Revision for U.S. Geological Survey data release:

Welk, R.J., Ackerman, K.V., Defne, Z., and Ganju, N.K., 2020, Coastal wetlands of eastern Long Island, New York (ver. 3.0, May 2026): U.S. Geological Survey data release, https://doi.org/10.5066/P91H426U.

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Version 1 posted online March 31, 2020
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Revised and reposted, March 12, 2024 as version 2.0

Changes in version 2.0:
1) Some of the marsh units had duplicates in the original data release. In this version these have been removed. A total of 76 units (out of 2828) in Mecox Bay, Sagaponack Pond and Georgica Pond have been removed.
2) Subsequently the elevation, hydroflattening percentage and flag values have been recalculated. Updated fields included MU_ELEV, VG_ELEV, AVEG_M2 and FLG. 
3) Authorship was updated to include Kate Ackerman.

Revisions were done by Ackerman, K.V., USGS Woods Hole Coastal and Marine Science Center.


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Revised and reposted, May 19, 2026 as version 3.0

Changes in version 3.0: 
1) In the original dataset, each marsh plain was not subdivided into smaller parcels (“marsh units”) because two processing steps were not completed. For Version 3, these processing steps were completed, resulting in each marsh plain being properly subdivided into these smaller marsh units.
2) Using the new marsh units, UVVR and elevation values were recalculated.  
3) Tide range values were carried over from the original (larger) marsh plain polygons and applied to the new, smaller marsh units.  
4) Exposure potential (SCoRR) values and shoreline change values could not be recalculated at the marsh unit scale. They remain unchanged and still represent the larger marsh plain polygons. In the SCoRR and shoreline change datasets, the field FID_CMU has been renamed to MP to indicate that those polygons correspond to marsh plains, not the newly created marsh units. In the title of the data release for exposure potential and shoreline change, the words "marsh units" were changed to "marsh plains." The name of the shapefiles were changed from "mu_shoreline_ELI" to "mp_shoreline_ELI," and from "mu_SCoRR_ELI" to "mp_SCoRR_ELI." Throughout the exposure potential and shoreline change metadata, the term 'marsh unit' is still used, but readers should understand that it actually refers to the marsh plain.

Revisions were done by K.V. Ackerman, USGS Woods Hole Coastal and Marine Science Center.

Earlier versions are available by contacting whsc_data_contact@usgs.gov