Intersects for coastal region of Nantucket, Massachusetts, generated to calculate shoreline change rates using the Digital Shoreline Analysis System version 5.1

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What does this data set describe?

1. How might this data set be cited?
   U.S. Geological Survey, 20210831, Intersects for coastal region of Nantucket, Massachusetts, generated to calculate shoreline change rates 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:

   • https://doi.org/10.5066/P9YGIYFX
   • https://www.sciencebase.gov/catalog/item/6108308dd34ef8d70565bd53

   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:

   • https://www.sciencebase.gov/catalog/item/60ff22dad34e3ccd830d62aa
   • https://doi.org/10.5066/P9YGIYFX

   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: -70.3193
   East_Bounding_Coordinate: -69.9592
   North_Bounding_Coordinate: 41.3873
   South_Bounding_Coordinate: 41.2374
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/6108308dd34ef8d70565bd53?name=Nantucket_intersects_browse.PNG (png)

   Map view of data

4. Does the data set describe conditions during a particular time period?

   Calendar_Date: 2021

   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
   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 0.0197425946. Longitudes are given to the nearest 0.0261674174. Latitude and longitude values are specified in Decimal seconds. The horizontal datum used is WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.
      
7. How does the data set describe geographic features?

   NantucketN_intersects_LT.shp

   The intersection points are generated by DSAS where each DSAS generated transect crosses a shoreline. These intersections represent the shoreline position, and contain the data necessary for DSAS to compute long-term rates, with and without the proxy-datum bias. Point Object Count: 8624 (Source: USGS)

   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

   The geometry field (shape) is automatically created and maintained by ArcGIS. It provides a definition of the feature type (point, line, polygon). (Source: ESRI) Coordinates defining the features.

   TransectID

   The TransectID relates directly to the original transect file Object Identifier, ObjectID or OID (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

   BaselineID

   Values in this field correlate to the baseline attribute field ID and are assigned by DSAS to identify the baseline segment used to generate the measurement transect. Baseline segments assigned an ID = 0 are ignored by DSAS and no transects will be cast along those line segments. (Source: USGS)

   Range of values
   Minimum:	1
   Maximum:	unlimited

   ShorelineI

   Date of shoreline position; date of survey as determined from shoreline layer. (Source: USGS) Date of the shoreline in mm/dd/yyyy

   Distance

   The distance in meters between the DSAS reference baseline and the shoreline intersection point along a DSAS transect. (Source: USGS) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin.

   IntersectX

   The X-coordinate location in eastings of the intersect point in WGS84 UTM19N. (Source: USGS)

   Range of values
   Minimum:	389613.315173
   Maximum:	416575.523026

   IntersectY

   The Y-coordinate location in northings of the intersect point in WGS84 UTM19N. (Source: USGS)

   Range of values
   Minimum:	4569871.586360
   Maximum:	4582287.530220

   Uncertaint

   The uncertainty of the shoreline intersect point as defined by the positional-uncertainty value (DSAS_uncy) of the shoreline (ShorelineID). (Source: USGS)

   Range of values
   Minimum:	0
   Maximum:	unlimited

   Bias_Dista

   The distance in meters between the DSAS reference baseline and the shoreline intersection point along a DSAS transect with the proxy-datum bias applied. May be positive or negative depending on the orientation of the baseline. (Source: USGS)

   Range of values
   Minimum:	-366.767791
   Maximum:	770.797716

   BIAS

   The estimated unidirectional horizontal offset between the MHW elevation of the lidar data and the HWL shoreline position. (Source: USGS)

   Range of values
   Minimum:	0
   Maximum:	unlimited

   BIAS_X

   The X-coordinate location of the intersect point with the bias applied. (Source: USGS)

   Range of values
   Minimum:	389613.314204
   Maximum:	416575.522026

   BIAS_Y

   The Y-coordinate location of the intersect point with the bias applied. (Source: USGS)

   Range of values
   Minimum:	4569871.587320
   Maximum:	4582287.529650

   Bias_Uncer

   This is an estimate of the uncertainty of the bias corrected shoreline. It is the shoreline uncertainty and the bias uncertainty added in quadrature (Source: USGS)

   Range of values
   Minimum:	0
   Maximum:	unlimited

   NantucketN_intersects_ST.shp

   The intersection points are generated by DSAS where each DSAS generated transect crosses a shoreline. These intersections represent the shoreline position, and contain the data necessary for DSAS to compute short-term rates, with and without the proxy-datum bias. Point Object Count: 5253 (Source: USGS)

   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

   The geometry field (shape) is automatically created and maintained by ArcGIS. It provides a definition of the feature type (point, line, polygon). (Source: ESRI) Coordinates defining the features.

   TransectID

   The TransectID relates directly to the original transect file Object Identifier, ObjectID or OID (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

   BaselineID

   Values in this field correlate to the baseline attribute field ID and are assigned by DSAS to identify the baseline segment used to generate the measurement transect. Baseline segments assigned an ID = 0 are ignored by DSAS and no transects will be cast along those line segments. (Source: USGS)

   Range of values
   Minimum:	1
   Maximum:	unlimited

   ShorelineI

   Date of shoreline position; date of survey as determined from shoreline layer. (Source: USGS) Date of the shoreline in mm/dd/yyyy

   Distance

   The distance in meters between the DSAS reference baseline and the shoreline intersection point along a DSAS transect. (Source: USGS) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin.

   IntersectX

   The X-coordinate location in eastings of the intersect point in WGS84 UTM19N. (Source: USGS)

   Range of values
   Minimum:	390324.256875
   Maximum:	416455.995027

   IntersectY

   The Y-coordinate location in northings of the intersect point in WGS84 UTM19N. (Source: USGS)

   Range of values
   Minimum:	4569927.717940
   Maximum:	4582770.774950

   Uncertaint

   The uncertainty of the shoreline intersect point as defined by the positional-uncertainty value (DSAS_uncy) of the shoreline (ShorelineID). (Source: USGS)

   Range of values
   Minimum:	0
   Maximum:	unlimited

   Bias_Dista

   The distance in meters between the DSAS reference baseline and the shoreline intersection point along a DSAS transect with the proxy-datum bias applied. May be positive or negative depending on the orientation of the baseline. (Source: USGS)

   Range of values
   Minimum:	-241.937383
   Maximum:	500.466767

   BIAS

   The estimated unidirectional horizontal offset between the MHW elevation of the lidar data and the HWL shoreline position. (Source: USGS)

   Range of values
   Minimum:	0
   Maximum:	unlimited

   BIAS_X

   The X-coordinate location of the intersect point with the bias applied. (Source: USGS)

   Range of values
   Minimum:	390324.256036
   Maximum:	416455.994028

   BIAS_Y

   The Y-coordinate location of the intersect point with the bias applied. (Source: USGS)

   Range of values
   Minimum:	4569927.718920
   Maximum:	4582770.774860

   Bias_Uncer

   This is an estimate of the uncertainty of the bias corrected shoreline. It is the shoreline uncertainty and the bias uncertainty added in quadrature. (Source: USGS)

   Range of values
   Minimum:	0
   Maximum:	unlimited

   NantucketS_intersects_LT.shp

   The intersection points are generated by DSAS where each DSAS generated transect crosses a shoreline. These intersections represent the shoreline position, and contain the data necessary for DSAS to compute long-term rates, with and without the proxy-datum bias. Point Object Count: 8900 (Source: USGS)

   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

   The geometry field (shape) is automatically created and maintained by ArcGIS. It provides a definition of the feature type (point, line, polygon). (Source: ESRI) Coordinates defining the features.

   TransectID

   The TransectID relates directly to the original transect file Object Identifier, ObjectID or OID (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

   BaselineID

   Values in this field correlate to the baseline attribute field ID and are assigned by DSAS to identify the baseline segment used to generate the measurement transect. Baseline segments assigned an ID = 0 are ignored by DSAS and no transects will be cast along those line segments. (Source: USGS)

   Range of values
   Minimum:	1
   Maximum:	unlimited

   ShorelineI

   Date of shoreline position; date of survey as determined from shoreline layer. (Source: USGS) Date of the shoreline in mm/dd/yyyy

   Distance

   The distance in meters between the DSAS reference baseline and the shoreline intersection point along a DSAS transect. (Source: USGS) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin.

   IntersectX

   The X-coordinate location in eastings of the intersect point in WGS84 UTM19N. (Source: USGS)

   Range of values
   Minimum:	391927.323340
   Maximum:	419661.564240

   IntersectY

   The Y-coordinate location in northings of the intersect point in WGS84 UTM19N. (Source: USGS)

   Range of values
   Minimum:	4565606.338520
   Maximum:	4582993.106180

   Uncertaint

   The uncertainty of the shoreline intersect point as defined by the positional-uncertainty value (DSAS_uncy) of the shoreline (ShorelineID). (Source: USGS)

   Range of values
   Minimum:	0
   Maximum:	unlimited

   Bias_Dista

   The distance in meters between the DSAS reference baseline and the shoreline intersection point along a DSAS transect with the proxy-datum bias applied. May be positive or negative depending on the orientation of the baseline. (Source: USGS)

   Range of values
   Minimum:	-867.183515
   Maximum:	598.233840

   BIAS

   The estimated unidirectional horizontal offset between the MHW elevation of the lidar data and the HWL shoreline position. (Source: USGS)

   Range of values
   Minimum:	0
   Maximum:	unlimited

   BIAS_X

   The X-coordinate location of the intersect point with the bias applied. (Source: USGS)

   Range of values
   Minimum:	391919.795010
   Maximum:	419671.276716

   BIAS_Y

   The Y-coordinate location of the intersect point with the bias applied. (Source: USGS)

   Range of values
   Minimum:	4565596.959460
   Maximum:	4583001.208540

   Bias_Uncer

   This is an estimate of the uncertainty of the bias corrected shoreline. It is the shoreline uncertainty and the bias uncertainty added in quadrature (Source: USGS)

   Range of values
   Minimum:	0
   Maximum:	unlimited

   NantucketS_intersects_ST.shp

   The intersection points are generated by DSAS where each DSAS generated transect crosses a shoreline. These intersections represent the shoreline position, and contain the data necessary for DSAS to compute short-term rates, with and without the proxy-datum bias. Point Object Count: 6334 (Source: USGS)

   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

   The geometry field (shape) is automatically created and maintained by ArcGIS. It provides a definition of the feature type (point, line, polygon). (Source: ESRI) Coordinates defining the features.

   TransectID

   The TransectID relates directly to the original transect file Object Identifier, ObjectID or OID (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

   BaselineID

   Values in this field correlate to the baseline attribute field ID and are assigned by DSAS to identify the baseline segment used to generate the measurement transect. Baseline segments assigned an ID = 0 are ignored by DSAS and no transects will be cast along those line segments. (Source: USGS)

   Range of values
   Minimum:	1
   Maximum:	unlimited

   ShorelineI

   Date of shoreline position; date of survey as determined from shoreline layer. (Source: USGS) Date of the shoreline in mm/dd/yyyy

   Distance

   The distance in meters between the DSAS reference baseline and the shoreline intersection point along a DSAS transect. (Source: USGS) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) direction from baseline origin.

   IntersectX

   The X-coordinate location in eastings of the intersect point in WGS84 UTM19N. (Source: USGS)

   Range of values
   Minimum:	392834.500186
   Maximum:	419625.864793

   IntersectY

   The Y-coordinate location in northings of the intersect point in WGS84 UTM19N. (Source: USGS)

   Range of values
   Minimum:	4565729.042400
   Maximum:	4582886.785340

   Uncertaint

   The uncertainty of the shoreline intersect point as defined by the positional-uncertainty value (DSAS_uncy) of the shoreline (ShorelineID). (Source: USGS)

   Range of values
   Minimum:	0
   Maximum:	unlimited

   Bias_Dista

   The distance in meters between the DSAS reference baseline and the shoreline intersection point along a DSAS transect with the proxy-datum bias applied. May be positive or negative depending on the orientation of the baseline. (Source: USGS)

   Range of values
   Minimum:	-876.788089
   Maximum:	100.433676

   BIAS

   The estimated unidirectional horizontal offset between the MHW elevation of the lidar data and the HWL shoreline position. (Source: USGS)

   Range of values
   Minimum:	0
   Maximum:	unlimited

   BIAS_X

   The X-coordinate location of the intersect point with the bias applied. (Source: USGS)

   Range of values
   Minimum:	392826.971857
   Maximum:	419635.588273

   BIAS_Y

   The Y-coordinate location of the intersect point with the bias applied. (Source: USGS)

   Range of values
   Minimum:	4565719.648470
   Maximum:	4582894.887690

   Bias_Uncer

   This is an estimate of the uncertainty of the bias corrected shoreline. It is the shoreline uncertainty and the bias uncertainty added in quadrature (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 the intersects needed to calculate long-term (greater than 50 years, and typically closer to 100 years) and short-term (approximately 30 years) shoreline change rates. 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 intersects, long-term and short-term.

   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?
   U.S. Geological Survey

   Attn: Marie K. Bartlett

   384 Woods Hole Road

   Woods Hole, MA
   

   USA

   508-548-8700 x 2306 (voice)

   508-457-2310 (FAX)

   mbartlett@usgs.gov

Why was the data set created?

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:

   • https://doi.org/10.5066/P9O8QA8N

   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

   NantucketN_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 Nantucket, 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:

   • https://doi.org/10.5066/P9YGIYFX

   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

   NantucketS_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 Nantucket, 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:

   • https://doi.org/10.5066/P9YGIYFX

   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 intersect point shapefiles that hold the data necessary to calculate 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. For 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 intersect file attributes 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: 2020 (process 2 of 11)

   Transect features generated in a personal geodatabase using DSAS v5.1.2020.0720.0030. Parameters Used: baseline layer= NantucketN_baseline, baseline group field=DSAS_group, transect spacing=50 meters, search distance=200 meters, land direction=right, shoreline intersection=seaward, File produced = NantucketN_trans_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
   • NantucketN_baseline

   Data sources produced in this process:

   • NantucketN_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 = NantucketN_trans_LT_rates_20210621_153805, NantucketN_trans_LT_intersect_20210621_153805. 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
   • NantucketN_transects_LT

   Data sources produced in this process:

   • NantucketN_trans_rates_LT
   • NantucketN_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= NantucketN_baseline, baseline group field=DSAS_group, transect spacing=50 meters, search distance=200 meters, land direction=right, shoreline intersection=seaward, File produced = NantucketN_trans_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
   • NantucketN_baseline

   Data sources produced in this process:

   • NantucketN_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 = NantucketN_trans_ST_rates_20210621_163023, NantucketN_trans_ST_intersect_20210621_163023. 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
   • NantucketN_transects_ST

   Data sources produced in this process:

   • NantucketN_trans_rates_ST
   • NantucketN_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= NantucketS_baseline, baseline group field=DSAS_group, transect spacing=50 meters, search distance=200 meters, land direction=left, shoreline intersection=seaward, File produced = NantucketS_trans_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_ST
   • NantucketS_baseline

   Data sources produced in this process:

   • NantucketS_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 = NantucketS_trans_LT_rates_20210706_144229, NantucketS_LT_intersect_20210706_144229. 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_LT
   • NantucketS_transects_LT

   Data sources produced in this process:

   • NantucketS_trans_rates_LT
   • NantucketS_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= NantucketS_baseline, baseline group field=DSAS_group, transect spacing=50 meters, search distance=200 meters, land direction=left, shoreline intersection=seaward, File produced = NantucketS_trans_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
   • NantucketS_baseline

   Data sources produced in this process:

   • NantucketS_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 = NantucketS_trans_ST_rates_20210308_121152, NantucketS_trans_ST_intersect_20210308_121152. 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
   • NantucketS_transects_ST

   Data sources produced in this process:

   • NantucketS_trans_rates_ST
   • NantucketS_intersects_ST

   Date: 2021 (process 10 of 11)

   The intersect 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 intersect 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:

   • NantucketN_intersects_LT
   • NantucketN_intersects_ST
   • NantucketS_intersects_LT
   • NantucketS_intersects_ST

   Data sources produced in this process:

   • NantucketN_intersects_LT
   • NantucketN_intersects_ST
   • NantucketS_intersects_LT
   • NantucketS_intersects_ST

3. What similar or related data should the user be aware of?
   Himmelstoss, Emily A., Farris, Amy S., Henderson, Rachel E., Kratzmann, Meredith G., Ergul, Ayhan, Zhang, Ouya, and Zichichi, Jessica L., 2018, Digital Shoreline Analysis System (version 5.0): U.S. Geological Survey Software: software release version 5.0, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://code.usgs.gov/cch/dsas/
   • https://doi.org/10.5066/P9VW42I0
   • https://woodshole.er.usgs.gov/project-pages/DSAS/

   Himmelstoss, Emily A., Henderson, Rachel E., Kratzmann, Meredith G., and Farris, Amy S., 2018, DSAS v5.0 user guide: Open-File Report 2018-1179, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.3133/ofr20181179
   • https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas

   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

   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, Coastal and Marine Geology Program, Reston, VA.

   Online Links:

   • https://doi.org/10.5066/P9O7S72B
   • https://www.sciencebase.gov/catalog/item/5bcde5dce4b0f0758fc178d0
   • https://www.sciencebase.gov/catalog/file/get/5bcde5dce4b0f0758fc178d0

   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:

   • https://doi.org/10.2112/08-1051.1

   Other_Citation_Details: ppg. 1069-1081
   

   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, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.5066/P9RRBEYK
   • https://www.sciencebase.gov/catalog/item/5be5857ce4b0b3fc5cf8c6ca

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 intersects layer.
2. How accurate are the geographic locations?
   The intersection points represent the location where transects cast by the Digital Shoreline Analysis System (DSAS) software crosses a historical shoreline position. They can be used to visually display which shorelines were used in the rate calculations and capture details on the shoreline represented by the intersection. The distances between the reference baseline and each shoreline intersection along a transect are used by the DSAS software to compute the shoreline change metrics. The positional uncertainties associated with the shoreline and intersection points are captured in the shoreline attribute table.
3. How accurate are the heights or depths?
   
4. Where are the gaps in the data? What is missing?
   This dataset contains all the shoreline/transect intersects used to compute rates in the DSAS v5.1 software application.
5. How consistent are the relationships among the observations, including topology?
   These data were generated using DSAS, an automated software program, which does not perform checks for fidelity of the input features. Following generation of the rates and intersects by the DSAS software a visual inspection of the intersects was performed in map view to determine that no unwanted measurements were included in the desired (long- or short-term) shoreline change analysis.

How can someone get a copy of the data set?

1. Who distributes the data set? (Distributor 1 of 1)
   
   U.S. Geological Survey - GS ScienceBase

   Denver Federal Center, Building 810, Mail Stop 302

   Denver, CO
   

   United States

   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 point intersections used for the analysis of shoreline 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?
   • Availability in digital form:

     Data format:	These files (.cpg, .dbf, .prj, .sbn, .sbx, .shp, .shp., and .shx) are a collection of files with a common filename prefix and must be downloaded and stored in the same directory. Together they are the components of the shapefile and include FGDC CSDGM-compliant metadata. in format Shapefile (version ArcGIS 10.7.1) Esri point shapefile Size: 1
     Network links:	https://www.sciencebase.gov/catalog/file/get/6108308dd34ef8d70565bd53 https://www.sciencebase.gov/catalog/item/6108308dd34ef8d70565bd53 https://doi.org/10.5066/P9YGIYFX

   • Cost to order the data: None

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:

Marie K. Bartlett

U.S. Geological Survey

384 Woods Hole Road

Woods Hole, MA

USA

508-548-8700 x2306 (voice)

508-547-2310 (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 Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)