Intersects for the Northern California coastal region generated to calculate shoreline change rates using the Digital Shoreline Analysis System version 5.0

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Frequently anticipated questions:

What does this data set describe?

Title:
Intersects for the Northern California coastal region generated to calculate shoreline change rates using the Digital Shoreline Analysis System version 5.0
Abstract:
Sandy ocean beaches are a popular recreational destination, often surrounded by communities containing valuable real estate. Development is on the rise despite the fact that coastal infrastructure is subjected to flooding and erosion. As a result, there is an increased demand for accurate information regarding past and present shoreline changes. To meet these national needs, the Coastal and Marine Geology Program of the U.S. Geological Survey (USGS) is compiling existing reliable historical shoreline data along open-ocean sandy shores of the conterminous United States and parts of Alaska and Hawaii as part of the Coastal Change Hazards programmatic focus, formerly the National Assessment of Shoreline Change project.
There is no widely accepted standard for analyzing shoreline change. Existing shoreline data measurements and rate calculation methods vary from study to study and prevent combining results into state-wide or regional assessments. The impetus behind this national scale project was to develop a standardized method of measuring changes in shoreline position that is consistent from coast to coast. The goal was to facilitate the process of periodically and systematically updating the results in an internally consistent manner.
In this release, three new tidal datum-based mean high water (MHW) shorelines extracted from 2009/2010/2011, 2015, and 2016 lidar elevation data are included in the analysis (coverage not necessarily continuous statewide). The full range of shoreline data is 1852 to 2016. The proxy-datum bias correction has been applied on a transect-by-transect basis to reconcile offsets between the MHW shorelines and proxy-based HWL shorelines for the entire California coastal region which is divided into three subregions: Northern California (NorCal), Central California (CenCal), and Southern California (SoCal). In the previous report (Hapke et al., 2006), the proxy-datum bias correction was only applied to regional shoreline averages.
This shoreline change update for California reports proxy-datum bias corrected rates when that information was computed while extracting shoreline positions from lidar data. In areas where the methods for delineating shorelines did not include computing bias correction values, the rates are reported without that correction. The proxy-datum bias concept is explained further in Ruggiero and List (2009) and in the process steps of the metadata file associated with the transect rates.
  1. How might this data set be cited?
    U.S. Geological Survey, 20240112, Intersects for the Northern California coastal region generated to calculate shoreline change rates using the Digital Shoreline Analysis System version 5.0: data release DOI:10.5066/P94J0K7Z, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Kratzmann, Meredith G., Farris, Amy S., and Himmelstoss, Emily A., 2024, National Shoreline Change—A GIS compilation of vector shorelines and associated shoreline change data from the 1800s to 2010s for the coast of California: data release DOI:10.5066/P94J0K7Z, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    suggested citation: Kratzmann, M.G., Farris, A.S., and Himmelstoss, E.A., 2024, National Shoreline Change—A GIS compilation of vector shorelines and associated shoreline change data from the 1800s to 2010s for the coast of California: U.S. Geological Survey data release, https://doi.org/10.5066/P94J0K7Z.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -124.407961
    East_Bounding_Coordinate: -122.966502
    North_Bounding_Coordinate: 41.998239
    South_Bounding_Coordinate: 38.230301
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/64add904d34e70357a29326e?name=BG_Norcal_intersects_LT.jpg&allowOpen=true (JPEG)
    Map view of data
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2024
    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 (31818)
    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 0.0000001. Longitudes are given to the nearest 0.0000001. Latitude and longitude values are specified in Decimal degrees. 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?
    Norcal_intersects_LT.shp
    The intersection points are generated by DSAS where each DSAS generated transect crosses a shoreline. These intersections represent the shorelines used to compute long-term shoreline change rates in Northern California (Norcal). (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
    The TransectID relates directly to the original transect file Object Identifier, ObjectID or OID (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:unlimited
    TransOrder
    Assigned by DSAS based on ordering of transects along the baseline. Used 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
    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: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:unlimited
    ShorelineI
    Date of shoreline position; date of survey as determined from shoreline layer. (Source: U.S. Geological Survey) 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: U.S. Geological Survey) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) movement through time.
    IntersectX
    The X-coordinate location in eastings of the intersect point in WGS84 UTM 10N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:380597
    Maximum:502931
    IntersectY
    The Y-coordinate location in northings of the intersect point in WGS84 UTM 10N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:4231368
    Maximum:4650290
    Uncertaint
    The uncertainty of the shoreline position at the intersect point, as defined by the positional uncertainty attribute value (Uncy) of the shoreline. (Source: U.S. Geological Survey)
    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 correction applied.
    A Bias_Dista value of 9999 in the attribute table means that value is Null. ArcGIS automatically changes Null values to zero values when a feature class is exported from a geodatabase to a shapefile. Zero values were changed to 9999 to clearly identify Null values. (Source: U.S. Geological Survey) Decimal values may be positive or negative, which is used to indicate landward (negative) or seaward (positive) movement through time.
    BIAS
    The estimated unidirectional horizontal offset between MHW and HWL shoreline positions based on lidar data.
    A BIAS value of 9999 in the attribute table means that value is Null. ArcGIS automatically changes Null values to zero values when a feature class is exported from a geodatabase to a shapefile. Zero values were changed to 9999 to clearly identify Null values. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:unlimited
    BIAS_X
    The X-coordinate location in eastings of the intersect point with the bias correction applied in WGS84 UTM 10N with the exception of zero values where bias correction was not applied.
    A BIAS_X value of 9999 in the attribute table means that value is Null. ArcGIS automatically changes Null values to zero values when a feature class is exported from a geodatabase to a shapefile. Zero values were changed to 9999 to clearly identify Null values. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:502906
    BIAS_Y
    The Y-coordinate location in northings of the intersect point with the bias correction applied in WGS84 UTM 10N with the exception of zero values where bias correction was not applied.
    A BIAS_Y value of 9999 in the attribute table means that value is Null. ArcGIS automatically changes Null values to zero values when a feature class is exported from a geodatabase to a shapefile. Zero values were changed to 9999 to clearly identify Null values. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:4650287
    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.
    A Bias_Uncer value of 9999 in the attribute table means that value is Null. ArcGIS automatically changes Null values to zero values when a feature class is exported from a geodatabase to a shapefile. Zero values were changed to 9999 to clearly identify Null values. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:unlimited
    Bias_NB
    Describes whether or not the proxy-datum bias correction was applied at a given transect. There may be sections of coast with alternate combinations of shoreline type where the bias correction cannot be applied. For example, transects with only HWL shoreline intersections, or transects that include MHW shoreline intersections with no bias, will not have a bias correction applied. In DSAS v5.0, the bias correction is applied up to 2 kilometers beyond the last bias data point in the baseline flow direction. (Source: U.S. Geological Survey)
    ValueDefinition
    BiasThe proxy-datum bias correction was applied.
    NBThe proxy-datum bias correction was not applied.
    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 greater than 100 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 10N WGS 84 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)
    • 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: Meredith G. Kratzmann
    384 Woods Hole Road
    Woods Hole, MA
    USA

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

Why was the data set created?

This dataset consists of point data which are created by the Digital Shoreline Analysis System (DSAS) version v5.0 at the intersection of shoreline and transect locations. A reference baseline was used as the originating point for the orthogonal transects cast by the DSAS software. These point data contain identification information related to the DSAS transect (TransectID, TransOrder) as well as the shoreline (ShorelineID, Uncertainty). 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?
  2. How were the data generated, processed, and modified?
    Date: 2020 (process 1 of 3)
    Long-term (LT) rate calculations performed for Northern California (Norcal), Central California (Cencal), and Southern California (Socal). For calculation parameters, please see the transects_rates metadata files.
    Rate files produced: (Norcal)= transects_Nor_LT_rates_20200728_170343 (Cencal)= transects_Cen_LT_rates_20200725_175846 (Socal)= transects_So_LT_rates_20200729_163635
    Intersect files produced: (Norcal)= transects_Nor_LT_intersect_20200728_170343 (Cencal)= transects_Cen_LT_intersect_20200725_175846 (Socal)= transects_So_LT_intersect_20200729_163635
    For additional information, 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
    This process step and all subsequent process steps were performed by the same person - Meredith G. Kratzmann. Person who carried out this activity:
    Meredith G. Kratzmann
    U.S. Geological Survey
    384 Woods Hole Road
    Woods Hole, MA
    USA

    508-548-8700 (voice)
    508-457-2310 (FAX)
    mkratzmann@contractor.usgs.gov
    Date: 2020 (process 2 of 3)
    The intersect feature classes were exported to shapefiles in ArcMap v10.7 by right-clicking the transect layer > data > export data. Files renamed [Norcal, Cencal, Socal]_intersects_LT.
    Date: 2020 (process 3 of 3)
    The exported intersect shapefiles were projected in Esri's ArcToolbox (v10.7) > Data Management Tools > Projections and Transformations > Project. Parameters: input projection - UTM zone 10N (WGS84)(Norcal, Cencal), UTM zone 11N (WGS84)(Socal); output projection - geographic coordinates (WGS84); transformation = none.
  3. What similar or related data should the user be aware of?
    Kratzmann, Meredith G., 2024, National Shoreline Change—Summary Statistics of Shoreline Change From the 1800s To the 2010s for the Coast of California: data report 1187, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details: Data report associated with data release DOI:10.5066/P94J0K7Z.
    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:

    Himmelstoss, Emily A., Henderson, Rachel E., Kratzmann, Meredith G., and Farris, Amy S., 2018, Digital Shoreline Analysis System (DSAS) Version 5.0 User Guide: Open-File Report 2018-1179, U.S. Geological Survey, Reston, VA.

    Online Links:

    Hapke, Cheryl J., Reid, David, Richmond, Bruce M., Ruggiero, Peter, and List, Jeff, 2006, National Assessment of Shoreline Change Part 3: Historical Shoreline Change and Associated Coastal Land Loss Along Sandy Shorelines of the California Coast: Open-File Report 2006-1219, 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:

    Other_Citation_Details: pp. 1069-1081

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.
  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 v5.0 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 shoreline change analysis.

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 v5.0 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 - 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.
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (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. Although these data have been processed successfully on a computer system at the U.S. Geological Survey (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.
  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: 12-Jan-2024
Metadata author:
Meredith G. Kratzmann
U.S. Geological Survey
384 Woods Hole Road
Woods Hole, MA
USA

508-548-8700 (voice)
508-457-2310 (FAX)
whsc_data_contact@usgs.gov
Contact_Instructions:
The metadata contact email address is a generic address in the event the person is no longer with USGS.
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P94J0K7Z/Norcal_intersects_LT_metadata.faq.html>
Generated by mp version 2.9.51 on Tue Oct 15 09:53:07 2024