Rate of shoreline change of marsh plains in eastern Long Island salt marsh complex, New York (ver. 3.0, May 2026)

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Metadata:

Identification_Information
Data_Quality_Information
Spatial_Data_Organization_Information
Spatial_Reference_Information
Entity_and_Attribute_Information
Distribution_Information
Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: Robert Welk
Originator: Kate V. Ackerman
Originator: Zafer Defne
Originator: Neil K. Ganju
Publication_Date: 20200331
Title:

Rate of shoreline change of marsh plains in eastern Long Island salt marsh complex, New York (ver. 3.0, May 2026)

Edition: 3.0
Geospatial_Data_Presentation_Form: Vector Digital dataset (Polygon)
Series_Information:

Series_Name: data release
Issue_Identification: 10.5066/P91H426U

Publication_Information:

Publication_Place: Woods Hole Coastal and Marine Science Center, Woods Hole, MA
Publisher:

U.S. Geological Survey, Coastal and Marine Hazards and Resources Program

Online_Linkage: https://doi.org/10.5066/P91H426U
Online_Linkage:

https://www.sciencebase.gov/catalog/item/5ddda8fae4b04a30051ac270

Larger_Work_Citation:

Citation_Information:

Originator: Robert Welk
Originator: Kate V. Ackerman
Originator: Zafer Defne
Originator: Neil Ganju
Publication_Date: 2020
Title:

Coastal wetlands of eastern Long Island, New York (ver. 3.0, May 2026)

Edition: 3.0
Series_Information:

Series_Name: data release
Issue_Identification: 10.5066/P91H426U

Publication_Information:

Publication_Place: Reston, VA
Publisher: U.S. Geological Survey

Other_Citation_Details:

Suggested citation: Welk, R., 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.

Online_Linkage: https://doi.org/10.5066/P91H426U
Online_Linkage:

https://www.sciencebase.gov/catalog/item/5dd56511e4b0695797628ca6

Description:

Abstract:

*In this revision (version 3), the marsh plains were subdivided into smaller marsh units, and metrics were updated to reflect this change. Details can be found in the process steps below. This dataset (shoreline change rate) was not revised; it is included here only to provide shoreline change rates at the marsh plain scale rather than at the marsh unit scale.* This data release contains coastal wetland synthesis products for the geographic region of eastern Long Island, New York, including the north and south forks, Gardiners Island, and Fishers Island. Metrics for resiliency, including unvegetated to vegetated ratio (UVVR), marsh elevation, and mean tidal range, are calculated for smaller units delineated from a Digital Elevation Model, providing the spatial variability of physical factors that influence wetland health. Through scientific efforts initiated with the Hurricane Sandy Science Plan, the U.S. Geological Survey has been expanding national assessment of coastal change hazards and forecast products to coastal wetlands with the intent of providing Federal, State, and local managers with tools to estimate the vulnerability and ecosystem service potential of these wetlands. For this purpose, the response and resilience of coastal wetlands to physical factors need to be assessed in terms of the ensuing change to their vulnerability and ecosystem services.
This dataset displays shoreline change rates for eastern Long Island. Shoreline change rates are based on analysis of digital vector shorelines acquired from historical topographic sheets provided by National Oceanic and Atmospheric Administration (NOAA). Analysis was performed using the Digital Shoreline Analysis System (DSAS), an extension for ArcMap, created by the U.S. Geological Survey. Linear Regression Rates (LRR) and End Point Rates (EPR) of shoreline change were averaged along the shoreline of each salt marsh plain to generate this dataset. LRR rates were used in areas where three or more historical shorelines were available, while EPR was used in areas where only two were available. Positive and negative values indicate accretion and erosion respectively.

Purpose:

Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2020

Currentness_Reference: Publication date of original release.

Status:

Progress: Complete
Maintenance_and_Update_Frequency: None

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -72.748198
East_Bounding_Coordinate: 71.885316
North_Bounding_Coordinate: 41.291362
South_Bounding_Coordinate: 40.766433

Keywords:

Theme:

Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: USGS:5ddda8fae4b04a30051ac270

Theme:

Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: geospatial datasets
Theme_Keyword: wetland ecosystems
Theme_Keyword: wetland functions
Theme_Keyword: coastal ecosystems
Theme_Keyword: coastal processes
Theme_Keyword: tides (oceanic)

Theme:

Theme_Keyword_Thesaurus: None
Theme_Keyword: shoreline
Theme_Keyword: coastline
Theme_Keyword: accretion
Theme_Keyword: sediment
Theme_Keyword: salt marsh
Theme_Keyword: vegetation
Theme_Keyword: marsh health
Theme_Keyword: estuary
Theme_Keyword: resilience
Theme_Keyword: vulnerability
Theme_Keyword: polygon shapefile

Theme:

Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: oceans
Theme_Keyword: inlandWaters
Theme_Keyword: environment

Place:

Place_Keyword_Thesaurus: GNIS
Place_Keyword: Atlantic Ocean
Place_Keyword: State of New York
Place_Keyword: Suffolk County, New York
Place_Keyword: Great Peconic Bay
Place_Keyword: Little Peconic Bay
Place_Keyword: Moriches Bay
Place_Keyword: Shinnecock Bay
Place_Keyword: Long Island Sound

Access_Constraints:

No access constraints. Please see 'Distribution Information' for details.

Use_Constraints:

These data are marked with a Creative Commons CC0 1.0 Universal License. These data are in the public domain and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. 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.

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey
Contact_Person: Robert Welk

Contact_Position: Hydrologic Technician
Contact_Address:

Address_Type: mailing and physical address
Address: 2045 Route 112
City: Coram
State_or_Province: NY
Postal_Code: 11743

Contact_Voice_Telephone: 631-736-0783 x141
Contact_Electronic_Mail_Address: rwelk@usgs.gov

Browse_Graphic:

Browse_Graphic_File_Name:

https://www.sciencebase.gov/catalog/file/get/5ddda8fae4b04a30051ac270?name=ShCR_ELI_browse.png&allowOpen=true

Browse_Graphic_File_Description:

Graphic that shows the shoreline change rate overlaying Esri Map.

Browse_Graphic_File_Type: PNG

Native_Data_Set_Environment:

Environment as of Metadata Creation: Microsoft 10 Version 6.2 (Build 9200); Esri ArcGIS 10.7.1 (Build 11595) Service Pack N/A (Build N/A); and ArcGIS Pro 2.8.8.

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

Water-land boundaries and marsh unit boundaries inherit their accuracy from the source data, the conceptual salt marsh units. Shoreline change rate is calculated by averaging the values from the source layer (shoreline change transects are drawn every ~50 meters along a baseline) for each marsh unit. Shoreline change rates in the source data are influenced by availability and accuracy

Logical_Consistency_Report:

Mean Linear Regression Rate (LRR) and mean End Point Rate (EPR) of shoreline change is calculated by averaging the LRR and EPR transects that cross the shoreline of a marsh unit, respectively. If a marsh unit has a shoreline, but no transect is available to assign a shoreline change rate, the mean LRR and/or mean EPR is set to zero.

Completeness_Report:

The results are specific to the marsh polygons as defined within the boundaries of the eastern Long Island salt marsh complex. A detailed on-the-ground analysis of a single site may result in a different interpretation of the wetland and marsh unit boundaries. All of the marsh units are assigned a value. If MEAN_LRR is 0 for a marsh unit, 0 in the TRANS_PER_L field indicates the marsh unit has no shoreline and -1 indicates there are no transects available. Likewise, if MEAN_EPR is 0 for a marsh unit, 0 in the TRANS_PER_E field indicates the marsh has no shoreline and -1 indicates there are no transects available.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

Horizontal accuracy for the polygon boundaries is inherited from the source layer, the conceptual marsh units and considered to be +/- 6 meters.

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator: Robert Welk
Publication_Date: 2019
Title:

Rate of shoreline change statistics for New York State coastal wetlands

Edition: 1.0
Geospatial_Data_Presentation_Form: Vector Digital dataset (Polyline)
Series_Information:

Series_Name: data release
Issue_Identification: DOI:10.5066/P9JVMLFT

Publication_Information:

Publication_Place: Reston, Virginia
Publisher: U.S. Geological Survey

Online_Linkage: https://doi.org/10.5066/P9JVMLFT

Type_of_Source_Media: Online
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2019

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: LRR_transects
Source_Contribution:

Used the LRR and EPR transects to calculate the shoreline change rates at each marsh unit. Download date was 2019/08/01.

Source_Information:

Source_Citation:

Citation_Information:

Originator: U.S. Fish and Wildlife Service
Publication_Date: 2017
Title: National Wetland Inventory New York Wetlands
Geospatial_Data_Presentation_Form: Vector Digital dataset (Polygon)
Publication_Information:

Publication_Place: Madison, WI
Publisher: U.S. Fish and Wildlife Service

Online_Linkage:

https://www.fws.gov/program/national-wetlands-inventory/download-state-wetlands-data

Type_of_Source_Media: Digital
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2017

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: NWI
Source_Contribution:

Downloaded wetlands data for the state of New York in shapefile format from the NWI download page. Projection was NAD 1983 Albers. Download date was 2019/08/01.

Process_Step:

Process_Description:

This process step and all subsequent process steps were performed in ArcMap (ver. 10.7.1) using tools from ArcToolbox, unless otherwise stated. For complex operations, names of specific tools used are given in CAPITAL letters (any critical parameters used are given in parentheses, separated by a semicolon, immediately after the tool name). The input and output file names are provided in [square brackets] when necessary. Units for length and area calculations are meters (m) and square meters (m2) unless otherwise stated.
Shoreline change rates for the eastern Long Island salt marsh complex are based on "Rate of shoreline change statistics for New York State coastal wetlands" by R. Welk.

Process_Date: 2019
Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey
Contact_Person: Robert Welk

Contact_Position: Hydrologic Technician
Contact_Address:

Address_Type: mailing and physical address
Address: 2045 NY 112
City: Coram
State_or_Province: NY
Postal_Code: 11735

Contact_Voice_Telephone: 631-736-0783 x141
Contact_Electronic_Mail_Address: rwelk@usgs.gov

Process_Step:

Process_Description:

Calculate shoreline length for each marsh unit. a) From NWI, SELECT BY ATTRIBUTES(WETLAND_TY = 'Estuarine and Marine Deepwater') to obtain coastal water polygon features. EXPORT to obtain [NWI_deepwater.shp].
b) DISSOLVE (Input Features = [NWI_deepwater.shp]) to obtain Output Feature Class = [NWI_deepwater_dissolve.shp].
c) BUFFER (Input features=[NWI_deepwater_dissolve.shp]; Linear unit= -5 meters; Dissolve type=All) to obtain [NWI_deepwater_buffern5m.shp].
d) Create a bounding box polygon [bounding_box.shp].
e) ERASE(Input Features=[bounding_box.shp]; Erase Features=[NWI_deepwater_buffern5m.shp]; Output Feature Class=[land_polygon.shp]).
f) ELIMINATE POLYGON PART(Input Features=[land_polygon.shp]; Output Feature Class=[land_polygon_elim.shp]; Condition='Percent'; Percentage=99; Eliminate contained parts only).
g) Revert back to open water polygon by ERASE(Input Features=[bounding_box.shp]; Erase Features=[land_polygon_elim.shp]; Output Feature Class=[open_water_polygon.shp]) and BUFFER(Linear unit= 5 meters) to obtain [open_water_buff5m.shp].
h) DISSOLVE(Input Features = [CMU_ELI.shp]; Dissolve Field=FID_CMU) to obtain [CMU_dissolve.shp] and convert to line feature by POLYGON TO LINE to get [CMU_line.shp]
i) Obtain marsh unit shorelines by INTERSECT(Input Features = [CMU_line.shp] and [open_water_buff5m.shp]; XY Tolerance=1.0 meters; Output Type=LINE) to obtain [mu_shorelines.shp]

Source_Used_Citation_Abbreviation: CMU_ELI.shp
Source_Used_Citation_Abbreviation: NWI
Process_Date: 2019
Source_Produced_Citation_Abbreviation: mu_shorelines.shp

Process_Step:

Process_Description:

Calculate the transect coverage and mean LRR shoreline change in each marsh unit. Transect coverage is the average shoreline length represented by the transects in a marsh unit.
a) EXPORT dissolved marsh unit layer [CMU_dissolve.shp] to obtain [mu_ShRC.shp]
b) SPATIAL JOIN(Target features=[mu_ShRC.shp]; Join features=[LRR_transects.shp]; Output features=[mu_LRR_trans_join.shp];Join_one_to_many; Match option=INTERSECT) to assign LRR values to the intersecting marsh units. Repeat step for EPR transects to obtain [mu_EPR_trans_join.shp].
b) Calculate the mean LRR for each marsh unit with SUMMARY STATISTICS(Input table=[mu_LRR_trans_Join.shp]; Output_table=[s_LRR]; Statistics Fields=LRR; Statistics type=MEAN; Case field='TARGET_FID'). Repeat step for EPR transects to obtain [s_EPR].
c) Join statistics fields to the marsh unit layer using JOIN FIELD(Input Table=mu_ShRC.shp; Input Join Field=FID_CMU; Join Table=s_LRR; Output Join Field=FID_CMU; Join Fields=MEAN_LRR, FREQUENCY). Repeat step for EPR.
d) ADD the TRANS_PER_L field and calculate it as the total shoreline length divided by FREQUENCY. Assign a value of -1 if the number of transects is equal to zero. Repeat step for EPR transects by adding the TRANS_PER_E field and making the same calculation.
e) Edit the attribute table to choose fields to keep and to format the field names. Export the dataset as final output [mu_LRR_EBFNWRp.shp]

Source_Used_Citation_Abbreviation: CMU_dissolve.shp
Source_Used_Citation_Abbreviation: LRR_transects.shp
Source_Used_Citation_Abbreviation: EPR_transects.shp
Process_Date: 2019
Source_Produced_Citation_Abbreviation: mu_shoreline_ELI.shp

Process_Step:

Process_Description:

Added keywords section with USGS persistent identifier as theme keyword.

Process_Date: 20200806
Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey
Contact_Person: VeeAnn A. Cross

Contact_Position: Marine Geologist
Contact_Address:

Address_Type: Mailing and Physical
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598

Contact_Voice_Telephone: 508-548-8700 x2251
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: vatnipp@usgs.gov

Process_Step:

Process_Description:

Version 2 updates. Updates were performed in ArcGIS Pro 2.8.8. Duplicate marsh units were manually identified and compared to make sure the most appropriate duplicate marsh unit was deleted. Seventy-six duplicate marsh units were identified (out of 2828) in Mecox Bay, Sagaponack Pond and Georgica Pond and have been removed. After the duplicate marsh units were deleted, the elevation, hydroflattened percentage and elevation flag values were recalculated. Authorship was updated to include Kate Ackerman.

Process_Date: 20240116
Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Kate Ackerman
Contact_Organization: U.S. Geological Survey

Contact_Position: Geologist
Contact_Address:

Address_Type: mailing address
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543
Country: US

Contact_Voice_Telephone: 508-548-8700 x2331
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: kackerman@usgs.gov

Process_Step:

Process_Description:

Version 3 Updates. All updates were completed in ArcGIS Pro 3.4.3, using the version 2 of the dataset as the starting dataset. 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. Using the new marsh units, UVVR and elevation values were recalculated. Tide range values were carried over from the original (larger) marsh plain polygons and applied to the new, smaller marsh units.
However, 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." 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. Previous versions of the data can be obtained by contacting whsc_data_contact@usgs.gov.

Process_Date: 20260501
Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Kate Ackerman
Contact_Organization: U.S. Geological Survey

Contact_Position: Geologist
Contact_Address:

Address_Type: mailing address
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543
Country: US

Contact_Voice_Telephone: 508-548-8700 x2331
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: kackerman@usgs.gov

Process_Step:

Process_Description:

Change the name of the FID_CMU field to "MP", for "marsh plain" since these polygons refer to marsh plains rather than marsh units. Also changed the name of the shapefile from "mu_shoreline_ELI" to "mp_shoreline_ELI."

Process_Date: 2026
Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Kate Ackerman
Contact_Organization: U.S. Geological Survey

Contact_Position: Geologist
Contact_Address:

Address_Type: mailing address
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543
Country: US

Contact_Voice_Telephone: 508-548-8700 x2331
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: kackerman@usgs.gov

Process_Step:

Process_Description:

Removed the web services distribution formats in preparation for ScienceBase moving platforms and those services no longer being available.

Process_Date: 20260501
Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Kate Ackerman
Contact_Organization: U.S. Geological Survey

Contact_Position: Geologist
Contact_Address:

Address_Type: mailing address
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543
Country: US

Contact_Voice_Telephone: 508-548-8700 x2331
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: kackerman@usgs.gov

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Vector
Point_and_Vector_Object_Information:

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: G-polygon
Point_and_Vector_Object_Count: 2752

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Map_Projection:

Map_Projection_Name:

WGS 1984 Web Mercator Auxiliary Sphere (ESRI Full Name: WGS_1984_Web_Mercator_Auxiliary_Sphere)

Mercator:

Standard_Parallel: 0.0
Longitude_of_Central_Meridian: 0.0
False_Easting: 0.0
False_Northing: 0.0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:

Abscissa_Resolution: 0.6096
Ordinate_Resolution: 0.6096

Planar_Distance_Units: Meter

Geodetic_Model:

Horizontal_Datum_Name: D_WGS_1984
Ellipsoid_Name: WGS_1984
Semi-major_Axis: 6378137.0
Denominator_of_Flattening_Ratio: 298.257223563

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: mp_shoreline_ELI
Entity_Type_Definition:

Table containing attribute information associated with the dataset.

Entity_Type_Definition_Source: USGS

Attribute:

Attribute_Label: FID
Attribute_Definition: Internal feature number.
Attribute_Definition_Source: Esri
Attribute_Domain_Values:

Unrepresentable_Domain:

Sequential unique whole numbers that are automatically generated.

Attribute:

Attribute_Label: Shape
Attribute_Definition: Feature geometry.
Attribute_Definition_Source: Esri
Attribute_Domain_Values:

Unrepresentable_Domain: Coordinates defining the features.

Attribute:

Attribute_Label: MP
Attribute_Definition:

Unique whole number that represents the identification number for each polygon, or "marsh plain". In revision 3.0, this field was changed from "FID_CMU" to "MP."

Attribute_Definition_Source: USGS
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 2
Range_Domain_Maximum: 3455

Attribute:

Attribute_Label: MEAN_LRR
Attribute_Definition:

Shoreline change rate based on a linear regression. A zero value may indicate: a) the rate of change is actually zero, b) the marsh unit does not have a shoreline (SHORE_LEN=0), or c) no transect is available for calculation (TRANS_PER_L=-1).

Attribute_Definition_Source: USGS
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -0.96
Range_Domain_Maximum: 2.32
Attribute_Units_of_Measure: meters/year

Attribute:

Attribute_Label: MEAN_EPR
Attribute_Definition:

Mean shoreline change rate based on an end-point method. A zero value may indicate: a) the rate of change is actually zero, b) the marsh unit does not have a shoreline (SHORE_LEN=0), or c) no transect is available for calculation (TRANS_PER_I=-1).

Attribute_Definition_Source: USGS
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -0.97
Range_Domain_Maximum: 1.36
Attribute_Units_of_Measure: meters/year

Attribute:

Attribute_Label: SHORE_LEN
Attribute_Definition: Shoreline length
Attribute_Definition_Source: USGS
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0
Range_Domain_Maximum: 5319.578975
Attribute_Units_of_Measure: meters

Attribute:

Attribute_Label: TRANS_PER_L
Attribute_Definition:

Average shoreline length represented per LRR transect. Calculated by dividing SHORE_LEN by number of LRR transects. A value of -1 indicates no LRR transect is available, and a value of 0 means the marsh unit has no shoreline.

Attribute_Definition_Source: USGS
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.034619
Range_Domain_Maximum: 793.854658
Attribute_Units_of_Measure: meters

Attribute:

Attribute_Label: TRANS_PER_E
Attribute_Definition:

Average shoreline length represented per EPR transect. Calculated by dividing SHORE_LEN by number of EPR transects. A value of -1 indicates no LRR transect is available, and a value of 0 means the marsh unit has no shoreline.

Attribute_Definition_Source: USGS
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.053653
Range_Domain_Maximum: 313.531974
Attribute_Units_of_Measure: meters

Attribute:

Attribute_Label: FLG
Attribute_Definition:

Marsh unit flag indicating anomalous marsh units based on elevation, surface area, and absence of vegetation. FLG values indicate: (-1) no vegetated area; (-10) marsh unit elevation higher than the 99.8 percentile; (-100) marsh unit elevation less than 0.2 percentile; (-200) greater than 25% of marsh unit has hydroflattened area and has -9999 as its elevation value; (-1000) marsh unit surface area less than 900 m2; and (0) no flag. Combination of negative values indicate combination of flags. For example, -1001 indicates no vegetated area and area less than 900 m2.

Attribute_Definition_Source: USGS
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -11201
Range_Domain_Maximum: 0
Attribute_Units_of_Measure: None

Overview_Description:

Entity_and_Attribute_Overview:

In this dataset, shoreline change rates are averaged over each marsh plain polygon in eastern Long Island. Negative and positive values indicate erosion and accretion, respectively. Decimal values in the attribute table are a result of double precision calculations while significant digits are considered in defining the attribute measurement resolutions. Therefore, the smallest unit increment for shoreline change rate values can be assumed to be a practical value such as 0.01 meters/year.

Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey - ScienceBase

Contact_Address:

Address_Type: mailing and physical address
Address: Denver Federal Center, Building 810, Mail Stop 302
City: Denver
State_or_Province: CO
Postal_Code: 80225

Contact_Voice_Telephone: 1-888-275-8747
Contact_Electronic_Mail_Address: sciencebase@usgs.gov

Resource_Description:

mp_shoreline_ELI.shp (and files associated with a shapefile), browse graphic, and CSDGM metadata in XML format.

Distribution_Liability:

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. 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.

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: shapefile
Format_Version_Number: ArcGIS Pro 2.8.8
Format_Information_Content:

This dataset contains a polygon shapefile and its components and metadata in xml format

Transfer_Size: 20

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name:

https://www.sciencebase.gov/catalog/file/get/5ddda8fae4b04a30051ac270

Network_Resource_Name:

https://www.sciencebase.gov/catalog/item/5ddda8fae4b04a30051ac270

Network_Resource_Name: https://doi.org/10.5066/P91H426U

Access_Instructions:

The first link in network resources is to download data directly. The second link points to a landing page with metadata and data. The third link is to the main page of the data release.

Fees: None. No fees are applicable for obtaining the dataset.

Metadata_Reference_Information:

Metadata_Date: 20260519
Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey, Northeast Region
Contact_Person: Robert J Welk

Contact_Position: Hydrologic Technician
Contact_Address:

Address_Type: mailing address
Address: 2045 Route 112
City: Coram
State_or_Province: NY
Postal_Code: 11727
Country: US

Contact_Voice_Telephone: 631-736-0783 x141
Contact_Electronic_Mail_Address: 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_Name: FGDC Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998

This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P91H426U/mp_shoreline_ELI.html>