Long and short-term shoreline intersect points for the central coast of North Carolina (NCcentral), calculated using the Digital Shoreline Analysis System version 5.1

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   Bartlett, Marie K., 20231023, Long and short-term shoreline intersect points for the central coast of North Carolina (NCcentral), calculated using the Digital Shoreline Analysis System version 5.1: data release doi:10.5066/P9HYNUNV, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

   Online Links:

   • https://doi.org/10.5066/P9HYNUNV
   • https://www.sciencebase.gov/catalog/item/64dfa90ed34e5f6cd553bc49

   This is part of the following larger work.
   Bartlett, Marie K., Farris, Amy S., Weber, Kathryn M., and Henderson, Rachel E., 2023, USGS National Shoreline Change — 2017 lidar-derived mean high water shoreline and associated shoreline change data for coastal North Carolina: data release doi:10.5066/P9HYNUNV, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.5066/P9HYNUNV
   • https://www.sciencebase.gov/catalog/item/64de3810d34e5f6cd5533c78

   Other_Citation_Details:

   Bartlett, M.K., Farris, A.S., Weber, K.M., and Henderson, R.E., 2023, USGS National Shoreline Change — 2017 lidar-derived mean high water shoreline and associated shoreline change data for coastal North Carolina: U.S. Geological Survey data release, https://doi.org/P9HYNUNV.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -76.555545
   East_Bounding_Coordinate: -75.521382
   North_Bounding_Coordinate: 35.240768
   South_Bounding_Coordinate: 34.582266
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/64dfa90ed34e5f6cd553bc49?name=NCcentral_intersects_browse.PNG (PNG)

   Map view of dataset

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

   Beginning_Date:

   Ending_Date: 2017

   Currentness_Reference:

   ground condition at the time of shoreline source data

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?
      

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:

      UTM_Zone_Number: 18
      Transverse_Mercator:

      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -81.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0
      

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.6096
      Ordinates (y-coordinates) are specified to the nearest 0.6096
      Planar coordinates are specified in meters
      The horizontal datum used is WGS_1984.
      The ellipsoid used is WGS_84.
      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?

   NCcentral_intersects_LT

   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 correction applied. Point Vector Count: 17398 (Source: U.S. Geological Survey (USGS))

   FID

   Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.

   Shape

   Feature geometry. (Source: Esri) Feature geometry. Intersects are point shapefiles.

   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. (Source: USGS)

   Range of values
   Minimum:	2
   Maximum:	4

   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. Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) shoreline movement. (Source: USGS)

   Range of values
   Minimum:	-1164.883
   Maximum:	872.406
   Units:	meters

   IntersectX

   The easting or X-coordinate location of the intersect point in WGS84 UTM17N. (Source: USGS)

   Range of values
   Minimum:	358449.706
   Maximum:	452187.236
   Units:	meters

   IntersectY

   The northing or Y-coordinate location of the intersect point in WGS84 UTM18N. (Source: USGS)

   Range of values
   Minimum:	3827801.774
   Maximum:	3899870.419
   Units:	meters

   Uncertaint

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

   Range of values
   Minimum:	2.45
   Maximum:	10.8
   Units:	meters

   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 correction applied. May be positive or negative depending on the orientation of the baseline. (Source: USGS)

   Range of values
   Minimum:	-1155.875
   Maximum:	872.406
   Units:	meters

   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:	8.598
   Maximum:	12.902
   Units:	meters

   BIAS_X

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

   Range of values
   Minimum:	358458.686
   Maximum:	452184.046
   Units:	meters

   BIAS_Y

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

   Range of values
   Minimum:	3827801.774
   Maximum:	3899862.117
   Units:	meters

   Bias_Uncer

   The uncertainty associated with the shoreline once the bias correction has been applied. It is the quadrature sum of the shoreline uncertainty and the uncertainty of the bias estimate. (Source: USGS)

   Range of values
   Minimum:	2.45
   Maximum:	12.69
   Units:	meters

   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:	1
   Maximum:	2434

   NCcentral_intersects_ST

   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. Because only modern, MHW lidar shorelines were used to calculate short-term rates, the proxy-datum bias calculation does not apply. Point Vector Count: 5210 (Source: U.S. Geological Survey (USGS))

   FID

   Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.

   Shape

   Feature geometry. (Source: Esri) Feature geometry. Intersects are point shapefiles.

   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. (Source: USGS)

   Range of values
   Minimum:	2
   Maximum:	4

   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. Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) shoreline movement. (Source: USGS)

   Range of values
   Minimum:	-816.357
   Maximum:	872.406
   Units:	meters

   IntersectX

   The easting or X-coordinate location of the intersect point in WGS84 UTM18N. (Source: USGS)

   Range of values
   Minimum:	359254.099
   Maximum:	451624.631
   Units:	meters

   IntersectY

   The northing or Y-coordinate location of the intersect point in WGS84 UTM18N. (Source: USGS)

   Range of values
   Minimum:	3827801.774
   Maximum:	3899218.954
   Units:	meters

   Uncertaint

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

   Range of values
   Minimum:	2.446
   Maximum:	5.1
   Units:	meters

   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:	1
   Maximum:	2340

   Entity_and_Attribute_Overview:

   The entity and attribute information provided here describes the tabular data associated with the intersects needed to calculate long-term (up to 169 years) and short-term (up to 20 years) rates of change. Please review the individual attribute descriptions for detailed information. All calculations for length are in meter units and were based on the UTM zone 18N WGS 84 projection (NCnorth, NCcentral, NCwest) or UTM zone 17N (NCwest) projection.

   Entity_and_Attribute_Detail_Citation: U.S. Geological Survey
   

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Marie K. Bartlett
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   Marie K. Bartlett

   U.S. Geological Survey

   Geologist

   384 Woods Hole Rd

   Woods Hole, MA
   

   508-457-8700 x2306 (voice)

   mbartlett@usgs.gov

Why was the data set created?

How was the data set created?

1. From what previous works were the data drawn?
2. How were the data generated, processed, and modified?

   Date: 2023 (process 1 of 3)

   Step 1: Long-term (LT) rate calculations were performed producing rates and intersect points with and without the proxy-datum bias correction.
   DSAS parameters used: Shoreline layer = NCcentral_shorelines, Shoreline date field = Date_, shoreline uncertainty field name = Uncy, default accuracy = 5.1 meters, shoreline intersection = seaward, stats calculations = [LRR], shoreline threshold = 3, confidence interval=90%. Files produced = NCcentral_rates_LT, NCcentral_intersects_LT. The historical shoreline database contains both MHW and HWL shorelines thus a proxy-datum bias (PDB), stored as a line feature class is appended to the reference baseline. The PDB is applied during rate calculation. For more information about the origin of the PDB see Ruggiero and List (2009), which is cross-referenced in this metadata file. Rate statistics are presented with and without the PDB correction applied, denoted in the long-term rates attribute table (see larger work citation, NCcentral_rates_LT) with a prefix of “NB_” or “No bias”. The bias uncertainty values are stored within the bias feature attribute table (see larger work citation, NCcentral_bias_feature). Person who carried out this activity:
   

   Marie K. Bartlett

   U.S. Geological Survey

   Geologist

   384 Woods Hole Road

   Woods Hole, MA
   

   508-548-8700 x 2306 (voice)

   mbartlett@usgs.gov

   Data sources used in this process:

   • NCcentral_trans_LT
   • NCcentral_bias_feature
   • NCcentral_shorelines

   Data sources produced in this process:

   • NCcentral_rates_LT
   • NCcentral_intersects_LT

   Date: 2023 (process 2 of 3)

   Step 2: Short-term (ST) rate calculations were performed without a proxy-datum bias correction which was unnecessary, since only datum-based MHW shorelines (1997-2017) were used.
   DSAS parameters used: shoreline layer = NCcentral_shorelines_ST, shoreline date field = Date_, shoreline uncertainty field name = Uncy, default accuracy = 5.1 meters, shoreline intersection = seaward, stats calculations = [LRR], shoreline threshold = 2, confidence interval=90%. Files produced = NCcentral_rates_ST, NCcentral_intersects_ST. Data sources used in this process:

   • NCcentral_trans_ST
   • NCcentral_bias_feature
   • NCcentral_shorelines_ST

   Data sources produced in this process:

   • NCcentral_rates_ST
   • NCcentral_intersects_ST

   Date: 2023 (process 3 of 3)

   The long-term and short-term intersect feature classes were exported to shapefiles in ArcMap v10.7.1 by right-clicking the transect layer > data > export data. Coordinate system: UTM Zone 18N.

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, Zichichi, Jessica L., and Thieler, E. Robert, 2021, Digital Shoreline Analysis System (version 5.1): U.S. Geological Survey Software: software release version 5.1, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://code.usgs.gov/cch/dsas/
   • https://doi.org/10.5066/P9VW42I0
   • https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas

   Other_Citation_Details:

   Use the first two links to access the software. The third link directs to the DSAS project page. Current version of software at time of use was 5.1.

   Himmelstoss, Emily A., Henderson, Rachel E., Kratzmann, Meredith G., and Farris, Amy S., 20211019, Digital Shoreline Analysis System (version 5.1) User Guide: Open-File Report 2021-1091, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.3133/ofr20211091
   • https://www.usgs.gov/centers/whcmsc/science/digital-shoreline-analysis-system-dsas

   Other_Citation_Details:

   Refer to the DSAS user guide for more information about attribute requirements, accuracy reports, and feature creation.

   Himmelstoss, Emily A., Kratzmann, Meredith G., and Thieler, E. Robert, 2017, National assessment of shoreline change—Summary statistics for updated vector shorelines and associated shoreline change data for the Gulf of Mexico and Southeast Atlantic coasts: Open-File Report 2017-1015, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.3133/ofr20171015

   Kratzmann, Meredith G., Himmelstoss, Emily A., and Thieler, E. Robert, 2017, National assessment of shoreline change – A GIS compilation of updated vector shorelines and associated shoreline change data for the Southeast Atlantic Coast: data release 2017, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.5066/F74X55X7
   • https://www.sciencebase.gov/catalog/item/58055f50e4b0824b2d1c1ee7

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 while creating the intersects layer or during the calculation of shoreline change rates.
2. How accurate are the geographic locations?
   The intersection points represent the location where transects cast by the DSAS software crosses a historical shoreline position. The positional uncertainties associated with the shoreline and intersection points are captured in the shoreline attribute table (see larger work citation, and NCcentral_shoreline_2017). See Kratzmann and others (2017) for uncertainties associated with historical (1848-2010) shoreline positions.
3. How accurate are the heights or depths?
   
4. Where are the gaps in the data? What is missing?
   This dataset contains the intersects automatically generated by the DSAS software application that were used to calculate shoreline change rates for the region.
5. How consistent are the relationships among the observations, including topology?
   These data were generated using DSAS v5.1, 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, such as those crossing man-made coastal structures, were included in the desired long-term (LT) or short-term (ST) shoreline change analysis. It is possible that a centimeter-scale offset may occur when projecting from outside of the spatial reference system used for analysis (UTM Zone 18N WGS84 or UTM Zone 17N WGS84). This is an artifact of the projection process; rate data are unaffected.

How can someone get a copy of the data set?

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

   Attn: USGS 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 data representing the intersection of North Carolina shorelines and transect data (NCcentral_intersects_LT.shp, NCcentral_intersects_ST.shp and other shapefile components), browse graphic (NCcentral_intersects_browse.PNG), 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. 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, 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. Additional files of the same name included are FGDC CSDGM-compliant metadata in XML format. in format Shapefile (version ArcGIS 10.7.1) Esri Point Shapefile Size: 1.2
     Network links:	https://doi.org/10.5066/P9HYNUNV https://www.sciencebase.gov/catalog/file/get/64dfa90ed34e5f6cd553bc49 https://www.sciencebase.gov/catalog/item/64dfa90ed34e5f6cd553bc49

   • Cost to order the data: None.

Who wrote the metadata?

Dates:

Last modified: 23-Oct-2023

Metadata author:

Marie K. Bartlett

U.S. Geological Survey

384 Woods Hole Rd

Woods Hole, MA

USA

508-548-8700 x2306 (voice)

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.

Metadata standard:

FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)