Snake/Salt River Basin Plan - Wetlands

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Frequently-anticipated questions:

What does this data set describe?
    Title: Snake/Salt River Basin Plan - Wetlands
    Abstract:
    Original digital National Wetland Inventory digital line graphs, source scale approximately 1:24,000, converted into Arc/Info coverages with matching attributes. See graphic image or on-line linkage for availability of these quadrangles in Wyoming.

  1. How should this data set be cited?

    U.S. Fish & Wildlife Service, National Wetlands Inventory, 1997, Snake/Salt River Basin Plan - Wetlands: Spatial Data and Visualization Center, Laramie, Wyoming.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -111.046776
    East_Bounding_Coordinate: -110.000000
    North_Bounding_Coordinate: 44.000013
    South_Bounding_Coordinate: 42.500000

  3. What does it look like?

    <URL:http://www.sdvc.uwyo.edu/images/24nwi.gif>nwi.gif (GIF)
    availability of National Wetlands Inventory data in Wyoming

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 01-Feb-1971
    Ending_Date: 01-Dec-1992
    Currentness_Reference: source photography date

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • G-polygon (15816)

    2. What coordinate system is used to represent geographic features?

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.400000.
      The flattening of the ellipsoid used is 1/294.978698.

  7. How does the data set describe geographic features?

    nwi_ssdd27
    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 three 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. The Arc/Info coverage for NWI data has both polygon and arc topology, and the attributes for the .PAT and .AAT table are the same. NWI_CODE is the parent attribute, and its characters have been subdivided into other attributes for ease of selection. Two .dbf files are included with the NWI data, type.dbf and class.dbf. The field in type.dbf SYSTEM_SUB describes the codes for the wetlands subsystem (ie riverine, lacustrine, palustrine, or upland). The field in class.dbf, CLASS, describes the codes for the wetlands class, (eg rock bottom, aquatic bed, emergent). (Source: see citation)

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    AREA

    PERIMETER

    TYPE

    CLASS

    W_REGIME

    SPECIAL

    NWI_CODE

    SYSTEM

    Entity_and_Attribute_Overview:
    The wetland classification system is hierarchical, with wetlands and deepwater habitats divided among five major systems at the broadest level. The five systems include Marine (open ocean and associated coastline), Estuarine (salt marshes and brackish tidal water), Riverine (rivers, creeks, and streams), Lacustrine (lakes and deep ponds), and Palustrine (shallow ponds, marshes, swamps, sloughs). Systems are further subdivided into subsystems which reflect hydrologic conditions. Below the subsystem is the class which describes the appearance of the wetland in terms of vegetation or substrate. Each class is further subdivided into subclasses; vegetated subclasses are described in terms of life form and substrate subclasses in terms of composition. The classification system also includes modifiers to describe hydrology (water regime), soils, water chemistry (pH, salinity), and special modifiers relating to man's activities (e.g., impounded, partly drained).
    Entity_and_Attribute_Detail_Citation:
    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.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    Data Manager
    Spatial Data and Visualization Center
    Box 4008400840084008 University Station
    Laramie, Wyoming 82071
    USA

    307-766-2751 (voice)
    n/a

    Hours_of_Service: 8 AM to 5 PM MST

Why was the data set created?
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.

How was the data set created?
  1. From what previous works were the data drawn?

    NWI1 (source 1 of 3)
    Domain includes the U.S. Geolog, U.S. Department of Agriculture (USDA, 1992, Domain includes National Aerial Photography Program (NAPP), National High Altitude Photography (NHAP), Agricultural and Stabilization Conservation Service (ASCS), NASA or special project photography. Information for this element varies for each 7.5' quad. See the quad-specific metadata file..

    Type_of_Source_Media: stable based material
    Source_Scale_Denominator: 62000
    Source_Contribution:
    Wetlands spatial and attribute information. Source scales range from 1:20,000 to 1:132,000.

    NWI2 (source 2 of 3)
    U.S. Geological Survey, 1992, topographic map: U.S. Geological Survey, Reston,VA.

    Type_of_Source_Media: stable-base material
    Source_Contribution:
    Base cartographic data. Scale domain includes 20000, 24000, 25000, 30000, and 62500.

    NWI3 (source 3 of 3)
    U.S. Fish & Wildlife Service, National Wetlands Inventory, 1994, Information for this element varies for each 7.5' quad.: U.S. Fish & Wildlife Service, National Wetlands Inventory, St.Petersburg,Florida.

    Type_of_Source_Media: stable-base material
    Source_Contribution:
    wetlands location and classification. Scale domain includes 20,000, 24000. 25000, 30000, and 62500.

  2. How were the data generated, processed, and modified?

    Date: 1994 (process 1 of 4)
    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 labelled. Quality control steps occur throughout the photointerpretation, map compilation, and map reproduction processes.

    Data sources used in this process:

    • NWI1
    • NWI2

    Data sources produced in this process:

    • NWI3

    Date: 1981 (process 2 of 4)
    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 Wetlands Analytical Mapping System (WAMS) 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.

    Data sources used in this process:

    • NWI3

    Date: 1997 (process 3 of 4)
    Digital line graph files of NWI were converted into Arc/Info format, tiled into 1:100,000-scale quadrangles for distribution, and attributes standardized and checked.

    (process 4 of 4)
    Metadata imported.

    This shapefile was reprojected and clipped to the Snake/Salt Basin Boundary as part of the Wyoming Water Plan.

    Data sources used in this process:

    • C:\DOCUME~1\decook\LOCALS~1\Temp\xml95.tmp

  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?

    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, WAMS software (USFWS-NWI) tests the attributes against a master set of valid wetland attributes.

  2. How accurate are the geographic locations?

    not available at this time

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    All photo-interpretable wetlands are mapped. In the treeless prairies, 1/4 acre wetlands are mapped. In forested areas, small open water and emergent wetlands are mapped. In general, the minimum mapping unit is from 1 to 3 acres depending on the wetland type and the scale and emulsion of the source aerial photography. In regions of the country where evergreen forested wetlands predominate, wetlands smaller than 3 acres may not be mapped. Thus, a detailed on the ground and historical analysis of a single site may result in a revision of the wetland boundaries established through photographic interpretation. In addition, some small wetlands and those obscured by dense forest cover may not be included in this dataset.

  5. How consistent are the relationships among the observations, including topology?

    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 WAMS verification software (USFWS-NWI).

How can someone get a copy of the data set?
Are there legal restrictions on access or use of the data?

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.

  1. Who distributes the data set? (Distributor 1 of 1)

    Data Manager
    Spatial Data and Visualization Center
    Box 4008 University Station
    Laramie, Wyoming 82071
    USA

    307-766-2751 (voice)
    n/a

  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    The distributor shall not be held liable for improper or incorrect use of this data, based on the description of appropriate/inappropriate used described in this metadata document. It is strongly recommended that this data is directly acquired from the distributor described above or from the National Wetlands Inventory, <http://www.nwi.fws.gov> and not through other sources which may have changed the data. This data was developed and is meant to be used at the 1:24,000-scale (or smaller scale) for the purpose of identifying wetlands (by federal NWI definitions) in Wyoming and the distributor makes no claims for the data's suitability for other purposes.

  4. How can I download or order the data?

Who wrote the metadata?
Dates:
Last modified: 19-May-2004

Metadata author:
Margo Berendsen
Box 4008 University Station
Laramie, Wyoming 82071
USA

307-766-2751 (voice)
meh@uwyo.edu

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

Metadata extensions used:

Generated by mp version 2.7.33 on Wed May 19 09:05:48 2004