observations, including topology?
    These transect data were generated using DSAS v.4.2 and the rates were calculated using DSAS v.4.3, an automated software program which does not perform checks for fidelity of the input features. The transects were visually inspected and sometimes manually adjusted within a standard ArcMap edit session to adjust the position at which an individual transect intersected the shorelines.

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:
These data were automatically generated using the DSAS versions 4.2 (transects) and 4.3 (rates) software applications and should only be used for purposes explicitly stated by the originating organization. Please recognize the U.S. Geological Survey (USGS) and the Massachusetts Office of Coastal Zone Management as the originators of this dataset.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    384 Woods Hole Road
    Woods Hole, MA
    USA

    508-548-8700 (voice)
    508-457-2310 (FAX)
  2. What's the catalog number I need to order this data set? Downloadable data.
  3. What legal disclaimers am I supposed to read?
    Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials.
    Any use of trade, product, or firm 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: This WinZip (version 14) file contains a shapefile of transects generated by the Digital Shoreline Analysis System including long-term linear regression rate calculations for the Nantucket region of Massachusetts. Metadata is also included. in format Shapefile (version ArcGIS 10) Esri polyline shapefile Size: 1
      Network links: https://pubs.usgs.gov/of/2012/1183/data/Nantucket/Nantucket_transects_rates_LTw.zip
    • Cost to order the data: None

  5. What hardware or software do I need in order to use the data set?
    This zip file contains data available in Environmental Systems Research Institute (Esri) polyline shapefile format. The user must have ArcGIS or ArcView 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing the data. A free data viewer, ArcExplorer, capable of displaying the data is available from Esri at www.esri.com.

Who wrote the metadata?

Dates:
Last modified: 16-Nov-2021
Metadata author:
Theresa Smith
U.S. Geological Survey
Contract Geologist
384 Woods Hole Road
Woods Hole, MA
USA

508-548-8700 (voice)
508-457-2310 (FAX)
whsc_data_contact@usgs.gov
Contact_Instructions:
The metadata contact email address is a generic address in the event the metadata contact is no longer with the USGS or the email is otherwise invalid.
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/open_file_report/ofr2012-1183/Nantucket_transects_rates_LTw.shp.xml.faq.html>
Generated by mp version 2.9.50 on Tue Nov 16 10:06:49 2021