Digital Shoreline Analysis System (DSAS)

Digital Shoreline Analysis System

Digital Shoreline Analysis System

The Digital Shoreline Analysis System (DSAS) software

Download software

Science Center Objects

Computer Software for Calculating Shoreline Change (or positional change of a boundary over time)

The Digital Shoreline Analysis System (DSAS) is an add-in to Esri ArcGIS desktop v. 10.4-10.6 that enables a user to calculate shoreline 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 of simple buttons and menus guides the user through the major steps of shoreline change analysis. Components of the extension and user guide include instruction on the proper way to define a reference baseline for measurements, automated and manual generation of measurement transects and metadata based on user-specified parameters, and an explanation of the options to visualize the output of calculated rates of shoreline change and other statistical information.


Current Version for ArcGIS 10.4- 10.6

DSAS version 5.0 was released in December 2018 and the Esri add-in is available for free here.  Click on "" to download the file. The supporting DSAS version 5.0 User Guide (found here) contains Installation procedures, system requirements, and detailed instructions for use.  For any questions regarding DSAS version 5.0 that you are unable to find answers to within the user guide, please contact


Uninstall patch for DSAS version 4.x

This patch is ONLY 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

DSAS transects created in the previous DSAS version 2x (for ArcView 3.x) can now be imported for use in DSAS version 4 using the stand-alone utility available for download at here

    The results of all rate 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 is autodetected and scaled to the shoreline data extent. Users also have the option to generate a summary text file with averages for the rates calculated.

    DSAS generated transect

    DSAS generates transects that are cast perpendicular to the reference baseline at a user-specified spacing alongshore.  There are no restrictions on where the reference baseline is drawn, it may be positioned completely to one side of the shoreline data or be placed between the historical shoreline positions.  DSAS measures the distance between the baseline and each shoreline intersection along a transect, and combines date information, and positional uncertainty for each shoreline to generate the following change metrics:

    Distance measurements:

    • Shoreline Change Envelope (SCE)
    • Net Shoreline Movement (NSM)


    • End Point Rate (EPR)
    • Least Regression Rate (LRR)
    • Weighted Least Squares Regression (WLR)

    Supplemental statistics for Least and Weighted regression:

    • Confidence Interval (LCI/WCI)
    • Standard Error (LSE/WSE)
    • R-squared (LR2/WR2)
    Displaying fixed bin options for rates of change

    Displaying fixed bin options (left) for rates of change for an example dataset (LRR, EPR, WLR), and scaled to data (right) (NSM).

    The DSAS add-in is 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.  DSAS 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 critical coastal decision-making and policy.

    Data visualization with scaled options applied

    Data visualization with (A) fixed and (B) scaled options applied. Examples of NSM and SCE are also displayed (C and D respectively). The data itself has not changed – only the scaling and statistic selected through the DSAS Data Visualization tool.


    The DSAS software was originally developed in the early 1990’s and has undergone continuous, albeit episodic 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.