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Computer Software for Calculating Shoreline Change (or positional change of a boundary over time)
The Digital Shoreline Analysis System (DSAS) v5 software is an add-in to Esri ArcGIS desktop (10.4-10.7+) that enables a user to calculate rate-of-change statistics from multiple historical shoreline positions. It provides an automated method for establishing measurement locations, performs rate calculations, provides the statistical data necessary to assess the robustness of the rates, and includes a beta model of shoreline forecasting with the option to generate 10 and/or 20-year shoreline horizons and uncertainty bands. A user-friendly interface guides the user through the major steps of shoreline change analysis. An in-depth user guide and video tutorials are available that provide detailed instruction on the DSAS workflow including: how to define a reference baseline for measurements, the steps needed to generate automated measurement transects and metadata based on user-specified parameters, guidelines on how to manually add or edit existing transects, and an explanation of the visualization options to display calculated rates of shoreline change and other statistical informatio
DSAS software is used to calculate shoreline or boundary change over time. To download the free Add-in, click below:
The newest DSAS v5.1 user guide provides detailed instructions for the implementation of DSAS software.
Introduction video to DSAS system requirements and installation and a demonstration video to help end users produce rates of shoreline change.
DSAS version 5.1 was released in November 2021 and is publicly available here. Click on the file "DSASAddin_v5.1.zip"" to download the Esri add-in file. The supporting DSAS version 5.1 User Guide (found here) contains Installation procedures, system requirements, and detailed instructions for use. Available help resources include an instructional video for System Requirements and Installation, as well as a tutorial detailing a Sample Data Workflow. For additional questions please contact DSAS_help@usgs.gov
This update builds on the capabilities of the previous version—DSAS v5.0 (Himmelstoss and others, 2018). Updates from the original in version 5.1 include the following:
Advanced baseline placement options: Baselines located onshore, offshore, midshore (new!) or any combination of baseline orientations are now accepted.
Attribute Automator: a tool for easily adding required and optional attribute fields to shoreline and baseline data.
Rates returned as feature class: rate information is automatically spatially joined to DSAS transects for faster visualization.
Data visualization: rates of change are added to the map view with pre-set color ramps for rapid display and interpretation of results.
Beta shoreline forecasting: future shoreline horizons calculated with uncertainty bands for advanced interpretation of forecasted changes.
Summary report: a text file is generated each time rate calculations are run capturing all DSAS settings, input data used for analysis, and a detailed summary of statistics including overall averages, maximum and minimum, as well as averaged erosion and accretion.
Bias Feature: The optional proxy-datum bias information will no longer be stored as a table: it is now stored and accessed by DSAS through a polyline feature class
Update to location of land relative to baseline data: In the Default Parameters window, Baseline Settings tab, there is a new visualization symbol to assist users in identifying the orientation of land relative to baseline data, left (L) or right (R)
There are many great resources to help navigate DSAS. We recommend starting with the User Guide, and taking the time to watch the available help videos. Downloading sample data in conjunction with the available guides is great way to familiarize yourself with DSAS. For additional questions or issues, feel free to contact us at DSAS_help@usgs.gov.
DSAS generates transects that are cast perpendicular to the reference baseline to intersect shorelines at a user-specified spacing alongshore. DSAS v5 supports a baseline located anywhere—offshore, onshore, in the middle of the shoreline data (midshore), or a combination of baseline placements.
Shoreline Change Envelope (SCE)
Net Shoreline Movement (NSM)
End Point Rate (EPR)
Linear Regression Rate (LRR)
Weighted Linear Regression Rate (WLR)
Supplemental statistics for Linear and Weighted regression:
Confidence Interval (LCI/WCI)
Standard Error (LSE/WSE)
The results of all calculations are output to a new rate feature class with the option to visualize results to a default binning standard or to scale to the extent of the data. Transect length can be autodetected and clipped to the shoreline data extent. Users also have the option to generate a summary text file with averages for the rates calculated.
DSAS has been a central component of the U.S. Geological Survey’s Coastal Change Hazards project, providing a robust suite of regression rates in a standardized and easily repeatable method that can be executed on large volumes of data collected at a national scale. The DSAS software is intended to facilitate the shoreline change-calculation process and to provide rate-of-change information and the statistical data necessary to establish the reliability of the calculated results. The software is also suitable for any generic application that calculates positional change over time, such as assessing change of glacier limits in sequential aerial photos, river edge boundaries, or land-cover changes. National and state governments worldwide have used the tool in support of resource management and critical coastal decision-making.
The DSAS software was originally developed in the early 1990’s and has undergone continuous refinement. DSAS version 1.0 (1992) was written in the C and awk programming languages for use with the MapGrafix and ArcInfo Geographic Information Systems. DSAS version 2.0 was written in Avenue for ArcView 3.x. DSAS version 3.x (ArcGIS 9), DSAS version 4.2 (ArcGIS 9) and DSAS version 4.3.4730 (ArcGIS 10) were written in VB.NET using the ArcObjects Object Library for ArcGIS. Each version of DSAS includes many improvements that are described in the documentation. Typically, we concentrate our efforts on improving the rate-of-change statistics and the user interface.
Past (unsupported) DSAS versions are publically available as follows:
Version 4: https://cmgds.marine.usgs.gov/publications/DSAS/of2008-1278/
Version 3: https://cmgds.marine.usgs.gov/publications/DSAS/of2005-1304/
Version 2: https://cmgds.marine.usgs.gov/publications/DSAS/of03-76/
Version 1: https://pubs.usgs.gov/of/1992/0355/report.pdf
Uninstall patch for DSAS version 4.x
This patch is ONLY for DSAS version 4.0-4.3, and for users who uninstalled ArcGIS 9.x before uninstalling DSAS version 4.x. Please note, when upgrading to a new version of ArcGIS, it is best to first uninstall custom ArcGIS extensions (such as DSAS). DSAS was developed using standard Esri-recommended methodology, but unfortunately cannot be removed if ArcGIS has already been uninstalled from the system. If ArcGIS 9.x was uninstalled (typical during a version update to ArcGIS 10) before uninstalling DSAS, the Esri libraries DSAS requires to unregister itself are no longer available. For users who find themselves unable to uninstall DSAS, use this patch.
Conversion utility for DSAS version 2.x
DSAS transects created in DSAS version 2.x (for ArcView 3.x) can now be imported for use in DSAS version 4 using the stand-alone utility available for download here
Below are data releases associated with the DSAS project.
Below are multimedia items associated with this project.
Below are publications associated with this project.