Metadata:
  Identification_Information:
    Citation:
      Citation_Information:
        Originator: U.S. Environmental Protection Agency
        Publication_Date: 200506
        Title: Omerniks Level III Ecoregions of the Continental United States
        Publication_Information:
          Publication_Place: Reston, VA
          Publisher: National Atlas of the United States
        Online_Linkage: <http://nationalatlas.gov/atlasftp.html?openChapters=chpbio#chpbio>
    Description:
      Abstract:
        This map layer shows Omerniks Level III ecoregions, derived from a
        1:7,500,000 map created by J.M. Omernik in 1987 and from refinements of
        Omernik's framework that were made for other projects.  Ecoregions
        describe areas of general similarity in ecosystems and in the type,
        quality, and quantity of environmental resources.  Omerniks ecoregions
        are based on the premise that a hierarchy of ecological regions can be
        identified through the analysis of the patterns and the composition of
        both living and nonliving phenomena, such as geology, physiography,
        vegetation, climate, soils, land use, wildlife, and hydrology, that affect
        or reflect differences in ecosystem quality and integrity.  All the
        characteristics are considered when determining ecoregions, but the
        relative importance of each characteristic may vary from one ecoregion to
        another.  Level III is the most detailed level available nationally for
        this system of ecoregions.
      Purpose:
        These data are intended for geographic display and analysis at the
        national level, and for large regional areas.  The data should be
        displayed and analyzed at scales appropriate for 1:7,500,000-scale data.
        No responsibility is assumed by the National Atlas of the United States in
        the use of these data.
      Supplemental_Information:
        Detailed descriptions of the ecological regions represented in this map
        layer are available from the U.S. Environmental Protection Agency (EPA),
        Western Ecology Division at:
        <http://www.epa.gov/wed/pages/ecoregions/level_iii.htm>.  EPA also offers
        data of Omerniks Level III Ecoregions on the same site; the file includes
        the same ecoregions as are available through the National Atlas but uses
        EPA shorelines and State boundaries.

        A bibliography of ecoregion/biocriteria publications, called
        Ecoomr_Biblio.txt, is bundled with the downloadable data.  Each reference
        in the bibliography has a code; the codes are used for any citations in
        this metadata file.

        Ecoregions denote areas of general similarity in ecosystems and the type,
        quantity, and quality of environmental resources; they are designed to
        serve as a spatial framework for the research, assessment, management, and
        monitoring of ecosystems and ecosystem components.  By recognizing the
        spatial differences in the capacities and potentials of ecosystems,
        ecoregions stratify the environment by its probable response to
        disturbance (BR-1-98).  These general purpose regions are critical for
        structuring and implementing ecosystem management strategies across
        Federal agencies, State agencies, and nongovernmental organizations that
        are responsible for different types of resources within the same
        geographic areas (OM-1-00, OM-1-04).

        The approach used to compile these ecoregions is based on the premise that
        ecological regions are hierarchical and can be identified through the
        analysis of the spatial patterns and composition of biotic and abiotic
        phenomena that affect or reflect differences in ecosystem quality and
        integrity (WI-1-86, OM-1-87, OM-1-95, OM-1-04).  These phenomena include
        geology, physiography, vegetation, climate, soils, land use, wildlife,
        water quality, and hydrology.  In the regionalization process, the full
        range of characteristics is examined and integrated at each scale or level
        of resolution.  The relative importance of each characteristic varies from
        one ecological region to another regardless of the hierarchical level.
        Level I is the coarsest level of the hierarchy, dividing North America
        into 15 ecological regions.  Level II divides the continent into 52
        regions (CE-1-97).  At level III, the continental United States contains
        104 ecoregions, with the conterminous United States having 84 (US-1-03).
        More detailed level IV ecoregions have been delineated, or are in the
        process of being mapped, for approximately 85 percent of the conterminous
        United States.

        Since 1994, when the National Interagency Technical Team (NITT) was formed
        to develop a common framework of ecological regions (MM-1-01), efforts
        have been made to include all of the major federal resource management
        agencies in the level IV ecoregion mapping projects.  The goal of each of
        these collaborative projects has been to attain consensus across agencies
        and ultimately to develop a consistent ecoregion framework for the entire
        nation.

        Because the collaborative projects to map level IV ecoregions often result
        in refined level III boundaries, the map of level III ecoregions is
        periodically revised.  Likewise, much of the recent work to refine level
        III boundaries and define level IV ecoregions has resulted in slight
        differences between these two levels and the coarser level I and II
        regions mapped earlier by the CEC.

        Level IV ecoregions data and maps can be accessed through the
        Environmental Protection Agency Level IV Ecoregions page at
        <http://www.epa.gov/wed/pages/ecoregions/level_iv.htm>.
    Time_Period_of_Content:
      Time_Period_Information:
        Single_Date/Time:
          Calendar_Date: 200302
      Currentness_Reference: Publication date of primary source material
    Status:
      Progress: Complete
      Maintenance_and_Update_Frequency: Irregular
    Spatial_Domain:
      Bounding_Coordinates:
        West_Bounding_Coordinate: 178
        East_Bounding_Coordinate: -66
        North_Bounding_Coordinate: 53
        South_Bounding_Coordinate: 25
    Keywords:
      Theme:
        Theme_Keyword_Thesaurus: ISO 19115 Topic Category
        Theme_Keyword: biota
        Theme_Keyword: environment
      Theme:
        Theme_Keyword_Thesaurus: None
        Theme_Keyword: Ecoregions
        Theme_Keyword: Omerniks ecoregions
        Theme_Keyword: Ecological regions
        Theme_Keyword: Ecosystems
        Theme_Keyword: Regional ecology
        Theme_Keyword: Ecosystem geography
        Theme_Keyword: Mapping
      Place:
        Place_Keyword_Thesaurus: None
        Place_Keyword: United States
      Place:
        Place_Keyword_Thesaurus:
          U.S. Department of Commerce, 1987, Codes for the Identification of the
          States, the District of Columbia and the Outlying Areas of The United
          States, and Associated Areas (FIPS 5-2): Washington, DC, National
          Institute of Standards and Technology.
        Place_Keyword: Alabama
        Place_Keyword: Alaska
        Place_Keyword: Arizona
        Place_Keyword: Arkansas
        Place_Keyword: California

        Place_Keyword: Colorado
        Place_Keyword: Connecticut
        Place_Keyword: Delaware
        Place_Keyword: District of Columbia
        Place_Keyword: Florida
        Place_Keyword: Georgia
        Place_Keyword: Idaho
        Place_Keyword: Illinois
        Place_Keyword: Indiana
        Place_Keyword: Iowa
        Place_Keyword: Kansas
        Place_Keyword: Kentucky
        Place_Keyword: Louisiana
        Place_Keyword: Maine
        Place_Keyword: Maryland
        Place_Keyword: Massachusetts
        Place_Keyword: Michigan
        Place_Keyword: Minnesota
        Place_Keyword: Mississippi
        Place_Keyword: Missouri
        Place_Keyword: Montana
        Place_Keyword: Nebraska
        Place_Keyword: Nevada
        Place_Keyword: New Hampshire
        Place_Keyword: New Jersey
        Place_Keyword: New Mexico
        Place_Keyword: New York
        Place_Keyword: North Carolina
        Place_Keyword: North Dakota
        Place_Keyword: Ohio
        Place_Keyword: Oklahoma
        Place_Keyword: Oregon
        Place_Keyword: Pennsylvania
        Place_Keyword: Rhode Island
        Place_Keyword: South Carolina
        Place_Keyword: South Dakota
        Place_Keyword: Tennessee
        Place_Keyword: Texas
        Place_Keyword: Utah
        Place_Keyword: Vermont
        Place_Keyword: Virginia
        Place_Keyword: Washington
        Place_Keyword: West Virginia
        Place_Keyword: Wisconsin
        Place_Keyword: Wyoming

    Access_Constraints: None
    Use_Constraints:
      None.  Acknowledgment of the U.S. Environmental Protection Agency and (or)
      the National Atlas of the United States of America would be appreciated in
      products derived from these data.
    Point_of_Contact:
      Contact_Information:
        Contact_Person_Primary:
          Contact_Person: James M. Omernik
          Contact_Organization: U.S. Environmental Protection Agency, Western Ecology Division
        Contact_Address:
          Address_Type: Mailing and physical address
          Address: 200 SW 35th Street
          City: Corvallis
          State_or_Province: OR
          Postal_Code: 97333
          Country: USA
        Contact_Voice_Telephone: 541-754-4458
        Contact_Facsimile_Telephone: 541-754-4716
        Contact_Electronic_Mail_Address: omernik.james@epa.gov
    Native_Data_Set_Environment: SunOS UNIX, ARC/INFO version 8.3.
    Cross_Reference:
      Citation_Information:
        Originator: James M. Omernik
        Publication_Date: 1987
        Title: Ecoregions of the conterminous United States (map supplement)
        Edition: 1
        Geospatial_Data_Presentation_Form: Map
        Series_Information:
          Series_Name: Annals of the Association of American Geographers
          Issue_Identification: 77(1)
        Publication_Information:
          Publication_Place: Washington, DC
          Publisher: Association of American Geographers
    Cross_Reference:
      Citation_Information:
        Originator: USDA Forest Service
        Publication_Date: 200403
        Title:
          Baileys Ecoregions and Subregions of the United States, Puerto Rico,
          and the U.S. Virgin Islands
        Geospatial_Data_Presentation_Form: Map
        Publication_Information:
          Publication_Place: Reston, VA
          Publisher: National Atlas of the United States
        Online_Linkage: <http://nationalatlas.gov/atlasftp.html?openChapters=chpbio#chpbio>
        Online_Linkage: <http://www.fs.fed.us/institute/ecoregions/eco_download.html>

  Data_Quality_Information:
    Logical_Consistency_Report: No checks for topological consistency were performed on this map layer.
    Completeness_Report:
      This map layer includes Level III ecoregions information for the
      conterminous United States and Alaska.
    Lineage:
      Source_Information:
        Source_Citation:
          Citation_Information:
            Originator: Omernik, J.M.
            Publication_Date: 2003
            Title: Level III Ecoregions of the continental United States
            Geospatial_Data_Presentation_Form: Vector digital data
            Publication_Information:
              Publication_Place: Corvallis, OR
              Publisher: U.S. Environmental Protection Agency
            Online_Linkage: <http://www.epa.gov/wed/pages/ecoregions/level_iii.htm>
        Source_Scale_Denominator: 7500000
        Type_of_Source_Media: Online
        Source_Time_Period_of_Content:
          Time_Period_Information:
            Single_Date/Time:
              Calendar_Date: 200302
          Source_Currentness_Reference: Publication date
        Source_Citation_Abbreviation: US Ecoregions
        Source_Contribution: Spatial and attribute information

      Source_Information:
        Source_Citation:
          Citation_Information:
            Originator: Omernik, J.M.
            Publication_Date: 2000
            Title: Ecoregions of North America
            Geospatial_Data_Presentation_Form: Vector digital data
            Publication_Information:
              Publication_Place: Corvallis, OR
              Publisher: U.S. Environmental Protection Agency
            Online_Linkage: <http://www.epa.gov/wed/pages/ecoregions/na_eco.htm>
        Source_Scale_Denominator: 12500000
        Type_of_Source_Media: Online
        Source_Time_Period_of_Content:
          Time_Period_Information:
            Single_Date/Time:
              Calendar_Date: 2000
          Source_Currentness_Reference: Publication date
        Source_Citation_Abbreviation: NA Ecoregions
        Source_Contribution: Spatial and attribute information

      Source_Information:
        Source_Citation:
          Citation_Information:
            Originator: National Atlas of the United States
            Publication_Date: 200506
            Title: State Boundaries of the United States
            Publication_Information:
              Publication_Place: Reston, VA
              Publisher: National Atlas of the United States
            Online_Linkage: <http://nationalatlas.gov/atlasftp.html?openChapters=chpbound#chpbound>
        Source_Scale_Denominator: 2000000
        Type_of_Source_Media: Online
        Source_Time_Period_of_Content:
          Time_Period_Information:
            Range_of_Dates/Times:
              Beginning_Date: 1972
              Ending_Date: 2005
          Source_Currentness_Reference: Ground condition
        Source_Citation_Abbreviation: Atlas-States
        Source_Contribution: Spatial information

      Process_Step:
        Process_Description:
          The US Ecoregions and NA Ecoregions files were downloaded and
          reprojected to a Lambert Azimuthal Equal Area projection using
          ArcGIS 9.0.  The shorelines in US Ecoregions were deleted.  Alaska
          was clipped from in NA Ecoregions, placed in a new file, and the
          shorelines were deleted.  The resulting files were combined along with
          shorelines from the Atlas-States map layer.  Line work was cleaned and
          adjusted.  The polygon attribution from US Ecoregions and NA Ecoregions
          was copied into the data and checked.
        Source_Used_Citation_Abbreviation: US Ecoregions
        Source_Used_Citation_Abbreviation: NA Ecoregions
        Source_Used_Citation_Abbreviation: Atlas-States
        Process_Date: 200503

  Spatial_Data_Organization_Information:
    Direct_Spatial_Reference_Method: Vector
    Point_and_Vector_Object_Information:
      SDTS_Terms_Description:
        SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains
        Point_and_Vector_Object_Count: 3075

  Spatial_Reference_Information:
    Horizontal_Coordinate_System_Definition:
      Geographic:
        Latitude_Resolution: 0.000278
        Longitude_Resolution: 0.000278
        Geographic_Coordinate_Units: Decimal degrees
      Geodetic_Model:
        Horizontal_Datum_Name: North American Datum of 1983
        Ellipsoid_Name: GRS1980
        Semi-major_Axis: 6378137.0
        Denominator_of_Flattening_Ratio: 298.257222

  Entity_and_Attribute_Information:
    Detailed_Description:
      Entity_Type:
        Entity_Type_Label: Ecoregion (described by ecoomrp075.dbf)
        Entity_Type_Definition:
          A region that denotes an area of general similarity in ecosystems and
          in the type, quality, and quantity of environmental resources.  The
          polygons in this map layer represent Omernik Level III ecoregions.
        Entity_Type_Definition_Source: National Atlas of the United States
      Attribute:
        Attribute_Label: Shape
        Attribute_Definition: The representation of the entity in the data.
        Attribute_Definition_Source: National Atlas of the United States
        Attribute_Domain_Values:
          Enumerated_Domain:
            Enumerated_Domain_Value: Polygon
            Enumerated_Domain_Value_Definition: 2-dimensional element
            Enumerated_Domain_Value_Definition_Source: ESRI GIS software
      Attribute:
        Attribute_Label: Area
        Attribute_Definition:
          The size of the shape in coverage units.  In the distributed file,
          coverage units represent square decimal degrees.
        Attribute_Definition_Source: National Atlas of the United States
        Attribute_Domain_Values:
          Range_Domain:
            Range_Domain_Minimum: 0.00000
            Range_Domain_Maximum: 50.151550
      Attribute:
        Attribute_Label: Perimeter
        Attribute_Definition:
          The perimeter of the shape in coverage units.  In the distributed
          file, coverage units represent decimal degrees.
        Attribute_Definition_Source: National Atlas of the United States
        Attribute_Domain_Values:
          Range_Domain:
            Range_Domain_Minimum: 0.00857
            Range_Domain_Maximum: 261.67570
      Attribute:
        Attribute_Label: Ecoomrp075
        Attribute_Definition: Internal feature number.
        Attribute_Definition_Source: National Atlas of the United States
        Attribute_Domain_Values:
          Range_Domain:
            Range_Domain_Minimum: 2
            Range_Domain_Maximum: 3076
      Attribute:
        Attribute_Label: Level3
        Attribute_Definition: The numeric code of the Level III ecoregion.
        Attribute_Definition_Source: National Atlas of the United States
        Attribute_Domain_Values:
          Range_Domain:
            Range_Domain_Minimum: 1
            Range_Domain_Maximum: 120
      Attribute:
        Attribute_Label: Level3_name
        Attribute_Definition: The name of the Level III ecoregion.
        Attribute_Definition_Source: National Atlas of the United States
        Attribute_Domain_Values:
          Enumerated_Domain:
            Enumerated_Domain_Value: (see table below)
            Enumerated_Domain_Value_Definition:
              A full description of the ecoregions can be found at
              <ftp://ftp.epa.gov/wed/ecoregions/us/useco_desc.doc>
              > Code   Name
              >-------------------------------------------------------------------
              > 1      Coast Range
              > 2      Puget Lowland
              > 3      Willamette Valley
              > 4      Cascades
              > 5      Sierra Nevada
              > 6      Southern and Central California Chaparral and Oak Woodlands
              > 7      Central California Valley
              > 8      Southern California Mountains
              > 9      Eastern Cascades Slopes and Foothills
              > 10     Columbia Plateau
              > 11     Blue Mountains
              > 12     Snake River Plain
              > 13     Central Basin and Range
              > 14     Mojave Basin and Range
              > 15     Northern Rockies
              > 16     Idaho Batholith
              > 17     Middle Rockies
              > 18     Wyoming Basin
              > 19     Wasatch and Uinta Mountains
              > 20     Colorado Plateaus
              > 21     Southern Rockies
              > 22     Arizona/New Mexico Plateau
              > 23     Arizona/New Mexico Mountains
              > 24     Chihuahuan Deserts
              > 25     High Plains
              > 26     Southwestern Tablelands
              > 27     Central Great Plains
              > 28     Flint Hills
              > 29     Cross Timbers
              > 30     Edwards Plateau
              > 31     Southern Texas Plains
              > 32     Texas Blackland Prairies
              > 33     East Central Texas Plains
              > 34     Western Gulf Coastal Plain
              > 35     South Central Plains
              > 36     Ouachita Mountains
              > 37     Arkansas Valley
              > 38     Boston Mountains
              > 39     Ozark Highlands
              > 40     Central Irregular Plains
              > 41     Canadian Rockies
              > 42     Northwestern Glaciated Plains
              > 43     Northwestern Great Plains
              > 44     Nebraska Sand Hills
              > 45     Piedmont
              > 46     Northern Glaciated Plains
              > 47     Western Corn Belt Plains
              > 48     Lake Agassiz Plain
              > 49     Northern Minnesota Wetlands
              > 50     Northern Lakes and Forests
              > 51     North Central Hardwood Forests
              > 52     Driftless Area
              > 53     Southeastern Wisconsin Till Plains
              > 54     Central Corn Belt Plains
              > 55     Eastern Corn Belt Plains
              > 56     Southern Michigan/Northern Indiana Drift Plains
              > 57     Huron/Erie Lake Plains
              > 58     Northeastern Highlands
              > 59     Northeastern Coastal Zone
              > 60     Northern Appalachian Plateau and Uplands
              > 61     Erie Drift Plain
              > 62     North Central Appalachians
              > 63     Middle Atlantic Coastal Plain
              > 64     Northern Piedmont
              > 65     Southeastern Plains
              > 66     Blue Ridge
              > 67     Ridge and Valley
              > 68     Southwestern Appalachians
              > 69     Central Appalachians
              > 70     Western Allegheny Plateau
              > 71     Interior Plateau
              > 72     Interior River Valleys and Hills
              > 73     Mississippi Alluvial Plain
              > 74     Mississippi Valley Loess Plains
              > 75     Southern Coastal Plain
              > 76     Southern Florida Coastal Plain
              > 77     North Cascades
              > 78     Klamath Mountains
              > 79     Madrean Archipelago
              > 80     Northern Basin and Range
              > 81     Sonoran Basin and Range
              > 82     Laurentian Plains and Hills
              > 83     Eastern Great Lakes and Hudson Lowlands
              > 84     Atlantic Coastal Pine Barrens
              > 101    Arctic Coastal Plain
              > 102    Arctic Foothills
              > 103    Brooks Range
              > 104    Interior Forested Lowlands And Uplands
              > 105    Interior Highlands
              > 106    Interior Bottomlands
              > 107    Yukon Flats
              > 108    Ogilvie Mountains
              > 109    Subarctic Coastal Plains
              > 110    Seward Peninsula
              > 111    Ahklun And Kilbuck Mountains
              > 112    Bristol Bay-Nushagak Lowlands
              > 113    Alaska Peninsula Mountains
              > 114    Aleutian Islands
              > 115    Cook Inlet
              > 116    Alaska Range
              > 117    Copper Plateau
              > 119    Pacific Coastal Mountains
              > 120    Coastal Western Hemlock-Sitka Spruce Forests
            Enumerated_Domain_Value_Definition_Source: U.S. Environmental Protection Agency

  Distribution_Information:
    Distributor:
      Contact_Information:
        Contact_Organization_Primary:
          Contact_Organization: Earth Science Information Center, U.S. Geological Survey
        Contact_Address:
          Address_Type: Mailing address
          Address: 507 National Center
          City: Reston
          State_or_Province: VA
          Postal_Code: 20192
        Contact_Voice_Telephone: 1-888-ASK-USGS (1-888-275-8747)
        Contact_Voice_Telephone: 703-648-5920
        Contact_Instructions:
          In addition to the address above there are other ESIC offices throughout
          the country. A full list of these offices is at
          <http://ask.usgs.gov/esic_index.html>.
    Distribution_Liability:
      Although these data have been processed successfully on a computer system at
      the U.S. Geological Survey, no warranty expressed or implied is made by the
      U.S. Geological Survey regarding the utility of the data on any other
      system, nor shall the act of distribution constitute any such warranty.  No
      responsibility is assumed by the U.S. Geological Survey in the use of these
      data.

    Standard_Order_Process:
      Digital_Form:
        Digital_Transfer_Information:
          Format_Name: ESRI Shapefile
        Digital_Transfer_Option:
          Online_Option:
            Computer_Contact_Information:
              Network_Address:
                Network_Resource_Name: <http://nationalatlas.gov/atlasftp.html?openChapters=chpbio#chpbio>
      Digital_Form:
        Digital_Transfer_Information:
          Format_Name: SDTS
        Digital_Transfer_Option:
          Online_Option:
            Computer_Contact_Information:
              Network_Address:
                Network_Resource_Name: <http://nationalatlas.gov/atlasftp.html?openChapters=chpbio#chpbio>

      Fees: There is no charge for this map layer.

  Metadata_Reference_Information:
    Metadata_Date: 20060419
    Metadata_Contact:
      Contact_Information:
        Contact_Person_Primary:
          Contact_Person: Peg Rawson
          Contact_Organization: National Atlas of the United States
        Contact_Address:
          Address_Type: Mailing address
          Address: 12201 Sunrise Valley Drive
          Address: MS-561
          City: Reston
          State_or_Province: VA
          Postal_Code: 20192
        Contact_Voice_Telephone: 703-648-4183
        Contact_Electronic_Mail_Address: atlasmail@usgs.gov
    Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
    Metadata_Standard_Version: FGDC-STD-001-1998
    Metadata_Security_Information:
      Metadata_Security_Classification_System: None
      Metadata_Security_Classification: Unclassified
      Metadata_Security_Handling_Description: None