Unvegetated to vegetated ratio of marsh units in Eastern Shore of Virginia salt marshes

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Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: Kate V. Ackerman
Originator: Zafer Defne
Originator: Neil K. Ganju
Publication_Date: 20230328
Title:
Unvegetated to vegetated ratio of marsh units in Eastern Shore of Virginia salt marshes
Edition: 1.0
Geospatial_Data_Presentation_Form: vector digital dataset (polygon)
Series_Information:
Series_Name: data release
Issue_Identification: DOI:10.5066/P9E6V0QK
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/P9E6V0QK
Online_Linkage: Larger_Work_Citation:
Citation_Information:
Originator: Kate V. Ackerman
Originator: Zafer Defne
Originator: Neil K. Ganju
Publication_Date: 2023
Title:
Geospatial characterization of salt marshes on the Eastern Shore of Virginia
Edition: 1.0
Geospatial_Data_Presentation_Form: vector digital data
Series_Information:
Series_Name: data release
Issue_Identification: DOI:10.5066/P9E6V0QK
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Other_Citation_Details:
Suggested citation: Ackerman, K.V., Defne, Z., and Ganju, N.K., 2023, Geospatial characterization of salt marshes on the Eastern Shore of Virginia: U.S. Geological Survey data release, https://doi.org/10.5066/P9E6V0QK.
Online_Linkage: https://doi.org/10.5066/P9E6V0QK
Online_Linkage:
Description:
Abstract:
This data release contains coastal wetland synthesis products for the Atlantic-facing Eastern Shore of Virginia (the data release for the Chesapeake Bay-facing portion of the Eastern Shore of Virginia is found here: https://doi.org/10.5066/P997EJYB). Metrics for resiliency, including unvegetated to vegetated ratio (UVVR), marsh elevation, and tidal range are calculated for smaller units delineated from a digital elevation model, providing the spatial variability of physical factors that influence wetland health. 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:
The purpose of this shapefile is to calculate the ratio of unvegetated area to vegetated area (UVVR) in each marsh unit. Analysis of unvegetated to vegetated marsh ratio is part of a comprehensive assessment to identify the factors and their weights in determining the vulnerability and resiliency of salt marshes. An unvegetated area to vegetated area ratio was defined as a potential indicator of the current state of a salt marsh unit. UVVR was calculated based on U.S. Department of Agriculture National Agriculture Imagery Program (NAIP) 0.6-meter resolution imagery.
Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2023
Currentness_Reference: publication date
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -75.977747
East_Bounding_Coordinate: -75.474028
North_Bounding_Coordinate: 37.881830
South_Bounding_Coordinate: 37.085411
Keywords:
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: oceans
Theme_Keyword: inlandWaters
Theme_Keyword: environment
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: vegetation
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: salt marsh
Theme_Keyword: marsh health
Theme_Keyword: estuary
Theme_Keyword: UVVR
Theme:
Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: USGS:63e53aced34efa0476ade04c
Place:
Place_Keyword_Thesaurus: None
Place_Keyword: United States
Place_Keyword: Atlantic Ocean
Place_Keyword: Virginia
Place_Keyword: Wallops Island
Place_Keyword: Chincoteague National Wildlife Refuge
Place_Keyword: Metompkin Island
Place_Keyword: Cedar Island
Place_Keyword: Parramore Island
Place_Keyword: Hog Island
Place_Keyword: Mockhorn Island
Place_Keyword: Smith Island
Place_Keyword: Fisherman Island National Wildlife Refuge
Place_Keyword: Eastern Shore National Wildlife Refuge
Place_Keyword: Virginia Coast Reserve
Access_Constraints: None
Use_Constraints:
The unvegetated to vegetated ratio for each marsh unit is 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_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
Browse_Graphic:
Browse_Graphic_File_Name: Browse_Graphic_File_Description:
Graphic that shows UVVR of conceptual marsh units in Eastern Shore of Virginia salt marshes.
Browse_Graphic_File_Type: PNG
Native_Data_Set_Environment:
Environment as of Metadata Creation: Microsoft Windows 10; Esri ArcGIS Pro (version 2.8.8)
Cross_Reference:
Citation_Information:
Originator: N.K. Ganju
Originator: Z. Defne
Originator: S. Fagherazzi
Publication_Date: 2020
Title:
Are elevation and open-water conversion of salt marshes connected?
Geospatial_Data_Presentation_Form: publication
Series_Information:
Series_Name: Geophysical Research Letters
Issue_Identification: v. 47, issue 3
Other_Citation_Details:
For more information about the UVVR, please see this publication.
Online_Linkage: https://doi.org/10.1029/2019GL086703
Cross_Reference:
Citation_Information:
Originator: Z. Defne
Originator: A.L. Aretxabaleta
Originator: N.K. Ganju
Originator: T.S. Kalra
Originator: D.K. Jones
Originator: K.E.L. Smith
Publication_Date: 2020
Title:
A geospatially resolved wetland vulnerability index: Synthesis of physical drivers
Geospatial_Data_Presentation_Form: publication
Series_Information:
Series_Name: PLOS ONE
Issue_Identification: none
Other_Citation_Details:
For more information about the UVVR, please see this publication.
Online_Linkage: https://doi.org/10.1371/journal.pone.0228504
Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
Marsh unit boundaries and water and land boundaries inherit their accuracy from the source data, the conceptual marsh units. Vegetated and unvegetated polygon accuracy is based on the 0.6-meter resolution National Agriculture Imagery Program (NAIP) products, and the elevation dataset (2015 USGS Lidar DEM).
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 m^2) were assumed to be marginal and were assigned the classification from the surrounding majority value.
A visual comparison between NAIP imagery was performed at randomly selected sites to verify the land and water boundaries. Marsh polygons without any vegetation were assigned a UVVR value of -1.
Completeness_Report:
The marsh polygons are bound to the borders of the Eastern Shore of Virginia's 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 narrower than 10 meters. Occasionally, marsh units are retained in this dataset even though the imagery displayed extreme change (e.g., partially or completely converted to water) from the NWI wetland delineation (e.g., marsh units 638, 796, 1366). In a few areas, there are no marsh units where there is visible marsh plain (e.g., west of marsh units 4583 and 4566; west of 5878; south of 5910; west of 5855), because the areas are classified in the NWI as estuarine intertidal unconsolidated shore, which is not included in our salt marsh boundaries. In a few locations, there may be areas that that are classified as unvegetated but are in fact very sparsely vegetated. 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 for the polygon boundaries is inherited from the source layer, the conceptual marsh units, and is considered to be +/- 6 meters.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: 2018
Title: 2015 USGS Lidar DEM: Eastern Shore VA
Edition: First
Geospatial_Data_Presentation_Form: raster digital dataset
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Other_Citation_Details:
Downloaded 1-meter 2015 USGS Lidar DEM. Projection was NAD 1983 UTM Zone 18N with the North American Vertical Datum of 1988 (NAVD 88). Download date was 04/13/2021.
Online_Linkage: https://www.fisheries.noaa.gov/inport/item/51444
Type_of_Source_Media: Digital
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20150411
Ending_Date: 20150424
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: USGS DEM
Source_Contribution: Elevation dataset
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Department of Agriculture
Publication_Date: 2018
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
Other_Citation_Details:
Downloaded NAIP 4-band, 0.6-meter resolution imagery from the USGS Earth Explorer. Projection was NAD 1983 UTM Zone 18N. Download date was 01/17/2020.
Online_Linkage: https://earthexplorer.usgs.gov
Type_of_Source_Media: Digital
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2018
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: NAIP
Source_Contribution: Aerial imagery dataset
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Fish and Wildlife Service
Publication_Date: 20191001
Title: National Wetland Inventory
Geospatial_Data_Presentation_Form: vector digital dataset (polygon)
Publication_Information:
Publication_Place: Madison, WI
Publisher: U.S. Fish and Wildlife Service
Other_Citation_Details:
Downloaded wetlands data for Virginia in shapefile format from the NWI download page. Projection was NAD 1983 Albers. Download date was 01/02/2020.
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: 2019
Source_Currentness_Reference: publication date
Source_Citation_Abbreviation: NWI
Source_Contribution: Wetlands dataset
Source_Information:
Source_Citation:
Citation_Information:
Originator: Ackerman, K.V., Defne, Z., and Ganju, N.K.
Publication_Date: 2023
Title:
Conceptual marsh units of salt marshes on the Eastern Shore of Virginia
Geospatial_Data_Presentation_Form: vector digital dataset (polygon)
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Online_Linkage:
Type_of_Source_Media: Digital
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2023
Source_Currentness_Reference: publication date
Source_Citation_Abbreviation: CMU_ESV
Source_Contribution:
Used conceptual marsh units, generated as part of this data release, to delineate marsh unit boundaries.
Process_Step:
Process_Description:
This process step and all subsequent process steps were performed by the same person, Kate Ackerman, in ArcGIS Pro (ver. 2.8.8), unless otherwise stated. For simple operations the name of the geoprocessing tool used is given in capital letters; for complex operations, the name of geoprocessing tool used is given in capital letters and 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 (m^2) unless otherwise stated.
a) Set the data frame coordinate system and projection to NAD 1983 UTM Zone 18N.
b) Establish marsh unit boundaries. Dissolve the vegetated and unvegetated classes in each marsh unit to have only one class for each marsh unit. DISSOLVE(Input features=[CMU_ESV.shp]; Dissolve field=FID_CMU; Statistics field=ATOT_M2 and FLG with Statistics type= First). PROJECT(Input coordinate system=WGS 1984 Web Mercator Auxiliary Sphere; Output coordinate system=NAD 1983 UTM Zone 18N) the feature dataset to obtain dissolved marsh units [mu_diss.shp].
c) Prepare elevation dataset. Combine all downloaded tiles into one raster, using MOSAIC TO NEW RASTER, and PROJECT RASTER to NAD 1983 UTM Zone 18N.
d) Create a polygon that covers the area of interest [extent.shp]. CLIP the mosaicked elevation dataset created in step (c) by [extent.shp] to create [elev_mosaic.tif].
Source_Used_Citation_Abbreviation: USGS DEM
Process_Date: 2022
Source_Produced_Citation_Abbreviation: elev_mosaic.tif
Source_Produced_Citation_Abbreviation: mu_diss.shp
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:
This process step creates two mask polygons to define analysis boundaries over the area of interest. 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 created [UVVR_mask.shp]. This larger mask area is clipped to the boundaries of the salt marsh area to create [MU_mask.shp]. This process step explains how [UVVR_mask.shp] and [MU_mask.shp] are created and edited to determine which interior polygons are removed.
a) Create a shapefile of the salt marshes as defined by NWI. EXPORT features (use the same coordinate system as the data frame) from NWI dataset of all wetlands for the area (referred to here as [NWI_entire.shp]) 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 to create [NWI_exclusive_select.shp].
b) Create the preliminary masks that will be edited in the subsequent steps to make the final masks. BUFFER salt marsh classes (Input features=[NWI_exclusive_select.shp]; Linear unit=5 meters; Dissolve type=All) to obtain the mask polygon [buff5m.shp] and ELIMINATE POLYGON PART (Input features= [buff5m.shp]; Condition=Percentage; Percentage=99; Eliminate contained part only) to remove small interior polygons to obtain [UVVR_mask01.shp]. Apply BUFFER (Input features=[UVVR_mask01.shp]; Linear unit= -5 meters; Dissolve type= All) to obtain [MU_mask01.shp].
c) 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 [NWI_inclusive_select.shp]. MULTIPART TO SINGLEPART to separate individual polygons [NWI_inclusive_single.shp].
d) To exclude the voids in the NWI map during the analysis, these interior polygons need to be removed from the mask. ERASE [NWI_exclusive_select.shp] from [extent.shp] and MULTIPART TO SINGLEPART to get [NWI_exc_voids_single.shp].
To create the final mask shapefiles ([MU_mask.shp] and [UVVR_mask.shp]), areas that should not be included are removed (e.g., forest areas), and areas that should be included are incorporated (estuarine and marine wetland systems that are completely surrounded by salt marsh (e.g., interior ponds)):
e)SELECT BY LOCATION from [NWI_inclusive_single.shp] that are completely within the [MU_mask01.shp] and SELECT BY LOCATION from [NWI_exc_voids_single.shp] that are completely within the [MU_mask01.shp]. UNION all feature sets to get polygons to be excluded [erase_inside.shp] from the final masks.
f) Spatially join the [NWI_entire.shp] to [erase_inside.shp] in order to assign wetland attributes to the [erase_inside.shp] polygons. SPATIAL JOIN (target features= [erase_inside.shp]; join features= [NWI_entire.shp]; output feature class= [erase_inside_NWI_info.shp]; join operation= one to one; keep all target features; match option= intersect; search radius= -1 m).
g) Select the polygons that are marine or non-forested estuarine wetlands from [erase_inside_NWI_info.shp]: SELECT (ATTRIBUTE LIKE 'E1%' OR ATTRIBUTE LIKE 'E2AB%' OR ATTRIBUTE LIKE 'E2RF%' OR ATTRIBUTE LIKE 'E2SB%' OR ATTRIBUTE LIKE 'E2RS%' OR ATTRIBUTE LIKE 'E2US%' OR ATTRIBUTE LIKE 'E2EM%' OR ATTRIBUTE LIKE ‘E2SS%’ OR ATTRIBUTE LIKE ‘M1%’ OR ATTRIBUTE LIKE ‘M2%) to select all marine systems, estuarine subtidal systems, estuarine intertidal areas of aquatic bed, reef, streambed, rocky shore, unconsolidated shore, emergent or scrub-shrub [erase_inside_keepIntPonds.shp].
h) Remove the polygons from [erase_inside_NWI_info.shp] that should be retained (these are the interior ponds): ERASE (input feature= [erase_inside_NWI_info.shp]; erase feature= [erase_inside_keepIntPonds.shp]; output feature= [erase_inside_final.shp]).
i) If any additional polygons need to be removed from the mask, include them in a new feature layer [erase_mask_manual.shp] and MERGE with [erase_inside_final.shp].
j) Remove any unwanted polygons from the original [MU_mask01.shp] to make the final [MU_Mask.shp]: ERASE (input feature= [MU_mask01.shp]; erase feature= [erase_inside_final.shp]; output feature= [MU_mask.shp]).
k) BUFFER [MU_mask.shp] by 5m (side type= full; end type= round; method: geodesic; dissolve type: single feature) to obtain [UVVR_mask.shp].
Source_Used_Citation_Abbreviation: NWI
Process_Date: 2022
Source_Produced_Citation_Abbreviation: MU_mask.shp
Source_Produced_Citation_Abbreviation: UVVR_mask.shp
Process_Step:
Process_Description:
Compute vegetated and unvegetated areas by image processing.
a) MOSAIC TO NEW RASTER the NAIP tiles.
b) EXTRACT BY MASK from the elevation raster [elev_mosaic.tif] and the NAIP imagery raster using [UVVR_mask.shp] polygon and append “UVVR_mask” to the file name. Rescale the elevation raster values to the same range with 8-bit NAIP imagery (0 to 255) using min-max scaling in RASTER CALCULATOR (map algebra expression: (("elev_mosaic_UVVR_mask.tif"-(min value of the input raster))*(255-0)/(max value of the input raster)-( min value of the input raster)))+0). Perform ISO CLUSTER UNSUPERVISED CLASSIFICATION with 5 input bands: the 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]. In some regions, a couple of the 32 classes are classified as vegetated in one area but unvegetated in another area. For these classes, the area can be split into separate sections to allow one section to be classified as vegetated and the other as unvegetated.
c) 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 GROUP(Number of neighbors=4; Zone grouping method=Within; Add Link field to output) to get the [UVV_region.tif], and TEST("Count" < 9) to set a threshold value of 9 raster cells [lt9.tif]. Use RASTER CALCULATOR to toggle the value of the Link field in the region raster [Map algebra expression=Con("%lt9.tif%", ~Lookup("%UVVc_region.tif%","LINK"),Lookup("%UVVc_region.tif%","LINK"))], where the test raster indicates regions with areas smaller than the threshold.
d) RASTER TO POLYGON(Simplify polygons=False) and CLIP with the final marsh complex outline [mu_diss.shp] to obtain [UVVc_filt_clip.shp].
e) REPAIR GEOMETRY, ADD GEOMETRY ATTRIBUTES(Geometry properties=Area_geodesic; Area unit=Square_meters), CALCULATE FIELD(Python_9.3 expression; Field name=gridcode, Expression=filt(!gridcode!, !AREA_GEO!), Code Block= def filt(gridcode, AREA_GEO):/if gridcode== 0 and AREA_GEO < 9:/return 1/else:/return gridcode) and DISSOLVE(Create multipart features=False) to get filtered, clipped and dissolved unvegetated-vegetated polygons [UVVc_filt_clip_diss.shp].
f) INTERSECT the final conceptual marsh units [mu_diss.shp] with unvegetated-vegetated polygons [UVVc_filt_clip_diss.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) and REPAIR GEOMETRY to get [UVV_poly_diss.shp]. Add fields "TYP", "APGN_M2", and "ATOT_M2" for type of polygon indicating vegetated or unvegetated, surface area of the polygon, and total surface area of the marsh unit, respectively, and calculate "APGN_M2" and "ATOT_M2" areas.
g) Visually inspect and manually remove marsh units that are fully forested due to polygon artifacts that are a result of buffering. Remove marsh units that are completely unvegetated, unattached to other marsh units (i.e., islands) and less than 25,000 m2, as these are artifacts of the NWI dataset. Remove marsh units that are linear features (edges parallel to each other) and unattached to other marsh units (i.e., islands), as these are artifacts of the NWI dataset.
h) 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.
i) DISSOLVE(Input features=[UVV_poly_diss.shp]; Dissolve fields=FID_CMU; Statistics field=UVVR, ATOT_M2 and FLG with Statistics type= First for all) to obtain [mu_UVVR_ESV.shp].
j) SELECT BY ATTRIBUTES FROM [CMU_ESV.shp] where "TYP"= 'vegetated,' and join field "APGN_M2" from [CMU_ESV.shp] to [mu_UVVR_ESV.shp] and rename this field "AVEG_M2."
k) Add field "FLG" to flag anomalous marsh units based on absence of vegetation, elevation, surface area, and tidal range extrapolation. The flags are calculated in their respective shapefile (i.e., elevation flags are calculated in the elevation shapefile). Set FLG to (-1) no vegetated area in the marsh unit; (-10) marsh unit elevation higher than the 99.8 percentile; (-100) marsh unit elevation less than the 0.2 percentile; (-200) greater than 25 percent of the marsh unit elevation is hydro-flattened; (-1000) marsh unit surface area less than 900 m^2; (-10000) mean tidal range of marsh unit is extrapolated; and (0) no flag. Combination of negative values indicates a combination of flags; for example, -1001 indicates no vegetated area and area less than 900 m^2.
l) Rearrange field names and change the projection for better performance of web services with online base maps. PROJECT(Output coordinate system=WGS 1984 Web Mercator Auxiliary Sphere) the feature dataset to obtain the UVVR for each marsh unit [mu_UVVR_ESV.shp].
Source_Used_Citation_Abbreviation: elev_mosaic.tif
Source_Used_Citation_Abbreviation: NAIP
Process_Date: 2022
Source_Produced_Citation_Abbreviation: mu_UVVR_ESV.shp
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: 6358
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)
Map_Projection_Parameters:
False_Easting: 0.0
False_Northing: 0.0
Longitude_of_Central_Meridian: 0.0
Standard_Parallel: 0.0
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:
Abscissa_Resolution: 0.6096
Ordinate_Resolution: 0.6096
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: D_WGS_1984
Ellipsoid_Name: WGS 84
Semi-major_Axis: 6378137.0
Denominator_of_Flattening_Ratio: 298.257223563
Entity_and_Attribute_Information:
Detailed_Description:
Entity_Type:
Entity_Type_Label: mu_UVVR_ESV.shp attribute table
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: FID_CMU
Attribute_Definition:
Unique whole numbers used to identify each conceptual marsh unit.
Attribute_Definition_Source: USGS
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 0
Range_Domain_Maximum: 6358
Attribute:
Attribute_Label: ATOT_M2
Attribute_Definition: Total surface area of a marsh unit.
Attribute_Definition_Source: USGS
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 123.826608084
Range_Domain_Maximum: 1906442.13071
Attribute_Units_of_Measure: m^2
Attribute:
Attribute_Label: AVEG_M2
Attribute_Definition: Surface area of the vegetated part of a marsh unit.
Attribute_Definition_Source: USGS
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 1628088.8009
Attribute_Units_of_Measure: m^2
Attribute:
Attribute_Label: UVVR
Attribute_Definition:
Ratio of unvegetated surface area to vegetated surface area. Ordinarily, UVVR ranges from zero (completely vegetated) to infinity (completely unvegetated). However, it is assigned the value of -1 when completely unvegetated.
Attribute_Definition_Source: USGS
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -1.0
Range_Domain_Maximum: 1155922.80899
Attribute_Units_of_Measure: none
Attribute:
Attribute_Label: FLG
Attribute_Definition:
Marsh unit flag indicating anomalous marsh units based on absence of vegetation, elevation, surface area and tidal range extrapolation. FLG values indicate: (-1) no vegetated area in the marsh unit; (-10) marsh unit elevation higher than the 99.8 percentile; (-100) marsh unit elevation less than the 0.2 percentile; (-200) greater than 25 percent of the marsh unit elevation is hydro-flattened; (-1000) marsh unit surface area less than 900 m^2; (-10000) mean tidal range of marsh unit is extrapolated; and (0) no flag. Combination of negative values indicates a combination of flags. For example, -1001 indicates no vegetated area and area less than 900 m^2.
Attribute_Definition_Source: USGS
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -11100
Range_Domain_Maximum: 0
Attribute_Units_of_Measure: none
Overview_Description:
Entity_and_Attribute_Overview:
In this dataset, the salt marshes of the Eastern Shore of Virginia have been delineated to conceptual salt marsh units to facilitate unit by unit evaluation of 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 salt marshes on the Atlantic and Pacific coasts of the United States. UVVR is calculated as the ratio of unvegetated area to vegetated area in a marsh unit. 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 and UVVR is assumed to be 1 meter and 0.001, respectively.
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:
mu_UVVR_ESV.zip (ZIP file contains the shapefile mu_UVVR_ESV.shp and the additional shapefile components), a browse graphic (UVVR_ESV_Browse.png) and FGDC CSDGM metadata in xml format.
Distribution_Liability:
Although these data have been processed successfully on a computer system at 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. 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. Any use of trade, firm, or product 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 Pro 2.8.8
Format_Information_Content:
This dataset contains a polygon shapefile and its components and metadata in xml format.
Transfer_Size: 30
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 dataset.
Metadata_Reference_Information:
Metadata_Date: 20230328
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Kate V. Ackerman
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing address
Address: 384 Woods Hole Rd
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: 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: 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_P9E6V0QK/mu_UVVR_ESV.html>
Generated by mp version 2.9.51 on Wed Mar 29 13:42:27 2023