National Wetlands Inventory (NWI) Metadata NOTE: This metadata document represents the static text elements of the National Wetlands Inventory (NWI) Metadata. Quad-specific metadata files are available through the FGDC Clearinghouse website. Metadata: Identification_Information: Citation: Citation_Information: Originator: U.S. Fish & Wildlife Service, National Wetlands Inventory Publication_Date: Ranges from Oct. 1981 to present; information for this element varies for each 7.5' quad. See the quad-specific metadata file. Title: National Wetlands Inventory -- Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Publication_Information: Publication_Place: St.Petersburg, Florida Publisher: U.S. Fish & Wildlife Service, National Wetlands Inventory Online_Linkage: ftp://ftp.nwi.fws.gov/arcdata/ ftp://ftp.nwi.fws.gov/shapedata/ Description: Abstract: NWI digital data files are records of wetlands location and classification as developed by the U.S. Fish & Wildlife Service. The classification system was adopted as a national classification standard in 1996 by the Federal Geographic Data Committee. This dataset is one of a series available in 7.5 minute by 7.5 minute blocks containing ground planimetric coordinates of wetlands point, line, and polygon features and wetlands attributes. When completed, the series will provide coverage for all of the contiguous United States, Hawaii, Alaska, and U.S. protectorates in the Pacific and Caribbean. Coverage includes both digital data and hardcopy maps. The NWI maps do not show all wetlands since the maps are derived from aerial photointerpretation with varying limitations due to scale, photo quality, inventory techniques, and other factors. Consequently, the maps tend to show wetlands that are readily photointerpreted given consideration of photo and map scale. In general, the older NWI maps prepared from 1970s-era black and white photography (1:80,000 scale) tend to be very conservative, with many forested and drier-end emergent wetlands (e.g., wet meadows) not mapped. Maps derived from color infrared photography tend to yield more accurate results except when this photography was captured during a dry year, making wetland identification equally difficult. Proper use of NWI maps therefore requires knowledge of the inherent limitations of this mapping. It is suggested that users also consult other information to aid in wetland detection, such as U.S. Department of Agriculture soil survey reports and other wetland maps that may have been produced by state and local governments, and not rely solely on NWI maps. See section on "Completeness_Report" for more information. Also see an article in the National Wetlands Newsletter (March-April 1997; Vol. 19/2, pp. 5-12) entitled "NWI Maps: What They Tell Us" (a free copy of this article can be ordered from U.S. Fish and Wildlife Service, ES-NWI, 300 Westgate Center Drive, Hadley, MA 01035, telephone, 413-253-8620). Purpose: The data provide consultants, planners, and resource managers with information on wetland location and type. The data were collected to meet U.S. Fish & Wildlife Service's mandate to map the wetland and deepwater habitats of the United States. The purpose of this survey was not to map all wetlands and deepwater habitats of the United States, but rather to use aerial photointerpretation techniques to produce thematic maps that show, in most cases, the larger ones and types that can be identified by such techniques. The objective was to provide better geospatial information on wetlands than found on the U.S. Geological Survey topographic maps. It was not the intent of the NWI to produce maps that show exact wetland boundaries comparable to boundaries derived from ground surveys. Boundaries are therefore generalized in most cases. Consequently, the quality of the wetland data is variable mainly due to source photography, ease or difficulty of interpreting specific wetland types, and survey methods (e.g., level of field effort and state-of-the-art of wetland delineation). See section on "Completeness_Report" for more information. Time_Period_of_Content: Time_Period_Information: Multiple_Dates_Times: Calendar_Date: Ranges from Feb. 1971 to Nov. 1997. Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Currentness_Reference: Source photography date Status: Progress: Complete Maintenance_and_Update_Frequency: Irregular Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: Information for this element varies for each 7.5' quad. See the quad-specific metadata file. East_Bounding_Coordinate: Information for this element varies for each 7.5' quad. See the quad-specific metadata file. North_Bounding_Coordinate: Information for this element varies for each 7.5' quad. See the quad-specific metadata file. South_Bounding_Coordinate: Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: wetlands Theme_Keyword: hydrologic Theme_Keyword: land cover Theme_Keyword: surface and manmade features Place: Place_Keyword_Thesaurus: USGS Quadrangle Names Place_Keyword: Range includes all 50 states, Puerto Rico, Virgin Islands. Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Access_Constraints: None Use_Constraints: Federal, State, and local regulatory agencies with jurisdiction over wetlands may define and describe wetlands in a different manner than that used in this inventory. There is no attempt, in either the design or products of this inventory, to define the limits of proprietary jurisdiction of any Federal, State, or local government or to establish the geographical scope of the regulatory programs of government agencies. Persons intending to engage in activities involving modifications within or adjacent to wetland areas should seek the advice of appropriate Federal, State, or local agencies concerning specified agency regulatory programs and proprietary jurisdictions that may affect such activities. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Fish & Wildlife Service, National Wetlands Inventory Center Contact_Position: Cartographer Contact_Address: Address_Type: Mailing and Physical address Address: 9720 Executive Center Drive City: St. Petersburg State_or_Province: Florida Postal_Code: 33702 Country: US Contact_Voice_Telephone: 727-570-5400 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The attribute accuracy is tested by manual comparison of the source with hard copy printouts and/or symbolized display of the digital wetlands data on an interactive computer graphic system. In addition, quality control verification software (USFWS-NWI) tests the attributes against a master set of valid wetland attributes. Logical_Consistency_Report: Polygons intersecting the neatline are closed along the border. Segments making up the outer and inner boundaries of a polygon tie end-to-end to completely enclose the area. Line segments are a set of sequentially numbered coordinate pairs. No duplicate features exist nor duplicate points in a data string. Intersecting lines are separated into individual line segments at the point of intersection. Point data are represented by two sets of coordinate pairs, each with the same coordinate values. All nodes are represented by a single coordinate pair which indicates the beginning or end of a line segment. The neatline is generated by connecting the four corners of the digital file, as established during initialization of the digital file. All data crossing the neatline are clipped to the neatline and data within a specified tolerance of the neatline are snapped to the neatline. Tests for logical consistency are performed by quality control verification software (USFWS-NWI). Completeness_Report: NWI maps do not show all wetlands, but attempt to show most photointerpretable wetlands given considerations of map/photo scale and wetland delineation practices. A target mapping unit (tmu) is an estimate of the size class of the smallest group of wetlands that NWI attempts to map consistently; it is not the smallest wetland mapped. Recognize that some wetland types are conspicuous and readily mapped (e.g., marshes and ponds) and smaller ones may be mapped. Drier wetlands and forested wetlands (especially evergreen) are more difficult to photointerpret and larger ones may be missed. The tmu also varies with photo scale; in forested regions, the tmu may be 3-5 acres (1:80K photos), 1-3 acres (1:58K), or 1 acre (1:40K). NWI maps should show most wetlands larger than the tmu. In the treeless prairies, a 1/4 acre tmu is possible due to the openness of terrain and occurrence of wetlands in distinct depressions. Take notice of the photo scale/type used to make the maps (see legend) and realize that black and white photos tend to yield more conservative interpretations than color infrared film. Most farmed wetlands (e.g., mucklands) are usually not mapped, except for pothole-type wetlands, cranberry bogs, and diked former tidelands (Sacramento Valley). Partly drained wetlands are conservatively mapped due to photointerpretation limitations. No attempt was made to identify regulated wetlands from other wetlands. Recognize that maps produced through photointerpretation are not as accurate as one prepared from on-the-ground surveys, so NWI boundaries are generalized. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Horizontal Lineage: Source_Information: Source_Citation: Originator: The Domain includes U.S. Geological Survey (USGS), U.S. Department of Agriculture (USDA), National Aeronautics and Space Administration (NASA), special project. Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Publication_Date: Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Title: The Domain includes National Aerial Photography Program (NAPP), National High Altitude Photography (NHAP), USDA, Farm Service Agency, Aerial Photography Field Office, NASA or special project photography. Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Geospatial_Data_Presentation_Form: Remote-sensing image Publication_Information: Publication_Place: Reston, Virginia Publisher: U.S. Geological Survey Source_Scale_Denominator: Ranges from 20,000 to 132,000. Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Type_of_Source_Media: Domain includes black and white, color infrared, or natural color aerial photograph film transparency. Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Source_Time_Period_of_Content: Time_Period_Information: Multiple_Dates_Times: Calendar_Date: Ranges from Feb. 1971 to Nov. 1997. Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Source_Currentness_Reference: Photo date Source_Citation_Abbreviation: PHOTOS Source_Contribution: Wetlands spatial and attribute information Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: Ranges from 1902 to 1995. Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Title: topographic map Geospatial_Data_Presentation_Form: map Publication_Information: Publication_Place: Reston, Virginia Publisher: U.S. Geological Survey Source_Scale_Denominator: Domain includes 20000, 24000, 25000, 30000, and 62500. Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Type_of_Source_Media: stable-base material Source_Time_Period_of_Content: Time_Period_Information: Single_Date_Time: Calendar_Date: Ranges from 1902 to 1995. Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Source_Currentness_Reference: publication date Source_Citation_Abbreviation: USGS QUAD Source_Contribution: base cartographic data Source_Information: Source_Citation: Citation_Information: Originator: U.S.D.A. Natural Resources Conservation Service Publication_Date: Varies Title: County Soil Surveys Geospatial_Data_Presentation_Form: map Publication_Information: Publication_Place: Washington, DC Publisher: Government Printing Office Source_Scale_Denominator: Varies Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date_Time: Calendar_Date: Varies Source_Currentness_Reference: publication date Source_Citation_Abbreviation: SOILS Source_Contribution: wetlands location and classification Process_Step: Process_Description: NWI maps are compiled through manual photointerpretation of NHAP or NAPP aerial photography supplemented by Soil Surveys and field checking of wetland photo signatures. Delineated wetland boundaries are manually transferred from interpreted photos to USGS 7.5 minute topographic quadrangle maps and then manually labeled. Quality control steps occur throughout the photointerpretation, map compilation, and map reproduction processes. Digital wetlands data are either manually digitized or scanned from stable-base copies of the 1:24,000 scale wetlands overlays registered to the standard U.S. Geological Survey (USGS) 7.5 minute quadrangles into topologically correct data files using Arc/Info software. Files contain ground planimetric coordinates and wetland attributes. The quadrangles were referenced to the North American Datum of 1927 (NAD27) horizontal datum. The scanning process captured the digital data at a scanning resolution of at least 0.001 inches; the resulting raster data were vectorized and then attributed on an interactive editing station. Manual digitizing used a digitizing table to capture the digital data at a resolution of at least 0.005 inches; attribution was performed as the data were digitized. The determination of scanning versus manual digitizing production method was based on feature density, source map quality, feature symbology, and availability of production systems. The data were checked for position by comparing plots of the digital data to the source material. Source_Used_Citation_Abbreviation: PHOTOS Source_Used_Citation_Abbreviation: USGS QUADS Process_Date: Ranges from 1979 to 2001. Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Source_Produced_Citation_Abbreviation: NWI Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: Ranges from 4 to 20. Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.9996 Longitude_of_Central_Meridian: Ranges from -159.0 to -63.0. Information for this element varies for each 7.5' quad. See the quad-specific metadata file. Latitude_of_Projection_Origin: 0.0 False_Easting: 500000.0 False_Northing: 0.0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: Coordinate pair Coordinate_Representation: Abscissa_Resolution: 0.61 Ordinate_Resolution: 0.61 Planar_Distance_Units: Meters Geodetic_Model: Horizonal_Datum_Name: North American Datum of 1927 Ellipsoid_Name: Clarke 1866 Semi_major_Axis: 6378206.4 Denominator_of_Flattening_Ratio: 294.9787 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: Wetland Entity_Type_Definition: Wetlands are lands transitional between terrestrial and aquatic systems where the water table is usually at or near the surface or the land is covered by shallow water. For purposes of this classification wetlands must have one or more of the following attributes: 1) at least periodically, the land supports predominantly hydrophytes; 2) the substrate is predominantly undrained hydric soil; and 3) the substrate is non-soil and is saturated with water or covered by shallow water at some time during the growing season of each year. Entity_Type_Definition_Source: Cowardin, L.M., V. Carter, F. Golet, and E. LaRoe. 1979. Classification of wetlands and deepwater habitats of the United States. U.S. Fish Wildlife Service. 103 pp. Attribute: Attribute_Label: Wetland classification Attribute_Definition: Classification of the Wetland Attribute_Definition_Source: Cowardin, L.M., V. Carter, F. Golet, and E. LaRoe. 1979. Classification of wetlands and deepwater habitats of the United States. U.S. Fish Wildlife Service. 103 pp. Attribute_Domain_Values: Codeset_Domain: Codeset_Name: Valid wetland classification code list Codeset_Source: Photointerpretation Conventions for the National Wetlands Inventory, January 1995 Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: Cooperator-Run Distribution Centers Contact_Address: Address_Type: List@www.nwi.fws.gov/Maps/distribution_ctrs.htm Distribution_Liability: None Standard_Order_Process: Non_digital_Form: Hardcopy NWI wetlands maps at various scales, on diazo paper composited with USGS base map. Digital_Form: Digital_Transfer_Information: Format_Name: Arc Export and Shapefile Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: ftp://ftp.nwi.fws.gov/arcdata/ ftp://ftp.nwi.fws.gov/shapedata/ Network_Resource_Name: http://www.nwi.fws.gov/ Access_Instructions: Anyone with access to the Internet may connect to NWI's server via anonymous ftp and download available NWI digital wetlands data in Arc Export and Shapefile formats. Indexes for NWI hardcopy maps and digital data are also available. Digital wetlands data can be downloaded for 7.5 minute quadrangles throughout the USA. To access: ftp to the NWI server, login as anonymous, enter your e-mail address at the password prompt, change to the arcdata directory for Arc Export data, or change to the shapedata directory for Shapefile data. Use the ftp 'get' command to transfer readme file for further instructions. View the NWI home page by pointing your World Wide Web browser to the http address shown above. Online_Computer_and_Operating_System: Sun Model 450 Unix server. Solaris 8 operating system. Offline_Option: Offline_Media: Arc Export Everything Tape - 8mm cartridge tape (5 Gb) Recording_Capacity: Recording_Density: 5 Recording_Density_Units: gigabytes Recording_Format: tar Metadata_Reference_Information: Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Andrew Paul Contact_Organization: U.S. Fish & Wildlife Service, National Wetlands Inventory Center Contact_Position: Cartographer Contact_Address: Address_Type: Mailing and Physical address Address: 9720 Executive Center Drive City: St. Petersburg State_or_Province: Florida Postal_Code: 33702 Contact_Voice_Telephone: 727-570-5400 Contact_Facsimile_Telephone: 727-570-5420 Contact_Electronic_Mail_Address: Andrew_Paul@fws.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998