Conversion of Alabama 2004

Frequently-anticipated questions:


What does this data set describe?

    Title: Conversion of Alabama 2004
    Abstract:
    The United States Department of Agriculture (USDA), National Agricultural Statistics Service (NASS) area sampling frame is a delineation of all parcels of land for the purpose of later sampling the parcels. The area frame is constructed by visually interpreting satellite imagery to divide a state into homogenous land use areas (strata) based on percent cultivated. The strata are typically defined as low, medium or high percent cultivated, non-agricultural land, urban use, agri-urban, or water. The boundaries of the strata usually follow identifiable features such as roads, railroads and waterways. The strata boundaries do not coincide with any political boundaries, with the exception of state boundaries.

    Though all of the dates for this frame point to 2004, this is only when the older frame from the paper map was converted over to digital form. All of the stratification work for the paper maps and was completed in 1990.

    Supplemental_Information: N/A

  1. How should this data set be cited?
  2. United States Department of Agr, National Agricultural Statistics Service, 2004, Conversion of Alabama 2004: U.S. Department of Agriculture, National Agricultural Statistics Service, Fairfax, Virginia.

    Online Links:

  3. What geographic area does the data set cover?
  4. West_Bounding_Coordinate: -88.47
    East_Bounding_Coordinate: -84.89
    North_Bounding_Coordinate: 35.00
    South_Bounding_Coordinate: 30.22

  5. What does it look like?
  6. Does the data set describe conditions during a particular time period?
  7. Calendar_Date: 2003
    Currentness_Reference: N/A

  8. What is the general form of this data set?
  9. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
    2. Indirect_Spatial_Reference:
      U.S. Department of Commerce, 1990, Counties and Equivalent Entities of The United States, Its Possessions, and Associated Areas (Federal Information Processing Standard 6-4): Washington, D.C. National Institute of Standards and Technology.
      This is a Vector data set. It contains the following vector data types (SDTS terminology):

    3. What coordinate system is used to represent geographic features?
    4. Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 16
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -99.00
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.00
      False_Northing: 0.0

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 30
      Ordinates (y-coordinates) are specified to the nearest 30
      Planar coordinates are specified in Meters

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference 80.
      The semi-major axis of the ellipsoid used is 6378137.00.
      The flattening of the ellipsoid used is 1/298.257.

    5. How does the data set describe geographic features?
    6. Land Use Strata
      Homogeneous land use area based on percent cultivated
      (Source: U.S. Department of Agriculture, National Agricultural Statistics Service)

      Strata
      Land use category based on percent cultivated
      (Source: U.S. Department of Agriculture, National Agricultural Statistics Service)

      Land USe Based on Percent Cultivated
      Value Definition
      13
       50% CULTIVATED
      
      20 15-50% CULTIVATED
      31 AGRI-URBAN, MORE THAN 20 DWELLINGS PER SQ. MILE
      32 RESIDENTIAL-COMMERCIAL, > 20 DWELLINGS PER SQ. MILE
      40 < 15% CULTIVATED
      50 NON AGRICULTURAL

      Sum_area
      The stratum area in square miles.
      (Source: U.S. Department of Agriculture, National Agricultural Statistics Service)

      Stratum Area in Square Miles
      Range of values
      Minimum: 105.83 (actual value, not range)
      Maximum: 35,361.18

      Sum_acres
      The amount of acres in a stratum.
      (Source: U.S. Department of Agriculture, National Agricultural Statistics Service)

      Number of Acres in Stratum
      Range of values
      Minimum: 67,731.13 (actual value, not range)
      Maximum: 22,631,158.16 (actual value, not range)


      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. Area Frame Section staff

      4. To whom should users address questions about the data?
      5. USDA/NASS
        1400 Independence Ave. SW
        Washington, D.C. 20250

        Customer Service: 1-800-727-9540



      Why was the data set created?

      These data are intended for geographic display and analysis at the state level. The data should be displayed and analyzed at a scale of 1:100,000 or smaller (e.g., 1:250,000, etc.). The strata data are provided "as is". USDA/NASS does not warrant results you may obtain using the strata data.


      How was the data set created?

      1. From what previous works were the data drawn?
      2. TopoDRG100
        (source 1 of 6)
        U.S. Geologic Survey (USGS), 1979 - 1991, USGS Topographic Quadrangles: U.S. Geologic Survey, Reston, VA.

        Type_of_Source_Media: On-line
        Source_Scale_Denominator: 100000
        Source_Contribution: Spatial and attribute information

        NAPP
        (source 2 of 6)
        Agency, Farm Service , 1999, National Aerial Photography Program (NAPP): Aerial Photography Field Office (APFO), Salt Lake City, UT.

        Type_of_Source_Media: CD-Rom
        Source_Scale_Denominator: 40000
        Source_Contribution: Spatial and attribute information

        TopoDRG24
        (source 3 of 6)
        U.S. Geological Survey (USGS), 1979 - 1991, USGS Topographic Quadrangles: U.S. Geological Survey, Reston, VA.

        Type_of_Source_Media: On-line
        Source_Scale_Denominator: 24000
        Source_Contribution: Spatial and attribute information

        TIGER
        (source 4 of 6)
        United States Census Bureau, 2000, TIGER Digital Vector Files: U.S. Census Bureau, Suitland, MD.

        Type_of_Source_Media: CD-Rom
        Source_Contribution: Spatial and attribute information

        TM5
        (source 5 of 6)
        NASA, 1987 & 1986, Landsat 5 Thematic Mapper Imagery: Space Imaging, Lanham, MD.

        Type_of_Source_Media: Paper
        Source_Scale_Denominator: 250000
        Source_Contribution: Spatial and attribute information

        AFSPaper
        (source 6 of 6)
        National Agricultural Statistics Service, 2003, Area Frame Design for Agricultural Surveys: NASS/USDA, Washington, DC.

        Type_of_Source_Media: Paper
        Source_Contribution: Spatial and attribute information

      3. How were the data generated, processed, and modified?
      4. Date: 2003 (process 1 of 1)
        The area sampling frame for Alabama was constructed for use in 2004
        and was based on USGS 1:24,000 and 1:100,000 scale topographic maps, 1:250,000 scale Landsat imagery, and 2 meter resolution NAPP imagery. Individual county files were merged into single statefile. The coordinates for the strata polygons are unprojected to geographic latitude and longitude (decimal degrees). The spatial data file format is Environmental Systems Research Institute's ArcView shapefile format. Gaps and overlaps were corrected within and ESRI personal geodatabase.

        Though all of the dates for this frame point to 2004, this is only when the older frame from the paper map was converted over to digital form. All of the stratification work for the paper maps and was completed in 1990.

        Data sources used in this process:

      5. 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?
      2. How accurate are the geographic locations?
      3. The sources used for digitizing strata boundaries are 1:100,000 scale Digital Raster Graphics

      4. How accurate are the heights or depths?
      5. Where are the gaps in the data? What is missing?
      6. There are known gaps and overlaps. This data set includes the area in square miles and number of acres for each strata. Boundaries may not be coincident with strata boundaries of adjacent states.

      7. How consistent are the relationships among the observations, including topology?
      8. Checks for topological consistency were performed on this data set.


      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:
      None. Acknowledgment of the U.S. Department of Agriculture, National Agricultural Statistics Service would be appreciated in products derived from these data.

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

        USDA/NASS/RDD
        1400 Independence Ave SW
        Washington, D.C. 20250

        Contact_Instructions: N/A
      3. What's the catalog number I need to order this data set?
      4. What legal disclaimers am I supposed to read?
      5. Users of the strata data are solely responsible for interpretations made from the product. The strata data are provided "as is". USDA/NASS does not warrant results you may obtain by using the strata data. Feel free to contact our staff at (HQ_RD_OD@nass.usda.gov) if technical questions arise in the use of the strata data.

      6. How can I download or order the data?


      Who wrote the metadata?

      Dates:
      Last modified: 16-Jan-2014

      Metadata author:
      USDA/NASS/RDD
      1400 Independence Ave. SW
      Washington, D.C. 20250
      Metadata standard:
      FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)


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