Description of the data and file structure
This dataset includes 1938 aerial photographs and the forest edges, shorelines, and baselines used in the Digital Shoreline Analysis System (DSAS) to produce transects and measure erosion and migration rates. This also includes spatial data of environmental variables including
slope, topographic position index (TPI), marsh width, soil drainability,
fecal coliform concentrations, salinity, and tidal range. Datasets
connecting each of the erosion and migration transects to each of the
environmental factors in this study are included. The random points and
transects used in the error analysis are also included. These were used
to quantify uncertainty in boundary position and error arising from
georeferencing misalignment. All shapefiles and TIFs are in the NAD 1983
UTM Zone 18N projected coordinate system. All .zip files include CPG,
DBF, PRJ, SBN, SBX, SHP, XML, and SHX files.

Files and variables
File: 1938AerialImageryTIFFs.zip
Description: Historical photos (June & July, 1938) of the Long
Island South Shore which were collated and georeferenced in ArcGIS Pro
(version 3.5.3, ESRI, Redlands, CA, USA) using a first-order polynomial
transformation, with a minimum of six control points per image tile
located using persistent features such as road intersections and
historic structures.

File: FinalForestEdge1938.zip
Description: Marsh-forest edge shapefiles created using a
semi-automated digitization of habitat boundaries utilizing historical
(1938) aerial photography. Boundaries were hand-digitized using visual
inspection at a 1:2000 scale with dense tree stands being used to define
forests. After converting image-objects to polylines, we selected those
within 20 m of the hand-digitized marsh–forest edge, generated a 10
meter buffer around the selected segments to derive a midpoint
centerline, and then connected these centerlines to produce a continuous
forest-edge line.

Variables
FID: Feature ID (unique identifier for each section of marsh-forest
edge) Shape: Each of these forest edges are polylines Shape_Length:
Length of each polyline in meters Date: Year of the marsh-forest edge
(1938)