Metadata: Identification_Information: Citation: Citation_Information: Originator: Kate V. Ackerman Originator: Zafer Defne Originator: Neil K. Ganju Publication_Date: 20210518 Title: Unvegetated to vegetated ratio of marsh units in Blackwater salt marsh complex, Chesapeake Bay, Maryland Edition: 1.0 Geospatial_Data_Presentation_Form: Vector Digital dataset (Polygon) Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P9M7H6XG 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/P9M7H6XG Online_Linkage: https://www.sciencebase.gov/catalog/item/608aee71d34ef6cfc4aba948 Larger_Work_Citation: Citation_Information: Originator: Kate V. Ackerman Originator: Zafer Defne Originator: Neil K. Ganju Publication_Date: 2021 Title: Coastal wetlands of the Blackwater region, Chesapeake Bay, Maryland Edition: 1.0 Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P9M7H6XG 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., 2021, Coastal wetlands of the Blackwater region, Chesapeake Bay, Maryland: U.S. Geological Survey data release, https://doi.org/10.5066/P9M7H6XG. Online_Linkage: https://doi.org/10.5066/P9M7H6XG Online_Linkage: https://www.sciencebase.gov/catalog/item/605a4dbbd34e18948831d9b3 Description: Abstract: This data release contains coastal wetland synthesis products for the geographic region of Blackwater salt marsh complex, Chesapeake Bay, Maryland. Metrics for resiliency, including unvegetated to vegetated ratio (UVVR), marsh elevation, and others, 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: 2021 Currentness_Reference: publication date Status: Progress: Complete Maintenance_and_Update_Frequency: None Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -76.3333 East_Bounding_Coordinate: -75.6812 North_Bounding_Coordinate: 38.5053 South_Bounding_Coordinate: 38.2175 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: Theme_Keyword_Thesaurus: None Theme_Keyword: salt marsh Theme_Keyword: vegetation Theme_Keyword: marsh health Theme_Keyword: estuary Theme_Keyword: UVVR Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:608aee71d34ef6cfc4aba948 Place: Place_Keyword_Thesaurus: None Place_Keyword: Blackwater National Wildlife Refuge Place_Keyword: Honga River Place_Keyword: Fishing Bay Place_Keyword: Nanticoke River Place_Keyword: Dorchester County Place_Keyword: Wicomico County Place_Keyword: Chesapeake Bay Place_Keyword: Maryland Place_Keyword: United States 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: https://www.sciencebase.gov/catalog/file/get/608aee71d34ef6cfc4aba948/?name=UVVR_BW_Browse.png Browse_Graphic_File_Description: Graphic that shows UVVR of conceptual marsh units of the Blackwater region salt marsh complex. 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 unit boundaries and water and land boundaries inherit their accuracy from the source data, Blackwater region marsh units. Vegetated and unvegetated polygon accuracy is based on the 0.6-meter resolution National Agriculture Imagery Program (NAIP) products, and 1-meter resolution U.S. Geological Survey Coastal National Elevation Database (USGS CoNED) data. 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. This resulted in polygons that were removed from the dataset and FID CMU values that are not sequential. In two areas (around marsh unit 3094 and marsh unit 4424), there are marsh units that have straight lines for boundaries; this is due to larger areas of hydro-flattened bathymetry/elevation values that do not allow the basin analysis to identify ridge lines between basins. Most of these marsh units have a flag that shows that the hydro-flattened area of the marsh unit is greater than 25 percent of the marsh unit area. 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 results are specific to the marsh polygons as defined within the boundaries of the Blackwater region 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. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Horizontal accuracy is inherited from CoNED Digital Elevation Models. Vegetated and unvegetated polygons were based on the 0.6-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. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Danielson, J. Originator: Tyler, D. Publication_Date: 20160501 Title: Topobathymetric Model for Chesapeake Bay Region - District of Columbia, States of Delaware, Maryland, Pennsylvania, and Virginia, 1859 to 2015 Geospatial_Data_Presentation_Form: Raster Digital Dataset Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://topotools.cr.usgs.gov/topobathy_viewer/ Type_of_Source_Media: Digital Resources Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2016 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: CoNED Source_Contribution: Downloaded CoNED Digital Elevation Model geodatabase. Projection was NAD 1983 UTM Zone 18N with the North American Vertical Datum of 1988 (NAVD 88). Download date was 2020/01/29. Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey 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 Online_Linkage: https://earthexplorer.usgs.gov Type_of_Source_Media: Digital Resources Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2018 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: NAIP Source_Contribution: Downloaded NAIP 0.6-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: 2020 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 Online_Linkage: https://www.fws.gov/wetlands/data/Data-Download.html Type_of_Source_Media: Digital Resources Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2020 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: NWI Source_Contribution: Downloaded wetlands data for the state of Maryland in Shapefile format from the NWI download page. Projection was NAD 1983 Albers. Download date was 2020/01/02. Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2021 Title: Conceptual marsh units of Blackwater salt marsh complex, Chesapeake Bay, Maryland Geospatial_Data_Presentation_Form: Vector Digital Dataset (Polygon) Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://www.sciencebase.gov/catalog/item/608876f2d34e5611588fbcc6 Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2021 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: CMU_BW.shp Source_Contribution: Used conceptual marsh units to delineate marsh unit boundaries and areas of vegetation. Process_Step: Process_Description: This process step and all subsequent process steps were performed by the same person, Kate Ackerman, 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 (m^2) unless otherwise stated. a) Set the data frame coordinate system and projection to NAD 1983 UTM Zone 18N. b) Dissolve the vegetated and unvegetated classes in each marsh unit to have only one class for each marsh unit. DISSOLVE(Input features=[CMU_BW.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; Geographic transformation=WGS 1984 (ITRF00) to NAD 1983) the feature dataset to obtain dissolved marsh units [mu_diss.shp]. c) Create a rectangular polygon that covers the domain [extent.shp]. CLIP the CoNED elevation dataset by the boundaries polygon [elev_mosaic.tif]. Source_Used_Citation_Abbreviation: CoNED Source_Used_Citation_Abbreviation: CMU_BW.shp Process_Date: 2020 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: Prepare a 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.shp]. At the end of the analysis the results are clipped to the boundaries of the salt marsh area [MU_mask.shp]. Both [UVVR_mask.shp] and [MU_mask.shp] are edited to determine which interior polygons are removed. a) EXPORT features from NWI 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]. b) 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]. 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. 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_voids_single.shp]. e) 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. f) ERASE [erase_inside.shp] from [MU_mask01.shp] to obtain [MU_mask.shp], and ERASE [erase_inside.shp] from [UVVR_mask01.shp] after BUFFER [erase_inside.shp] by -5 meters, to obtain [UVVR_mask.shp]. Source_Used_Citation_Abbreviation: NWI Process_Date: 2020 Source_Produced_Citation_Abbreviation: MU_mask.shp Source_Produced_Citation_Abbreviation: UVVR_mask.shp Process_Step: Process_Description: Compute vegetated and unvegetated boundaries by image processing. a) EXTRACT BY MASK from elevation raster [elev_mosaic.tif] and the NAIP imagery 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 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]. 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 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. c) RASTER TO POLYGON(Simplify polygons=False) and CLIP with the final marsh complex outline [mu_diss.shp] to obtain [UVVc_filt_clip.shp]. d) 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]. e) INTERSECT the final conceptual marsh units [CMU.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]. 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. Visually inspect and manually remove marsh units that are fully forested due to polygon artifacts that are a result of buffering. 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) DISSOLVE(Input features=[UVV_poly_diss.shp]; Dissolve fields=FID_CMU, gridcode; Statistics field=UVVR, ATOT_M2 and FLG with Statistics type= First for all) to obtain [mu_UVVR_BW.shp]. h) Add field "FLG" to flag anomalous marsh units based on absence of vegetation, elevation and surface area. 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 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; 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. i) SELECT BY ATTRIBUTES FROM [CMU_BW.shp] where "TYP"= 'vegetated,' and join field "APGN_M2" from [CMU_BW.shp] on the feature dataset [mu_UVVR_BW.shp] and rename this field "AVEG_M2." j) 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 UVVR for each marsh unit [mu_UVVR_BW.shp]. Source_Used_Citation_Abbreviation: elev_mosaic.tif Source_Used_Citation_Abbreviation: NAIP Process_Date: 2020 Source_Produced_Citation_Abbreviation: mu_UVVR_BW.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: 8518 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_BW 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: 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: 8532 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: 142.611297122 Range_Domain_Maximum: 3039925.37708 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: 2284096.35511 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: 1401.50022619 Attribute_Units_of_Measure: none Attribute: Attribute_Label: FLG Attribute_Definition: Marsh unit flag indicating anomalous marsh units based on absence of vegetation, elevation and surface area. 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 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; 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: -1201 Range_Domain_Maximum: 0 Attribute_Units_of_Measure: none Overview_Description: Entity_and_Attribute_Overview: In this dataset, the salt marsh complex in the Blackwater region has 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 microtidal 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_UVRR_BW.shp (and files associated with a shapefile), browse graphic (UVVR_BW_Browse.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: Network_Address: Network_Resource_Name: https://www.sciencebase.gov/catalog/file/get/608aee71d34ef6cfc4aba948 Network_Resource_Name: https://www.sciencebase.gov/catalog/item/608aee71d34ef6cfc4aba948 Network_Resource_Name: https://doi.org/10.5066/P9M7H6XG 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: Network_Address: Network_Resource_Name: https://www.sciencebase.gov/catalogMaps/mapping/ows/608aee71d34ef6cfc4aba948?service=wms&request=getcapabilities&version=1.3.0 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: Network_Address: Network_Resource_Name: https://www.sciencebase.gov/catalogMaps/mapping/ows/608aee71d34ef6cfc4aba948?service=wfs&request=getcapabilities&version=1.0.0 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: 20210608 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: kackerman@usgs.gov Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998