Long-term and short-term shoreline change rates for the region of Martha's Vineyard, Massachusetts, calculated with and without the proxy-datum bias using the Digital Shoreline Analysis System version 5.1

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Title:
Long-term and short-term shoreline change rates for the region of Martha's Vineyard, Massachusetts, calculated with and without the proxy-datum bias using the Digital Shoreline Analysis System version 5.1
Abstract:
The Massachusetts Office of Coastal Zone Management launched the Shoreline Change Project in 1989 to identify erosion-prone areas of the coast and support local land-use decisions. Trends of shoreline position over long and short-term timescales provide information to landowners, managers, and potential buyers about possible future impacts to coastal resources and infrastructure. In 2001, a 1994 shoreline was added to calculate both long- and short-term shoreline change rates along ocean-facing sections of the Massachusetts coast. In 2013 two oceanfront shorelines for Massachusetts were added using 2008-2009 color aerial orthoimagery and 2007 topographic lidar datasets obtained from NOAA's Ocean Service, Coastal Services Center. In 2018, two new mean high water (MHW) shorelines for the Massachusetts coast extracted from lidar data between 2010-2014 were added to the dataset. This 2021 data release includes rates that incorporate one new shoreline extracted from 2018 lidar data collected by the U.S. Army Corps of Engineers (USACE) Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBTCX), added to the existing database of all historical shorelines (1844-2014), for the North Shore, South Shore, Cape Cod Bay, Outer Cape, Buzzard’s Bay, South Cape, Nantucket, and Martha’s Vineyard. 2018 lidar data did not cover the Boston or Elizabeth Islands regions. Included in this data release is a proxy-datum bias reference line that accounts for the positional difference in a proxy shoreline (like a High Water Line shoreline) and a datum shoreline (like a Mean High Water shoreline. This issue is explained further in Ruggiero and List (2009) and in the process steps of the metadata associated with the rates. This release includes both long-term (~150+ years) and short term (~30 years) rates. Files associated with the long-term rates have "LT"; in their names, files associated with short-term rates have "ST"; in their names.
  1. How might this data set be cited?
    U.S. Geological Survey, 20210831, Long-term and short-term shoreline change rates for the region of Martha's Vineyard, Massachusetts, calculated with and without the proxy-datum bias using the Digital Shoreline Analysis System version 5.1: Data release doi:10.5066/P9YGIYFX, 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.

    Bartlett, Marie K., Henderson, Rachel E., Farris, Amy S., and Himmelstoss, Emily A., 2021, Massachusetts Shoreline Change Project, 2021 Update: A GIS Compilation of Shoreline Change Rates Calculated Using Digital Shoreline Analysis System Version 5.1, With Supplementary Intersects and Baselines for Massachusetts: Data release doi:10.5066/P9YGIYFX, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    suggested citation: Bartlett, M.K., Henderson, R. E., Farris, A.S., and Himmelstoss, E.A., 2021, Massachusetts shoreline change project, 2021 update–A GIS compilation of shoreline change rates calculated using Digital Shoreline Analysis System version 5.1, with supplementary intersects and baselines for Massachusetts: U.S. Geological Survey data release. https://doi.org/10.5066/P9YGIYFX
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.8390
    East_Bounding_Coordinate: -70.4463
    North_Bounding_Coordinate: 41.4827
    South_Bounding_Coordinate: 41.2490
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/610829f2d34ef8d70565ba19?name=MarthasVineyard_rates_browse.PNG (PNG)
    Map view of data
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2021
    Currentness_Reference:
    ground condition of the most recent shoreline these rates are based on
  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
    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 0.0197422351. Longitudes are given to the nearest 0.0261997981. Latitude and longitude values are specified in Decimal seconds. The horizontal datum used is D WGS 1984.
      The ellipsoid used is WGS 1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    MarthasVN_rates_LT.shp
    Rates of long-term shoreline change are calculated by DSAS and stored in the transect file, using the distance measurements between shorelines and baseline at each DSAS transect. These attributes are for long-term rates with and without bias applied. The shapefiles will have LT for long-term in filename. Vector Object Count: 1404 (Source: U.S. Geological Survey)
    FID
    Internal feature number used as a unique identifier of an object within a table primarily used in shapefiles. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    SHAPE
    Feature geometry (Source: Esri) Coordinates defining the features.
    TransectID
    A unique identification number for each transect. Values may not increment sequentially alongshore. (Source: U.S. Geological Survey) 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:1
    Maximum:unlimited
    GroupID
    This optional field is a way to aggregate transects on the basis of physical variations alongshore (for example, tidal inlets, change in coastal type, or hard stabilization features). This value was assigned by the user as an attribute to a baseline segment and results in a group average being reported in the DSAS summary text file. (Source: U.S. Geological Survey)
    Range of values
    Minimum:1
    Maximum:unlimited
    TransOrder
    Assigned by DSAS based on ordering of transects along the baseline. Used to allow user to sort transect data along the baseline from baseline start to baseline end. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:unlimited
    Azimuth
    Assigned by DSAS to record the azimuth of the transect measure in degrees clockwise from North. If a transect position has been adjusted during the editing process, the azimuth value in the attribute table is updated automatically. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:360
    Units:Degrees
    ShrCount
    Number of shorelines used to compute shoreline change metrics. (Source: U.S. Geological Survey)
    Range of values
    Minimum:3
    Maximum:unlimited
    TCD
    The Total Cumulative Distance (TCD) is the measure in meters along shore from the start of the baseline segment with an ID=1, and measured sequentially alongshore to the end of the final baseline segment (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:unlimited
    SHAPE_Length
    Length of feature in meter units (UTM zone 19N, WGS 84) (Source: Esri)
    Range of values
    Minimum:0
    Maximum:unlimited
    LRR
    A linear regression rate-of-change statistic was calculated by fitting a least-squares regression line to all shoreline points for a particular transect. Any shoreline points that are referenced to HWL were adjusted by the proxy-datum bias distance (meters) along the transect to correct for the offset between proxy-based HWL and datum-based MHW shorelines. 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 line. The rate is reported in meters per year with positive values indicating accretion and negative values indicating erosion. LRR calculations require a minimum of 3 shorelines; less than 3 shorelines results in a “null” value, which is not a supported value in shapefile format . A value of 9999 in the LRR attribute field along with a ShRCount of 2 indicates the required number of shorelines to compute the linear regression rate was not met. (Source: U.S. Geological Survey) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin. Reported in meters per year.
    NB_LRR
    The LRR without the bias applied. (Source: U.S. Geological Survey) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin. Reported in meters per year.
    LR2
    The R-squared statistic, or coefficient of determination, is the percentage of variance in the data that is explained by a regression. It is a dimensionless index that ranges from 1.0 to 0.0 and measures how successfully the best-fit line accounts for variation in the data. The smaller the variability of the residual values around the regression line relative to the overall variability, the better the prediction (and closer the R-squared value is to 1.0). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:1
    NB_LR2
    The LR2 without the bias applied. (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) Positive decimal values in meters.
    NB_LSE
    The LSE without the bias applied. (Source: U.S. Geological Survey) Positive decimal values in meters.
    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) Positive decimal values in meters
    NB_LCI90
    The LCI at the user-selected confidence value without the bias applied. (Source: U.S. Geological Survey) Positive decimal values in meters
    MarthasVN_rates_ST.shp
    Rates of short-term shoreline change are calculated by DSAS and stored in the transect file, using the distance measurements between shorelines and baseline at each DSAS transect. These attributes are for short-term rates with and without bias applied. The shapefiles will have ST for short-term in filename. Vector object count: 1400 (Source: U.S. Geological Survey)
    FID
    Internal feature number used as a unique identifier of an object within a table primarily used in shapefiles. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: ESRI) Coordinates defining the features.
    TransectID
    A unique identification number for each transect. Values may not increment sequentially alongshore. (Source: USGS) 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: USGS)
    Range of values
    Minimum:1
    Maximum:unlimited
    GroupID
    This optional field is a way to aggregate transects on the basis of physical variations alongshore (for example, tidal inlets, change in coastal type, or hard stabilization features). This value was assigned by the user as an attribute to a baseline segment and results in a group average being reported in the DSAS summary text file. (Source: USGS)
    Range of values
    Minimum:1
    Maximum:unlimited
    TransOrder
    Assigned by DSAS based on ordering of transects along the baseline. Used to allow user to sort transect data along the baseline from baseline start to baseline end. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:unlimited
    Azimuth
    Assigned by DSAS to record the azimuth of the transect measure in degrees clockwise from North. If a transect position has been adjusted during the editing process, the azimuth value in the attribute table is updated automatically. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:360
    ShrCount
    Number of shorelines used to compute shoreline change metrics. (Source: USGS)
    Range of values
    Minimum:2
    Maximum:unlimited
    TCD
    The Total Cumulative Distance (TCD) is the measure in meters along shore from the start of the baseline segment with an ID=1, and measured sequentially alongshore to the end of the final baseline segment (Source: USGS)
    Range of values
    Minimum:0
    Maximum:unlimited
    EPR
    The end point rate (EPR) is calculated by determining the distance between the oldest and youngest shoreline on a DSAS transect and dividing by the time elapsed between the two shoreline dates. (Source: U.S. Geological Survey) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin. Reported in meters per year.
    NB_EPR
    EPR without the bias applied. (Source: U.S. Geological Survey) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin. Reported in meters per year.
    EPRunc
    An estimate of end point rate uncertainty. The shoreline uncertainties for the two positions used in the end point calculation are each squared, then added together (summation of squares). The square root of the summation of squares is divided by the number of years between the two shorelines. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:unlimited
    NB_EPRunc
    EPRunc without the bias applied. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:unlimited
    LRR
    A linear regression rate-of-change statistic was calculated by fitting a least-squares regression line to all shoreline points for a particular transect. Any shoreline points that are referenced to HWL were adjusted by the proxy-datum bias distance (meters) along the transect to correct for the offset between proxy-based HWL and datum-based MHW shorelines. 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 line. The rate is reported in meters per year with positive values indicating accretion and negative values indicating erosion. LRR calculations require a minimum of 3 shorelines; less than 3 shorelines results in a “null” value, which is not a supported value in shapefile format . A value of 9999 in the LRR attribute field along with a ShRCount of 2 indicates the required number of shorelines to compute the linear regression rate was not met. (Source: USGS) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin. Reported in meters per year.
    NB_LRR
    LRR without the bias applied. (Source: USGS) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin. Reported in meters per year.
    LR2
    The R-squared statistic, or coefficient of determination, is the percentage of variance in the data that is explained by a regression. It is a dimensionless index that ranges from 1.0 to 0.0 and measures how successfully the best-fit line accounts for variation in the data. The smaller the variability of the residual values around the regression line relative to the overall variability, the better the prediction (and closer the R-squared value is to 1.0). (Source: USGS)
    Range of values
    Minimum:0
    Maximum:1
    NB_LR2
    LR2 without the bias applied (Source: USGS)
    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: USGS) Positive decimal values in meters.
    NB_LSE
    LSE without the bias applied. (Source: USGS) Positive decimal values in meters.
    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: USGS) Positive decimal values in meters.
    NB_LCI90
    LC190 without the bias applied. (Source: USGS) Positive decimal values in meters.
    SHAPE_Leng
    Length of feature in meter units (UTM zone 19N, WGS 84) (Source: USGS)
    Range of values
    Minimum:0
    Maximum:unlimited
    MarthasVS_rates_LT.shp
    Rates of long-term shoreline change are calculated by DSAS and stored in the transect file, using the distance measurements between shorelines and baseline at each DSAS transect. These attributes are for long-term rates with and without bias applied. The shapefiles will have LT for short-term in filename. Vector object count: 1041 (Source: U.S. Geological Survey)
    FID
    Internal feature number used as a unique identifier of an object within a table primarily used in shapefiles. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: ESRI) Coordinates defining the features.
    TransectID
    A unique identification number for each transect. Values may not increment sequentially alongshore. (Source: USGS) 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: USGS)
    Range of values
    Minimum:1
    Maximum:unlimited
    GroupID
    This optional field is a way to aggregate transects on the basis of physical variations alongshore (for example, tidal inlets, change in coastal type, or hard stabilization features). This value was assigned by the user as an attribute to a baseline segment and results in a group average being reported in the DSAS summary text file. (Source: USGS)
    Range of values
    Minimum:1
    Maximum:unlimited
    TransOrder
    Assigned by DSAS based on ordering of transects along the baseline. Used to allow user to sort transect data along the baseline from baseline start to baseline end. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:unlimited
    Azimuth
    Assigned by DSAS to record the azimuth of the transect measure in degrees clockwise from North. If a transect position has been adjusted during the editing process, the azimuth value in the attribute table is updated automatically. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:360
    ShrCount
    Number of shorelines used to compute shoreline change metrics. (Source: USGS)
    Range of values
    Minimum:2
    Maximum:unlimited
    TCD
    The Total Cumulative Distance (TCD) is the measure in meters along shore from the start of the baseline segment with an ID=1, and measured sequentially alongshore to the end of the final baseline segment (Source: USGS)
    Range of values
    Minimum:0
    Maximum:unlimited
    LRR
    A linear regression rate-of-change statistic was calculated by fitting a least-squares regression line to all shoreline points for a particular transect. Any shoreline points that are referenced to HWL were adjusted by the proxy-datum bias distance (meters) along the transect to correct for the offset between proxy-based HWL and datum-based MHW shorelines. 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 line. The rate is reported in meters per year with positive values indicating accretion and negative values indicating erosion. LRR calculations require a minimum of 3 shorelines; less than 3 shorelines results in a “null” value, which is not a supported value in shapefile format . A value of 9999 in the LRR attribute field along with a ShRCount of 2 indicates the required number of shorelines to compute the linear regression rate was not met. (Source: USGS) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin. Reported in meters per year.
    NB_LRR
    LRR without the bias applied. (Source: USGS) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin. Reported in meters per year.
    LR2
    The R-squared statistic, or coefficient of determination, is the percentage of variance in the data that is explained by a regression. It is a dimensionless index that ranges from 1.0 to 0.0 and measures how successfully the best-fit line accounts for variation in the data. The smaller the variability of the residual values around the regression line relative to the overall variability, the better the prediction (and closer the R-squared value is to 1.0). (Source: USGS)
    Range of values
    Minimum:0
    Maximum:1
    NB_LR2
    LR2 without the bias applied (Source: USGS)
    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: USGS) Positive decimal values in meters.
    NB_LSE
    LSE without the bias applied. (Source: USGS) Positive decimal values in meters.
    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: USGS) Positive decimal values in meters.
    NB_LCI90
    LC190 without the bias applied. (Source: USGS) Positive decimal values in meters.
    SHAPE_Leng
    Length of feature in meter units (UTM zone 19N, WGS 84) (Source: USGS)
    Range of values
    Minimum:0
    Maximum:unlimited
    MarthasVS_rates_ST.shp
    Rates of short-term shoreline change are calculated by DSAS and stored in the transect file, using the distance measurements between shorelines and baseline at each DSAS transect. These attributes are for short-term rates with and without bias applied. The shapefiles will have ST for short-term in filename. Vector object count: 1041 (Source: U.S. Geological Survey)
    FID
    Internal feature number used as a unique identifier of an object within a table primarily used in shapefiles. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: ESRI) Coordinates defining the features.
    TransectID
    A unique identification number for each transect. Values may not increment sequentially alongshore. (Source: USGS) 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: USGS)
    Range of values
    Minimum:1
    Maximum:unlimited
    GroupID
    This optional field is a way to aggregate transects on the basis of physical variations alongshore (for example, tidal inlets, change in coastal type, or hard stabilization features). This value was assigned by the user as an attribute to a baseline segment and results in a group average being reported in the DSAS summary text file. (Source: USGS)
    Range of values
    Minimum:1
    Maximum:unlimited
    TransOrder
    Assigned by DSAS based on ordering of transects along the baseline. Used to allow user to sort transect data along the baseline from baseline start to baseline end. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:unlimited
    Azimuth
    Assigned by DSAS to record the azimuth of the transect measure in degrees clockwise from North. If a transect position has been adjusted during the editing process, the azimuth value in the attribute table is updated automatically. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:360
    ShrCount
    Number of shorelines used to compute shoreline change metrics. (Source: USGS)
    Range of values
    Minimum:2
    Maximum:unlimited
    TCD
    The Total Cumulative Distance (TCD) is the measure in meters along shore from the start of the baseline segment with an ID=1, and measured sequentially alongshore to the end of the final baseline segment (Source: USGS)
    Range of values
    Minimum:0
    Maximum:unlimited
    EPR
    The end point rate (EPR) is calculated by determining the distance between the oldest and youngest shoreline on a DSAS transect and dividing by the time elapsed between the two shoreline dates. (Source: U.S. Geological Survey) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin. Reported in meters per year.
    NB_EPR
    EPR without the bias applied. (Source: U.S. Geological Survey) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin. Reported in meters per year.
    EPRunc
    An estimate of end point rate uncertainty. The shoreline uncertainties for the two positions used in the end point calculation are each squared, then added together (summation of squares). The square root of the summation of squares is divided by the number of years between the two shorelines. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:unlimited
    NB_EPRunc
    EPRunc without the bias applied. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:unlimited
    LRR
    A linear regression rate-of-change statistic was calculated by fitting a least-squares regression line to all shoreline points for a particular transect. Any shoreline points that are referenced to HWL were adjusted by the proxy-datum bias distance (meters) along the transect to correct for the offset between proxy-based HWL and datum-based MHW shorelines. 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 line. The rate is reported in meters per year with positive values indicating accretion and negative values indicating erosion. LRR calculations require a minimum of 3 shorelines; less than 3 shorelines results in a “null” value, which is not a supported value in shapefile format . A value of 9999 in the LRR attribute field along with a ShRCount of 2 indicates the required number of shorelines to compute the linear regression rate was not met. (Source: USGS) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin. Reported in meters per year.
    NB_LRR
    LRR without the bias applied. (Source: USGS) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin. Reported in meters per year.
    LR2
    The R-squared statistic, or coefficient of determination, is the percentage of variance in the data that is explained by a regression. It is a dimensionless index that ranges from 1.0 to 0.0 and measures how successfully the best-fit line accounts for variation in the data. The smaller the variability of the residual values around the regression line relative to the overall variability, the better the prediction (and closer the R-squared value is to 1.0). (Source: USGS)
    Range of values
    Minimum:0
    Maximum:1
    NB_LR2
    LR2 without the bias applied (Source: USGS)
    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: USGS) Positive decimal values in meters.
    NB_LSE
    LSE without the bias applied. (Source: USGS) Positive decimal values in meters.
    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: USGS) Positive decimal values in meters.
    NB_LCI90
    LC190 without the bias applied. (Source: USGS) Positive decimal values in meters.
    SHAPE_Leng
    Length of feature in meter units (UTM zone 19N, WGS 84) (Source: USGS)
    Range of values
    Minimum:0
    Maximum:unlimited
    Entity_and_Attribute_Overview:
    The entity and attribute information provided here describes the tabular data associated with long-term (greater than 50 years, and typically closer to 100 years) and short-term (approximately 30 years) shoreline change rates. Rate statistics are presented with and without the proxy-datum bias, distinguished by fields containing “NB_” for “no bias” in the attribute table. Please review the individual attribute descriptions for detailed information. All calculations for length are in meter units and were based on the UTM zone 19N WGS 84 projection. This region has two shapefiles describing rates, long-term (150+ years) and short-term (~30 years).
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey - ScienceBase

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?
    Marie K. Bartlett
    USGS
    Geologist
    384 Woods Hole Rd
    Woods Hole, MA
    USA

    508-548-8700 x2306 (voice)
    508-547-2310 (FAX)
    mbartlett@usgs.gov

Why was the data set created?

This dataset describes the long-term (~150+ years) and short-term (~30 years) shoreline change rates for the Martha's Vineyard, MA coastal region. Rate calculations were computed within a GIS using the Digital Shoreline Analysis System (DSAS) version 5.1, an ArcGIS extension developed by the U.S. Geological Survey. Long-term and short-term rates of shoreline change were calculated using a linear regression rate based on available shoreline data. A reference baseline was used as the originating point for the orthogonal transects cast by the DSAS software. The transects intersect each shoreline establishing measurement points, which are then used to calculate rates. This dataset consists of shoreline change rates calculated with DSAS v5.1 and stored as a new transect layer. Original measurement transects are cast by DSAS from the baseline to intersect shoreline vectors, and the intersect data provide location and time information used to calculate rates of change

How was the data set created?

  1. From what previous works were the data drawn?
    MA 1844 - 2018 Shorelines (source 1 of 3)
    Bartlett, Marie K., Farris, Amy S., Weber, Kathryn M., and Himmelstoss, Emily A., 2021, Massachusetts Shoreline Change Project: A GIS Compilation of Vector Shorelines (1844-2018): data release doi:10.5066/P9O8QA8N, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Bartlett, M.K., Farris, A.S., and Weber, K.M., Himmelstoss, E.A., 2021, Massachusetts shoreline change project—A GIS compilation of vector shorelines (1844-2018): U.S. Geological Survey data release
    Type_of_Source_Media: vector digital data
    Source_Contribution:
    Shorelines published as part of the Massachusetts Shoreline Change Project, 2021 Update were compiled for shoreline change analysis with DSAS v5.1
    MarthasVN_baseline (source 2 of 3)
    Bartlett, Marie K., Henderson, Rachel E., Farris, Amy S., and Himmelstoss, Emily A., 2021, Baseline for the northern coast of Martha's Vineyard, Massachusetts, generated to calculate shoreline change rates using the Digital Shoreline Analysis System version 5.1: data release product doi:10.5066/P9YGIYFX, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: vector digital data
    Source_Contribution:
    Baseline files for region published as part of the Massachusetts Shoreline Change Project, 2021 Update used for shoreline change analysis with DSAS v5.1
    MarthasVS_baseline (source 3 of 3)
    Bartlett, Marie K., Henderson, Rachel E., Farris, Amy S., and Himmelstoss, Emily A., 2021, Baseline for the southern coast of Martha's Vineyard, Massachusetts, generated to calculate shoreline change rates using the Digital Shoreline Analysis System version 5.1: data release product doi:10.5066/P9YGIYFX, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: vector digital data
    Source_Contribution:
    Baseline files for region published as part of the Massachusetts Shoreline Change Project, 2021 Update used for shoreline change analysis with DSAS v5.1
  2. How were the data generated, processed, and modified?
    Date: 2020 (process 1 of 11)
    Explanation of the methods used to calculate shoreline change rates as part of the 2021 update for the Massachusetts Office of Coastal Zone Management Shoreline Change Project: This data release consists of rate transect files that hold long- and short-term rates of shoreline change. Depending on the available data, the shorelines used for analysis may include those referenced to mean high water (MHW) or a proxy-based high water line (HWL).Transects with both MHW and HWL shorelines will have the proxy-datum bias applied. Shoreline data from the 2021 data release (historical and 2018), were merged into a single feature class (MA_shorelines_LT) for the long-term shoreline change. Form this completed shoreline compilation - shoreline data were extracted for the last 30 years and merged into a feature class (MA_shorelines_ST) to calculate short-term shoreline change. All files were projected to UTM zone 19N coordinates and confirmed to have the same attribute names needed for use in DSAS. Note the range of shoreline dates will vary by location. Please check the corresponding intersect file for a record of the exact dates used. This process step and all subsequent process steps were performed by the same person: Marie K. Bartlett Person who carried out this activity:
    Marie K. Bartlett
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, MA
    USA

    508-548-8700 x2306 (voice)
    mbartlett@usgs.gov
    Data sources used in this process:
    • MA 1844 - 2018 Shorelines
    Data sources produced in this process:
    • MA_shorelines_LT
    • MA_shorelines_ST
    Date: 2021 (process 2 of 11)
    Transect features generated in a personal geodatabase using DSAS v5.1.2020.0720.0030. Parameters Used: baseline layer= MarthasVN_baseline, baseline group field=DSAS_group, transect spacing=50 meters, search distance=200 meters, land direction=left, shoreline intersection=seaward, File produced = MarthasVN_transects_LT. For additional details on these parameters, please see the DSAS help file distributed with the DSAS software, or visit the USGS website at: https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas. Some transects were manually edited for length, moved, or deleted in an edit session using standard editing tools in ArcMap v10.7.1 Data sources used in this process:
    • MA_shorelines_LT
    • MarthasVN_baseline
    Data sources produced in this process:
    • MarthasVN_transects_LT
    Date: 2021 (process 3 of 11)
    Shoreline intersects and rate calculations performed for long-term rates with and without bias. Parameters Used: shoreline layer= MA_shorelines_LT, shoreline date field=Date_, shoreline uncertainty field name=Uncy, the default accuracy=10 meters, shoreline intersection=seaward, stats calculations=[SCE, NSM, LRR], shoreline threshold=3, confidence interval=90%. Files produced = MarthasVN_trans_LT_rates_20210318_133812, MarthasVN_trans_LT_intersect_20210318_133812. NOTE: All shorelines have an uncertainty value listed in the attribute table that provides the horizontal uncertainty associated with the shoreline, regardless of the method used. The shoreline database contains both MHW and HWL shorelines Therefore a proxy-datum bias (PDB), stored as a line feature class appended to the reference baseline, is applied during rate calculation. For more information about the origin of the proxy-datum bias, see Ruggiero and List (2009). Rate statistics are presented with both the PDB applied, and with the bias omitted, in which case the attribute field will show “NB_” or “No bias”. The bias uncertainty values are stored within the bias feature attribute table. Data sources used in this process:
    • MA_shorelines_LT
    • MarthasVN_transects_LT
    Data sources produced in this process:
    • MarthasVN_trans_rates_LT
    • MarthasVN_intersects_LT
    Date: 2021 (process 4 of 11)
    Transect features generated in a personal geodatabase using DSAS v5.1.2020.0720.0030. Parameters Used: baseline layer= MarthasVN_baseline, baseline group field=DSAS_group, transect spacing=50 meters, search distance=200 meters, land direction=left, shoreline intersection=seaward, File produced = MarthasVN_transects_ST. For additional details on these parameters, please see the DSAS help file distributed with the DSAS software, or visit the USGS website at: https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas Some transects were manually edited for length, moved, or deleted in an edit session using standard editing tools in ArcMap v10.7.1 Data sources used in this process:
    • MA_shorelines_ST
    • MarthasVN_baseline
    Data sources produced in this process:
    • MarthasVN_transects_ST
    Date: 2021 (process 5 of 11)
    Shoreline intersects and rate calculations performed for long-term rates with and without bias. Parameters Used: shoreline layer= MA_shorelines_ST, shoreline date field=Date_, shoreline uncertainty field name=Uncy, the default accuracy=5.1 meters, shoreline intersection=seaward, stats calculations=[SCE, NSM, EPR LRR], shoreline threshold=2, confidence interval=90%. Files produced = MarthasVN_trans_ST_rates_20210322_151603, MarthasVN_trans_ST_intersect_20210322_151603. NOTE: All shorelines have an uncertainty value listed in the attribute table that provides the horizontal uncertainty associated with the shoreline, regardless of the method used. The shoreline database contains both MHW and HWL shorelines thus a proxy-datum bias (PDB), stored as a line feature class appended to the reference baseline, is applied during rate calculation. For more information about the origin of the proxy-datum bias, see Ruggiero and List (2009). Rate statistics are presented with both the PDB applied, and with the bias omitted, in which case the attribute field will show “NB_” or “No bias”. The bias uncertainty values are stored within the bias feature attribute table. Data sources used in this process:
    • MA_shorelines_ST
    • MarthasVN_transects_ST
    Data sources produced in this process:
    • MarthasVN_trans_rates_ST
    • MarthasVN_intersects_ST
    Date: 2021 (process 6 of 11)
    Transect features generated in a personal geodatabase using DSAS v5.1.2020.0720.0030. Parameters Used: baseline layer= MarthasVS_baseline, baseline group field=DSAS_group, transect spacing=50 meters, search distance=200 meters, land direction=left, shoreline intersection=seaward, File produced = MarthasVS_transects_LT. For additional details on these parameters, please see the DSAS help file distributed with the DSAS software, or visit the USGS website at: https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas. Some transects were manually edited for length, moved, or deleted in an edit session using standard editing tools in ArcMap v10.7.1 Data sources used in this process:
    • MA_shorelines_LT
    • MarthasVS_baseline
    Data sources produced in this process:
    • MarthasVS_transects_LT
    Date: 2021 (process 7 of 11)
    Shoreline intersects and rate calculations performed for long-term rates with and without bias. Parameters Used: shoreline layer= MA_shorelines_LT, shoreline date field=Date_, shoreline uncertainty field name=Uncy, the default accuracy=10 meters, shoreline intersection=seaward, stats calculations=[SCE, NSM, LRR], shoreline threshold=3, confidence interval=90%. Files produced = MarthasVS_trans_rates_LT_20210702_122450, MarthasVS_trans_LT_intersect_20210702_122450. NOTE: All shorelines have an uncertainty value listed in the attribute table that provides the horizontal uncertainty associated with the shoreline, regardless of the method used. The shoreline database contains both MHW and HWL shorelines Therefore a proxy-datum bias (PDB), stored as a line feature class appended to the reference baseline, is applied during rate calculation. For more information about the origin of the proxy-datum bias, see Ruggiero and List (2009). Rate statistics are presented with both the PDB applied, and with the bias omitted, in which case the attribute field will show “NB_” or “No bias”. The bias uncertainty values are stored within the bias feature attribute table. Data sources used in this process:
    • MA_shorelines_LT
    • MarthasVS_transects_LT
    Data sources produced in this process:
    • MarthasVS_trans_rates_LT
    • MarthasVS_intersects_LT
    Date: 2021 (process 8 of 11)
    Transect features generated in a personal geodatabase using DSAS v5.1.2020.0720.0030. Parameters Used: baseline layer= MarthasVS_baseline, baseline group field=DSAS_group, transect spacing=50 meters, search distance=200 meters, land direction=left, shoreline intersection=seaward, File produced = MarthasVS_transects_ST. For additional details on these parameters, please see the DSAS help file distributed with the DSAS software, or visit the USGS website at: https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas Some transects were manually edited for length, moved, or deleted in an edit session using standard editing tools in ArcMap v10.7.1 Data sources used in this process:
    • MA_shorelines_ST
    • MarthasVS_baseline
    Data sources produced in this process:
    • MarthasVS_transects_ST
    Date: 2021 (process 9 of 11)
    Shoreline intersects and rate calculations performed for long-term rates with and without bias. Parameters Used: shoreline layer= MA_shorelines_ST, shoreline date field=Date_, shoreline uncertainty field name=Uncy, the default accuracy=5.1 meters, shoreline intersection=seaward, stats calculations=[SCE, NSM, EPR LRR], shoreline threshold=2, confidence interval=90%. Files produced = MarthasVS_trans_rates_ST_20210702_124821, MarthasVS_intersect_ST_20210702_124821. NOTE: All shorelines have an uncertainty value listed in the attribute table that provides the horizontal uncertainty associated with the shoreline, regardless of the method used. The shoreline database contains both MHW and HWL shorelines thus a proxy-datum bias (PDB), stored as a line feature class appended to the reference baseline, is applied during rate calculation. For more information about the origin of the proxy-datum bias, see Ruggiero and List (2009). Rate statistics are presented with both the PDB applied, and with the bias omitted, in which case the attribute field will show “NB_” or “No bias”. The bias uncertainty values are stored within the bias feature attribute table. Data sources used in this process:
    • MA_shorelines_ST
    • MarthasVS_transects_ST
    Data sources produced in this process:
    • MarthasVS_trans_rates_ST
    • MarthasVS_intersects_ST
    Date: 2021 (process 10 of 11)
    The rate feature classes were exported to shapefiles in ArcMap v10.7.1 by right-clicking the transect layer > Data > Export data.
    Date: 2021 (process 11 of 11)
    The exported rate shapefiles were projected in Esri's ArcToolbox (v10.7.1) > Data Management Tools > Projections and Transformations > Project. Parameters: input projection = UTM zone 19N (WGS84); output projection = geographic coordinates (WGS84); transformation = none. Data sources used in this process:
    • MarthasVN_trans_rates_LT
    • MarthasVN_trans_rates_ST
    • MarthasVS_trans_rates_LT
    • MarthasVS_trans_rates_ST
    Data sources produced in this process:
    • MarthasVN_rates_LT
    • MarthasVN_rates_ST
    • MarthasVS_rates_LT
    • MarthasVS_rates_ST
  3. What similar or related data should the user be aware of?
    Himmelstoss, E.A., Farris, A.S., Henderson, R.E., Kratzmann, M.G., Ergul, A., Zhang, O., Zichichi, J.L., and Thieler, E.R., 2018, Digital Shoreline Analysis System (version 5): U.S. Geological Survey software: software version 5, U.S. Geological Survey, Coastal and Marine Geology Program, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Himmelstoss, E.A., Farris, A.S., Henderson, R.E., Kratzmann, M.G., Ergul, A., Zhang, O., Zichichi, J.L., and Thieler, E.R., 2018, Digital Shoreline Analysis System (ver. 5.0): U.S. Geological Survey software, https://doi.org/10.5066/P9VW42I0 .
    Himmelstoss, E.A., Henderson, R.E., Kratzmann, M.G., and Farris, A., 2018, Digital Shoreline Analysis System (DSAS) Version 5 User Guide: Open File Report 2018-1179, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole, MA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Himmelstoss, E.A., Henderson, R.E., Kratzmann, M, Farris, A., 2018, DSAS version 5.0 user guide. U.S. Geological Survey report 2018-1179, https://doi.org/10.3133/ofr20181179
    Thieler, E.R., Smith, T.I., Knisel, Julia, and Sampson, D.W., 2013, Massachusetts Shoreline Change Mapping and Analysis Project, 2012 Update: Open-File Report 2012-1189, U.S. Geological Survey, Reston, VA.

    Online Links:

    Himmelstoss, Emily A., Farris, Amy S., and Weber, Kathryn M., 2018, Massachusetts Shoreline Change Project: A GIS Compilation of Vector Shorelines for the 2018 update: Data Release DOI:10.5066/P9O7S72B, U.S. Geological Survey, Reston, VA.

    Online Links:

    Ruggiero, Peter, and List, Jeffrey H., 200909, Improving Accuracy and Statistical Reliability of Shoreline Position and Change Rate Estimates: Journal of Coastal Research vol. 255, Coastal Education and Research Foundation, n/a.

    Online Links:

    Himmelstoss, Emily A., Farris, Amy S., and Weber, Kathryn M., 2019, Massachusetts Shoreline Change Project, 2018 Update: A GIS Compilation of Shoreline Change Rates Calculated Using Digital Shoreline Analysis System Version 5.0, With Supplementary Intersects and Baselines for Massachusetts: Data release DOI:10.5066/P9RRBEYK.

    Online Links:


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?
    The uncertainty of the linear regression rate is estimated by the elements LR2, LSE and LCI90_0. See the attribute definition of each for more information.
  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 shoreline change rates for the region. Additional transects may have been generated but did not intersect the minimum requirement of three shorelines. Shoreline change rates data are provided where there are available shorelines to compute change metrics.
  5. How consistent are the relationships among the observations, including topology?
    These data were generated using DSAS v5.1. The transects automatically generated by the software were visually inspected along with the shoreline data prior to rate calculations. Sometimes transect positions were manually edited within a standard ArcMap edit session to adjust the position at which an individual transect intersected the shorelines to better represent an orthogonal position to the general trend of the coast over time.

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 v5.1 software applications. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset. These data are not to be used for navigation.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - ScienceBase
    Federal Center, Building 810, MS 302
    Denver, CO

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? The dataset contains the rate transect features used to store shoreline change data, (SHP and other shapefile components), browse graphic, and the FGDC CSDGM metadata in XML format.
  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. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), and have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. 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?
  5. What hardware or software do I need in order to use the data set?
    These data are available in a point shapefile format. The user must have software to read and process the data components of a shapefile.

Who wrote the metadata?

Dates:
Last modified: 19-Mar-2024
Metadata author:
U.S. Geological Survey
Attn: Marie Bartlett
Geologist
384 Woods Hole Rd
Woods Hole, MA
USA

508-548-8700 x2306 (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 person is no longer with USGS. (updated on 20240319)
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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