Conceptual marsh units of eastern Long Island salt marsh complex, New York

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Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: Robert Welk
Originator: Zafer Defne
Originator: Neil Ganju
Publication_Date: 20200331
Title:
Conceptual marsh units of eastern Long Island salt marsh complex, New York
Edition: 1.0
Geospatial_Data_Presentation_Form: Vector Digital dataset (Polygon)
Series_Information:
Series_Name: data release
Issue_Identification: DOI: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 Geology Program
Online_Linkage: https://doi.org/10.5066/P91H426U
Online_Linkage: Larger_Work_Citation:
Citation_Information:
Originator: Robert Welk
Originator: Zafer Defne
Originator: Neil Ganju
Publication_Date: 2020
Title: Coastal wetlands of eastern Long Island, New York
Edition: 1.0
Series_Information:
Series_Name: data release
Issue_Identification: DOI:10.5066/P91H426U
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Other_Citation_Details:
Suggested citation: Welk, R., Defne, Z., and Ganju, N.K., 2020, Coastal wetlands of eastern Long Island, New York: U.S. Geological Survey data release,https://doi.org/10.5066/P91H426U.
Online_Linkage: https://doi.org/10.5066/P91H426U
Online_Linkage:
Description:
Abstract:
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.
Purpose:
These polygons were created to be used in evaluating the spatial variation of the response and resiliency of the salt marsh complex based on consistently defined marsh units while facilitating a better understanding of the relative importance of the processes involved. The salt marsh complex of eastern Long Island was delineated to smaller, conceptual marsh units by the geoprocessing of surface elevation data. Flow accumulation based on the relative elevation of each location is used to determine the ridge lines that separate each marsh unit while the surface slope is used to automatically assign each unit a drainage point, where water is expected to drain through.
Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2020
Currentness_Reference: Publication date
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:5ddd57c1e4b06957976c91fc
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:
Theme_Keyword_Thesaurus: None
Theme_Keyword: salt marsh
Theme_Keyword: vegetation
Theme_Keyword: marsh health
Theme_Keyword: estuary
Theme_Keyword: Long-Term Ecological Research
Theme_Keyword: LTER
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: oceans
Theme_Keyword: inlandWaters
Theme_Keyword: environment
Place:
Place_Keyword_Thesaurus: None
Place_Keyword: Atlantic Ocean
Place_Keyword: United States
Place_Keyword: New York
Place_Keyword: Suffolk County
Place_Keyword: Peconic Bay
Place_Keyword: Moriches Bay
Place_Keyword: Shinnecock Bay
Place_Keyword: Long Island Sound
Access_Constraints: None
Use_Constraints:
These polygons are defined for scientific research purposes and should not be used as a sole source of reference for any regulations and policy making. 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 source of this information.
Point_of_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: rwelk@usgs.gov
Browse_Graphic:
Browse_Graphic_File_Name: Browse_Graphic_File_Description:
Graphic that shows conceptual marsh units overlaying ESRI basemap.
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)
Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
Marsh units and water and land boundaries inherit their accuracy from the 2017 U.S. Fish and Wildlife Service National Wetland Inventory (USFWS NWI. However, the lineage of the source data indicates that the underlying data span multiple years and the mapped features may have changed since the date of imagery. Accuracy of marsh unit delineation depends on the vertical and horizontal accuracy of the 1-meter resolution U.S. Geological Survey National Elevation Database (USGS NED) data from 2015. Accuracy of the vegetated and unvegetated polygons is based on the 1-meter resolution National Agriculture Imagery Program (NAIP) products from 2017. Any vegetated or unvegetated polygons less than 9 square meters were merged with the surrounding majority class. When creating marsh units, conterminous polygons smaller than 900 square meters were merged with the larger polygon of the same type. Since small marsh islands are common in eastern Long Island, many polygons in this dataset could not be merged with larger units.
Logical_Consistency_Report:
Topological errors that occurred during geoprocessing were automatically removed by the topological rules used for the analysis. The polygons were checked for correct geometry and do not overlap. Small polygons (less than 9 square meters) were assumed to be marginal and were assigned the classification from the surrounding majority value. This resulted in polygons that were removed from the dataset and FID CMU values that are not sequential. A visual comparison between NAIP imagery was performed at randomly selected sites to verify the land and water boundaries.
Completeness_Report:
The marsh polygons are bound to the borders of the eastern Long Island estuarine intertidal areas that include 1) emergent wetlands, 2) scrub-shrub areas, 3) rooted vascular aquatic beds, 4) organic unconsolidated shores, and 5) channels of open water that are wider than 10 meters. Sliver polygons of open salt water along the marsh edges may also be included in some instances as a result of geoprocessing. A detailed on-the-ground analysis of a single site may result in a different interpretation of the wetland and marsh unit boundaries than those established through this analysis.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Horizontal accuracy is inherited from NED Digital Elevation Models. Vegetated and unvegetated polygons were based on the 1-meter resolution NAIP imagery. Although the analyses were performed at 1-meter resolution, the horizontal accuracy is superseded by NAIP imagery accuracy which is +/-6 meters.
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
Because the elevation values are averaged over delineated polygons, vertical accuracy depends on both the horizontal accuracy of the NWI dataset and the vertical accuracy of the source elevation data, NED. NED vertical elevation accuracy was 0.2 meters.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: 2015
Title: National Elevation Dataset
Geospatial_Data_Presentation_Form: Raster Digital dataset
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Online_Linkage: https://nationalmap.gov/viewer.html
Type_of_Source_Media: Digital
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2015
Source_Currentness_Reference: publication date
Source_Citation_Abbreviation: NED
Source_Contribution:
Downloaded NED Digital Elevation Model from the National Map. Projection was NAD 1983 UTM Zone 18N with the North American Vertical Datum of 1988 (NAVD 88). Download date was 2019/08/01.
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: 2017
Title: NAIP Digital Ortho Photo Image
Geospatial_Data_Presentation_Form: Remote-sensing image
Publication_Information:
Publication_Place: Salt Lake City, Utah
Publisher: USDA-FSA-APFO Aerial Photography Field Office
Online_Linkage: https://earthexplorer.usgs.gov
Online_Linkage:
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: NAIP
Source_Contribution:
Downloaded NAIP 1-meter resolution imagery from the USGS Earth Explorer. Projection was WGS 1984 Web Mercator Auxiliary Sphere. 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/wetlands/data/Data-Download.html
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.
Source_Information:
Source_Citation:
Citation_Information:
Originator:
New England Interstate Water Pollution Control Commission prepared by Cameron Engineering and Associates, LLP
Publication_Date: 2015
Title: Long Island Tidal Wetlands Trends Analysis
Geospatial_Data_Presentation_Form: Vector Digital Data Set (Polygon)
Online_Linkage: http://www.dec.ny.gov/lands/5113.html
Type_of_Source_Media: Digital
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2015
Source_Currentness_Reference: publication date
Source_Citation_Abbreviation: NYSDEC
Source_Contribution:
Wetland polygon shapefile prepared for Long Island Tidal Wetlands Trends Analysis. Data available by request. Data acquired 2019/05/01.
Process_Step:
Process_Description:
This process step and all subsequent process steps were performed by the same person, Robert Welk, 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.
Set the data frame coordinate system and projection to NAD 1983 UTM Zone 18N. Prepare elevation dataset to be clipped to the boundaries polygon. MOSAIC TO NEW RASTER(Pixel type= 32 bit float; Mosaic operator=Mean; Cellsize=1 m) the entire NED raster to a new raster dataset with 1 m resolution [elev_mosaic.tif].
Source_Used_Citation_Abbreviation: NED
Process_Date: 2019
Process_Step:
Process_Description:
Prepare mask polygon to define analysis boundaries. In order to account for the possible influence of the surrounding terrain on the analysis, a mask area larger than the salt marsh extent is first created [UVVR_mask]. At the end of the analysis the results are clipped to the boundaries of the salt marsh area [MU_mask]. Both UVVR_mask and MU_mask are edited to determine which interior polygons are removed.
a) MERGE NWI wetland polygons with NYSDEC to obtain [NWI_DEC.shp].
b) EXPORT features from NWI_DEC.shp dataset after SELECT("ATTRIBUTE" LIKE 'E2%EM%' OR "ATTRIBUTE" LIKE 'E2AB3%' OR "ATTRIBUTE" LIKE 'E2EM%' OR "ATTRIBUTE" LIKE 'E2SS%' OR "ATTRIBUTE" LIKE 'E2US4%') to select from estuarine intertidal areas of 1) emergent wetland, 2) scrub-shrub area, 3) rooted vascular aquatic bed, 4) organic unconsolidated shore classes [NWI_exclusive_select.shp].
c) BUFFER(Input features=[NWI_exclusive_select.shp]; Linear unit=5 meters; Dissolve type=All) to obtain the mask polygon [buff5m.shp] and ELIMINATE POLYGON PART(Condition=Percentage; Percentage=99; Eliminate contained part only) to obtain [UVVR_mask01.shp]. Apply buffer with -5 meters to obtain [MU_mask01.shp].

d) EXPORT features from NWI dataset after SELECT("ATTRIBUTE" NOT LIKE 'E%' OR "ATTRIBUTE" LIKE '%FO') to obtain features that are not estuarine or are forested estuarine. MULTIPART TO SINGLEPART to separate individual polygons [NWI_inclusive_single.shp].
e) To exclude the voids in the NWI map during the analysis, these interior polygons need to be removed from the mask. Create a rectangular polygon that covers the domain [extent.shp]. ERASE [NWI_excusive_select.shp] from [extent.shp] and MULTIPART TO SINGLEPART to get [NWI_voids_single.shp].
f) SELECT BY LOCATION from [NWI_inclusive_single.shp] that are completely within the [MU_mask01.shp] and SELECT BY LOCATION from [NWI_voids_single.shp] that are completely within the [MU_mask01.shp]. If any of additional polygons need to be removed from the mask include them in a new feature layer [erase_mask_manual.shp]. Merge all three feature sets to get polygons to be excluded [erase_inside.shp] from the final masks.
g) ERASE [erase_inside.shp] from [MU_mask01.shp] and [UVVR_mask01.shp] to obtain [MU_mask.shp] and [UVVR_mask.shp], respectively.
Source_Used_Citation_Abbreviation: NWI
Source_Used_Citation_Abbreviation: NYSDEC
Process_Date: 2019
Process_Step:
Process_Description:
Define preliminary boundaries for marsh units by basin analysis:
a) EXTRACT BY MASK from mosaicked elevation dataset using [UVVR_mask.shp] polygon.
b) FILL(no Z limit) sinks in extracted elevation raster.
c) Calculate FLOW DIRECTION(do not force edge cells to flow outward) raster.
d) Calculate BASIN based on flow direction raster [basin_buff5m.tif].
e) Apply MAJORITY FILTER(Number of neighbors=8) to clean the raster and convert RASTER TO POLYGON. CLIP the polygon with 1-meter buffered marsh units mask [MU_mask_buff1m.shp]. This additional buffer is necessary to prevent any polygon smoothing algorithm from changing the exterior boundaries and will be removed by clipping to the [MU_mask.shp] later. MULTIPART TO SINGLEPART and ADD GEOMETRY ATTRIBUTES(Geometry properties=Area_geodesic; Area unit=Square_meters) to get [basin_single.shp]
Process_Date: 2019
Process_Step:
Process_Description:
This step merges the "orphan marsh units", units that are less than 5000 m2 in area to the nearest to "parent marsh units", units that are larger than 5000 m2 to obtain the preliminary marsh units. A Python script that iteratively calls a list of ArcMap tools to aggregate orphan units on parent units is used:
a) Create orphan marsh units features by exporting marsh units with an area less than 5000 m2 [lt5000.shp].
b) Create parent marsh units features by exporting marsh units with an area greater than or equal to 5000 m2 [ge5000.shp].
c) Run Python script (hydUnitloop.py). At each iteration step, the script uses NEAR tool to find orphan marsh units within 1 m of a parent marsh unit and merges them to the parent using UNION and DISSOLVE tools. The orphan units merged with a parent unit are removed from the orphan units dataset. Script will iterate until there is no change in the number of parent or orphan marsh units.
d) The remaining orphan marsh units are those that are more than 1 m away from any parent. DISSOLVE them to create larger orphan units by grouping the orphans attached together into larger units.
e) MULTIPART TO SINGLEPART to have single part polygons with unique identifiers.
f) UNION(with gaps) single part features with parent units to obtain preliminary marsh units [pMUopt1.shp].
g) SMOOTH POLYGON(Smoothing algorithm=PAEK; Smoothing tolerance=15 meters) to get the smoothed marsh units polygon [pMUopt1_smooth.shp].
h) CLIP the extra buffer around the smoothed marsh units using the marsh units mask, [MU_mask.shp]. If this results in any additional marsh units with an area less than 5000 m2, dissolve into the nearest parent units repeating the same steps above to obtain [pMUopt1_clip_final.shp]
i) Compute the final marsh units by removing any artefacts from [pMuOpt1_clip_final.shp] using ELIMINATE and REPAIR GEOMETRY tools. ELIMINATE(Expression="Area_geo" less than 900; Eliminating by border) polygon slivers smaller than 900 m2 by merging them to the main polygon. MULTIPART TO SINGLEPART to get conceptual marsh units [CMU.shp]. This only applies to polygons that are bordering other polygons. Polygons that are not bordering other polygons are not affected as those are more likely to be real features as opposed to geoprocessing artefacts.
j) DISSOLVE the conceptual marsh units to get the final outlines for the marsh complex [CMU_mask_final.shp].
Process_Date: 2019
Process_Step:
Process_Description:
Determine the vegetated and unvegetated areas by image processing.
a) EXTRACT BY MASK from elevation raster [elev_mosaic.tif] using [UVVR_mask.shp] polygon. Rescale the elevation raster values to the same range with 8-bit NAIP imagery (0 to 255) using min-max scaling. Perform ISO CLUSTER UNSUPERVISED CLASSIFICATION with4-bands (Near Infrared, Blue, Green, and Red from the NAIP imagery and the rescaled elevation raster with 32 classes and a minimum class size of 5000 cells. RECLASSIFY the classified raster by visually comparing the NAIP imagery to obtain the unvegetated-vegetated raster [UVVc.tif]. For marsh units with invalid elevation data, the classification was processed with imagery bands only and later merged with the rest of the dataset.
b) Dissolve unvegetated regions smaller than a threshold value to the surrounding vegetated regions and vice versa to clean the UVV raster. For this purpose use the REGION(Number of neighbors=4; Zone grouping method=Within; Add Link field to output) to get the [UVV_region.tif], and TEST("Count" less than 9) to set a threshold value of 9 raster cells [UVV_test.tif]. Use RASTER CALCULATOR to toggle the value of the Link field in the region raster, where the test raster indicates regions with areas smaller than the threshold.
c) RASTER TO POLYGON(Simplify polygons=False) and CLIP with the final marsh complex outline [CMU_mask_final.shp] to obtain [UVVc_filt_clip.shp].
d) REPAIR GEOMETRY and DISSOLVE(Create multipart features=False) to get filtered, clipped and dissolved unvegetated-vegetated polygons [UVVc_filt_clip_diss.shp].
e) INTERSECT the final conceptual marsh units [CMU.shp] with unvegetated-vegetated polygons [UVVc_filt_clip.shp], REPAIR GEOMETRY, and calculate the area of unvegetated and vegetated polygons in each marsh unit. To do this ADD GEOMETRY ATTRIBUTES(Geometry properties=Area_geodesic; Area unit=Square_meters) to get [UVV_poly.shp], and DISSOLVE(Input features=UVV_poly.shp; Dissolve fields=FID_CMU, gridcode; Statistics field=gridcode.MEAN, Area_geo.SUM) and REPAIR GEOMETRY to get [UVV_poly_diss.shp]. Edit the fields to have "TYP", "APGN_M2", and "ATOT_M2" fields for type of polygon indicating vegetated or unvegetated, surface area of the polygon, and total surface area of the marsh unit, respectively.
f) Add field "UVVR" and calculate unvegetated to vegetated ratio based on "TYP", "APGN_M2" and "ATOT_M2" fields. If the vegetated area is zero for a marsh unit set the value of UVVR to -1.
g) Calculate the mean elevation for each marsh unit with ZONAL STATISTICS AS TABLE(Raster layer=[elev_mosaic.tif]; Zone features=[CMU.shp], Zone field=FID_CMU; Statistics type=Mean; Ignore Nodata=True) and JOIN with [CMU.shp] to get [mu_elev.shp].
Source_Used_Citation_Abbreviation: NAIP
Process_Date: 2019
Process_Step:
Process_Description:
Finalize the conceptual marsh units.
a) Add field "FLG" to flag anomalous marsh units based on elevation, surface area, and absence of vegetation. Set FLG to (-1) no vegetated area; (-10) marsh unit elevation higher than the 99.8th percentile; (-100) marsh unit elevation less than 0.2th percentile; (-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.
b) Remove field "UVVR" and rearrange field names and change the projection for better performance of web services with online base maps. PROJECT(Input coordinate system=NAD 1983 UTM Zone 18N; Output coordinate system=WGS 1984 Web Mercator Auxiliary Sphere; Geographic transformation=WGS 1984 (ITRF00) to NAD 1983) the feature dataset to obtain the final conceptual marsh units [CMU_ELI.shp].
Process_Date: 2019
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
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: 5274
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: CMU_ELI
Entity_Type_Definition:
Table containing attribute information associated with the dataset.
Entity_Type_Definition_Source: U.S. Geological Survey
Attribute:
Attribute_Label: FID
Attribute_Definition: Internal feature number.
Attribute_Definition_Source: Esri
Attribute_Domain_Values:
Unrepresentable_Domain: 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: FID_CMU
Attribute_Definition:
Unique whole numbers used to identify each conceptual marsh unit. These numbers are duplicated when a marsh unit has both vegetated and unvegetated sub-polygons.
Attribute_Definition_Source: USGS
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 0
Range_Domain_Maximum: 3455
Attribute_Units_of_Measure: none
Attribute:
Attribute_Label: TYP
Attribute_Definition:
Classification of the polygon features in a marsh unit as vegetated or unvegetated.
Attribute_Definition_Source: USGS
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: unvegetated
Enumerated_Domain_Value_Definition: Unvegetated part of the marsh unit.
Enumerated_Domain_Value_Definition_Source: USGS
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: vegetated
Enumerated_Domain_Value_Definition: Vegetated part of the marsh unit.
Enumerated_Domain_Value_Definition_Source: USGS
Attribute:
Attribute_Label: APGN_M2
Attribute_Definition:
Surface area of the selected polygon type (vegetated or unvegetated).
Attribute_Definition_Source: USGS
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 1.017241
Range_Domain_Maximum: 1189344.84656
Attribute_Units_of_Measure: square meters
Attribute:
Attribute_Label: ATOT_M2
Attribute_Definition: Total surface area of a marsh unit in square meters
Attribute_Definition_Source: USGS
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 8.876088
Range_Domain_Maximum: 1278469.79671
Attribute_Units_of_Measure: square 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: -11200
Range_Domain_Maximum: 0
Attribute_Units_of_Measure: None
Overview_Description:
Entity_and_Attribute_Overview:
In this dataset, the salt marsh complex in eastern Long Island has been delineated to conceptual salt marsh units to facilitate unit by unit evaluation of the response and resiliency of the marsh system to physical and biogeochemical drivers. Each unit is also analyzed based on the vegetated and unvegetated surface area coverage, the ratio of which can be an independent measure of marsh health for microtidal marshes on the Atlantic and Pacific coasts of the United States. 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 area values is assumed to be 1 meter.
Entity_and_Attribute_Detail_Citation: USGS
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:
CMU_ELI.shp (and files associated with a shapefile), browse graphic (CMU.png), and CSDGM metadata in XML format.
Distribution_Liability:
Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Not for navigational use.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: shapefile
Format_Version_Number: ArcGIS 10.7.1
Format_Information_Content:
This dataset contains a polygon shapefile and its components and metadata in xml format
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information: 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.
Digital_Form:
Digital_Transfer_Information:
Format_Name: WMS
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information: Access_Instructions:
The link in network resources points to the Web Mapping Services (WMS) end point.
Digital_Form:
Digital_Transfer_Information:
Format_Name: WFS
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information: Access_Instructions:
The link in network resources points to the Web Feature Service (WFS) end point.
Fees: None. No fees are applicable for obtaining the data set.
Metadata_Reference_Information:
Metadata_Date: 20200806
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: rwelk@usgs.gov
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/CMU_ELI.html>
Generated by mp version 2.9.50 on Tue Sep 21 18:18:59 2021