Metadata: Identification_Information: Citation: Citation_Information: Originator: Kate V. Ackerman Originator: Zafer Defne Originator: Neil K. Ganju Publication_Date: 20240129 Title: Elevation of marsh units in Maine salt marshes Edition: 1.0 Geospatial_Data_Presentation_Form: vector digital dataset (polygon) Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P9FRGLB0 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/P9FRGLB0 Online_Linkage: https://www.sciencebase.gov/catalog/item/657b3ee2d34e952b2274bb36 Larger_Work_Citation: Citation_Information: Originator: Kate V. Ackerman Originator: Zafer Defne Originator: Neil K. Ganju Publication_Date: 2024 Title: Geospatial characterization of salt marshes in Maine Edition: 1.0 Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P9FRGLB0 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., 2024, Geospatial characterization of salt marshes in Maine: U.S. Geological Survey data release, https://doi.org/10.5066/P9FRGLB0. Online_Linkage: https://doi.org/10.5066/P9FRGLB0 Online_Linkage: https://www.sciencebase.gov/catalog/item/657b3ac7d34e952b2274ba98 Description: Abstract: This data release contains coastal wetland synthesis products for the state of Maine. Metrics for resiliency, including the unvegetated to vegetated ratio (UVVR), marsh elevation, tidal range, and lifespan, 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 mean elevation for each marsh unit and its vegetated component. Analysis of marsh elevation is part of a comprehensive assessment to identify the factors and their weights in determining the vulnerability and resiliency of salt marshes. Elevation distribution in Maine salt marshes is given in terms of mean elevation of conceptual marsh units, as well as the vegetated portion of the marsh unit. The elevation data is based on the 1-meter ME DEM. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2024 Currentness_Reference: publication date Status: Progress: Complete Maintenance_and_Update_Frequency: None Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -70.828578 East_Bounding_Coordinate: -66.984779 North_Bounding_Coordinate: 45.096044 South_Bounding_Coordinate: 43.069179 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: oceans Theme_Keyword: inlandWaters Theme_Keyword: environment Theme_Keyword: elevation 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: elevation Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:657b3ee2d34e952b2274bb36 Place: Place_Keyword_Thesaurus: None Place_Keyword: United States Place_Keyword: Maine Place_Keyword: Acadia National Park Access_Constraints: None Use_Constraints: The mean elevation 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/657b3ee2d34e952b2274bb36/?name=Elev_ME_Browse.png&allowOpen=true Browse_Graphic_File_Description: Graphic that shows elevation of conceptual marsh units in Maine 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) Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Marsh units and water and land boundaries inherit their horizontal accuracy from the accuracy of the source data, the conceptual marsh units, and their vertical accuracy from the elevation dataset (1-meter ME DEM). Logical_Consistency_Report: Positive elevation indicates above sea level. Marsh units with extremely low elevation (smaller than the 0.2 percentile value), extremely high elevation (larger than the 99.8 percentile value) or areas less than 900 square meters were flagged in the dataset. Completeness_Report: The marsh polygons are bound to the borders of Maine'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 2345, 3745). In a few areas, there are no marsh units where there is visible marsh plain (e.g., northwest of marsh unit 1824), because the areas are classified in the NWI as estuarine subtidal unconsolidated shore, which is not included as salt marsh in this analysis. 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. 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 dataset (1-meter ME DEM). The vertical accuracy is inherited from the source elevation dataset; it is reported to be 0.98 meters. No additional accuracy assessment of the vertical accuracy has been conducted. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2023 Title: 3D Elevation Program (3DEP) Edition: First Geospatial_Data_Presentation_Form: raster digital dataset Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: These data were published on multiple dates between March 2020 and March 2023. Downloaded 1-meter DEM. Projection was NAD 1983 UTM Zone 19N referenced to the North American Vertical Datum of 1988 (NAVD88). Multiple download dates between 2/28/2023 and 9/12/2023. Online_Linkage: https://apps.nationalmap.gov/downloader/ Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20190101 Ending_Date: 20211231 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: ME DEM Source_Contribution: Elevation dataset Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2011 Title: National Elevation Dataset (NED) Edition: First Geospatial_Data_Presentation_Form: raster digital dataset Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: Downloaded 1/9 arc-second DEM for a few very small areas not covered by the 1-meter DEM. The data is distributed in geographic coordinates (NAD83), referenced to the North American Vertical Datum of 1988 (NAVD88). Download date was 9/12/2023. Online_Linkage: https://apps.nationalmap.gov/downloader/ Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20101024 Ending_Date: 20101201 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: ME DEM 2 Source_Contribution: Elevation dataset Source_Information: Source_Citation: Citation_Information: Originator: K.V. Ackerman Originator: Z. Defne Originator: N.K. Ganju Publication_Date: 2024 Title: Conceptual marsh units of Maine salt marshes, in Geospatial characterization of salt marshes in Maine Edition: 1.0 Geospatial_Data_Presentation_Form: vector digital dataset (polygon) Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P9FRGLB0 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: This dataset (Conceptual marsh units of Maine salt marshes) is within the larger data release (Geospatial characterization of salt marshes in Maine). The first link below is to the conceptual marsh units data and the second link is to the data release. Online_Linkage: https://www.sciencebase.gov/catalog/item/657b3ea5d34e952b2274bb2f Online_Linkage: https://doi.org/10.5066/P9FRGLB0 Type_of_Source_Media: Digital Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2024 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: CMU_ME Source_Contribution: Used conceptual marsh units, generated as part of this data release, 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 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 the 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 unless otherwise stated. a) Set the data frame coordinate system and projection to NAD 1983 UTM Zone 19N. 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_ME.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 19N) 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 19N. 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: ME DEM Source_Used_Citation_Abbreviation: ME DEM 2 Source_Used_Citation_Abbreviation: CMU_ME Process_Date: 2023 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: a) Remove pixels from elevation raster that are hydro-flattened. Use FOCAL STATISTICS (Input raster=[elev_mosaic.tif], Output raster=[FocalStats_3x3_range.tif], Neighborhood settings=3x3 cell, Statistics type=range) and RASTER CALCULATOR to identify (Map algebra expression: Con("%FocalStats_3x3_range.tif%" == 0,-1,1); Output raster=[elev_mosaic_One_NegOne.tif]) and remove (Map algebra expression: SetNull("%elev_mosaic_One_NegOne.tif%", "%elev_mosaic.tif%", "value = -1"); Output raster=[elev_mosaic_noHF.tif]) all hydro-flattened areas from [elev_mosaic.tif] to create [elev_mosaic_noHF.tif]. b) Calculate the mean elevation for each marsh unit with ZONAL STATISTICS AS TABLE (Feature zone data=[mu_diss.shp], Zone field=FID_CMU; Input value raster=[elev_mosaic_noHF.tif]; Statistics type=Mean; Output table=[mu]; Ignore Nodata=True). JOIN mean elevation from [mu] table to marsh units layer [mu_diss.shp] based on the "FID_CMU" field. Export dataset as a shapefile [mu_elev.shp]. Rename "mu_MEAN" to "MU_ELEV." c) Calculate the percent of the marsh unit that has hydro-flattened area. ZONAL STATISTICS AS TABLE (Feature zone data=[mu_elev.shp], Zone field=FID_CMU; Input value raster=[elev_mosaic_One_NegOne.tif]; Statistics type=Mean; Output table=[zs_muelev_HF]; Ignore Nodata=True). ADD FIELD to the output table to calculate hydro-flattened area of each marsh unit (MU_HFAR), CALCULATE FIELD (MU_HFAR= (1-MEAN)/2). JOIN MU_HFAR field to [mu_elev.shp]. If the percent hydro-flattened area is greater than 25 percent, set the marsh unit elevation to -9999. d) Calculate the elevation of the vegetated area of the marsh unit. SELECT BY ATTRIBUTES from [CMU_ME.shp] where "TYP"= 'vegetated', output: [CMU_ME_VEG.shp]. ZONAL STATISTICS AS TABLE (Feature zone data=[CMU_ME_VEG.shp], Zone field=FID_CMU; Input value raster=[elev_mosaic_noHF.tif]; Statistics type=Mean; Output table=[vg]; Ignore Nodata=True). Join the mean elevation of the vegetated portion to [mu_elev.shp] and rename the field to "VG_ELEV." e) Calculate the percent of the vegetated portion of the marsh unit that has hydro-flattened area. ZONAL STATISTICS AS TABLE (Feature zone data=[CMU_ME_VEG.shp], Zone field=FID_CMU; Input value raster=[elev_mosaic_One_NegOne.tif]; Statistics type=Mean; Output table=[zs_muelev_HF]; Ignore Nodata=True). ADD FIELD (VG_HFAR) to output table, CALCULATE FIELD (VG_HFAR= (1-MEAN)/2). Join VG_HFAR field to [mu_elev.shp]. If the percent hydro-flattened area is greater than 25 percent, set the vegetated elevation to -9999. f) JOIN the vegetated area (AVEG_M2) from [CMU_ME_VEG.shp] to [mu_elev.shp]. Source_Used_Citation_Abbreviation: elev_mosaic.tif Process_Date: 2023 Source_Produced_Citation_Abbreviation: mu_elev.shp Process_Step: Process_Description: a) Run Python script (marsv5.py) in ArcGIS Pro (v.2.8.8) to calculate metrics that quantify the distribution of marsh unit elevation values. Skewness ("SKWNSS") is the measure of asymmetry of the elevation distribution in the vegetated part of a marsh unit. Positive skewness values, i.e. right-skewed distributions, indicate clustering of elevation distributions towards lower elevations. Negative skewness values indicate a left-skewed distribution and clustering towards higher elevations. Lower third ("LOW3RD") is the percent of elevation values that fall within the lowest third of the elevation range within the vegetated part of a marsh unit. SKWNSS and LOW3RD parameters are calculated by applying the formulation of Raposa et al. (2016) to the elevation raster within the vegetated part of each marsh unit. JOIN these values to [mu_elev.shp]. If VG_ELEV= -9999, set SKWNESS and LOW3RD values to -9999. Export to a new shapefile [mu_elev_ME.shp]. Reference: Raposa, K. B., Wasson, K., Smith, E., Crooks, J. A., Delgado, P., Fernald, S. H., et al. (2016). Assessing tidal marsh resilience to sea-level rise at broad geographic scales with multi-metric indices. Biological Conservation, 204, 263–275. https://doi.org/10.1016/J.BIOCON.2016.10.015. Source_Used_Citation_Abbreviation: mu_elev.shp Process_Date: 2023 Source_Produced_Citation_Abbreviation: mu_elev_ME.shp Process_Step: Process_Description: a) 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 square meters; (-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 square meters. b) Rearrange fields 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 final elevation dataset [mu_elev_ME.shp]. Process_Date: 2023 Source_Produced_Citation_Abbreviation: mu_elev_ME.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: 4627 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_elev_ME.shp 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: Feature geometry. Marsh units are polygon 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: 4626 Attribute_Units_of_Measure: none 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: 109.38286 Range_Domain_Maximum: 1374107.55372 Attribute_Units_of_Measure: square meters Attribute: Attribute_Label: AVEG_M2 Attribute_Definition: Surface area of the vegetated part of a marsh unit in square meters. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0 Range_Domain_Maximum: 592657.33625 Attribute_Units_of_Measure: square meters Attribute: Attribute_Label: MU_ELEV Attribute_Definition: Mean elevation of a marsh unit. If the percent hydro-flattened area is greater than 25 percent (MU_HFAR is greater than 0.25), the marsh unit elevation is set to -9999 indicating insufficient elevation data. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -2.19592 Range_Domain_Maximum: 8.59673 Attribute_Units_of_Measure: meters Attribute: Attribute_Label: VG_ELEV Attribute_Definition: Mean elevation of the vegetated area in a marsh unit. If there is no vegetated area in the marsh unit, the value is set to -9999. Also, if the percent hydro-flattened area in the vegetated portion is greater than 25 percent (VG_HFAR is greater than 0.25), the value is set to -9999 indicating insufficient elevation data. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -1.37235 Range_Domain_Maximum: 8.59673 Attribute_Units_of_Measure: meters Attribute: Attribute_Label: MU_HFAR Attribute_Definition: Percent (in decimal form) of the marsh unit that contains hydro-flattened bathymetric/elevation values. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0 Range_Domain_Maximum: 1 Attribute_Units_of_Measure: none Attribute: Attribute_Label: VG_HFAR Attribute_Definition: Percent (in decimal form) of the vegetated portion of the marsh unit that contains hydro-flattened bathymetric/elevation values. If there is no vegetated area in the marsh unit, the value is set to -9999. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0 Range_Domain_Maximum: 1 Attribute_Units_of_Measure: none Attribute: Attribute_Label: SKWNSS Attribute_Definition: The measure of skewness of the elevation distribution in the vegetated part of a marsh unit. Positive skewness values (i.e., right-skewed distribution) indicate clustering of elevation distribution towards lower elevations. Negative values (left-skewed distribution) indicate clustering towards higher elevations. A value of -9999 indicates no vegetated area within the marsh unit or no elevation value for the vegetated portion. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -7.74112 Range_Domain_Maximum: 10.31490 Attribute_Units_of_Measure: none Attribute: Attribute_Label: LOW3RD Attribute_Definition: LOW3RD is the percent of elevation values that fall within the lowest third of the elevation range within the vegetated part of a marsh unit. Value of -9999 indicates no vegetated area within the marsh unit or no elevation value for the vegetated portion. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.034065 Range_Domain_Maximum: 99.65249 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 square meters; (-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 square meters. 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, mean elevation for each conceptual salt marsh unit in Maine salt marshes has been calculated based on the 1-meter ME DEM source dataset. 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 and elevation values is assumed to be 1 meter and 0.01 meter, 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_elev_ME.zip (ZIP file contains the shapefile mu_elev_ME.shp and the additional shapefile components), browse graphic (Elev_ME_Browse.png), and FGDC 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. 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: 11 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://www.sciencebase.gov/catalog/file/get/657b3ee2d34e952b2274bb36 Network_Resource_Name: https://www.sciencebase.gov/catalog/item/657b3ee2d34e952b2274bb36 Network_Resource_Name: https://doi.org/10.5066/P9FRGLB0 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/657b3ee2d34e952b2274bb36?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/657b3ee2d34e952b2274bb36?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: 20240129 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