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1:1,000,000-Scale Waterbodies of the United States

Metadata also available as [Parsable text] - [XML]

Frequently anticipated questions:


What does this data set describe?

Title: 1:1,000,000-Scale Waterbodies of the United States
Abstract:
This map layer contains waterbodies of the United States, Puerto Rico, and the U.S. Virgin Islands. The map layer was produced from the medium-resolution National Hydrography Dataset waterbody feature class, through feature selection and cartographic generalization, based on reference to published small-scale ancillary data sets.
  1. How should this data set be cited?

    National Atlas of the United States, 201207, 1:1,000,000-Scale Waterbodies of the United States: National Atlas of the United States, Rolla, MO.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -168
    East_Bounding_Coordinate: -65
    North_Bounding_Coordinate: 72
    South_Bounding_Coordinate: 17

  3. What does it look like?

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

    Calendar_Date: Jul-2012
    Currentness_Reference: Publication 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 (26871)

    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 0.000150. Longitudes are given to the nearest 0.000150. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

  7. How does the data set describe geographic features?

    Waterbody
    An areal water feature. (Source: National Atlas of the United States)

    Waterbdyid
    The unique identifier for the feature. (Source: National Atlas of the United States)

    Range of values
    Minimum:1000001
    Maximum:1026871

    Name
    The proper name of the waterbody. (Source: National Atlas of the United States)

    ValueDefinition
    <blank>The name is unknown, or the feature represents two or more waterbodies that have been merged.

    There is no predefined set of valid waterbody names. Most names come from the Geographic Names Information System.

    Feature
    The type of waterbody. (Source: National Atlas of the United States)

    ValueDefinition
    CanalAn artificial open waterway constructed to transport water, to irrigate or drain land, to connect two or more bodies of water, or to serve as a waterway for water craft.
    GlacierA field of ice.
    LakeA standing body of water with a predominately natural shoreline surrounded by land.
    Lake DryAn area that at one time contained a standing body of water.
    Lake IntermittentA standing body of water that contains water for only part of the year.
    ReservoirA constructed basin formed to contain water.
    StreamA body of flowing water.
    Swamp or MarshA non-cultivated, vegetated area that is inundated or saturated for a significant part of the year.

    F_Code
    A numeric code indicating the type of waterbody described by the feature label. (Source: National Atlas of the United States)

    ValueDefinition
    1Lake
    2Reservoir
    4Stream
    5Canal
    7Glacier
    10Lake Dry
    11Lake Intermittent
    26Swamp or Marsh

    State
    The 2-letter Federal Information Processing Standard (FIPS) code for the State or State equivalent in which the waterbody is located. If the waterbody falls in multiple States, multiple State codes are listed, separated by a dash. (Source: National Atlas of the United States)

    Formal codeset
    Codeset Name: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.
    Codeset Source:U.S. Department of Commerce

    State_FIPS
    The 2-digit FIPS code for the State or State equivalent in which the waterbody is located. If the waterbody falls in multiple States, multiple codes are listed, separated by a dash. (Source: National Atlas of the United States)

    Formal codeset
    Codeset Name: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.
    Codeset Source:U.S. Department of Commerce

    Region
    The hydrologic unit code for the major river basin in which the waterbody is located. Leading zeroes are not shown. If the waterbody falls in two regions, the code for the region containing the majority of the waterbody is used. (Source: National Atlas of the United States)

    Range of values
    Minimum:1
    Maximum:21

    Perim_mi
    The length of the waterbody perimeter in miles, calculated using the North America Albers Equal Area Conic projection. (Source: National Atlas of the United States)

    Range of values
    Minimum:0.24455447440
    Maximum:5844.09486609000

    Area_mi
    The area of the waterbody in square miles, calculated using the North America Albers Equal Area Conic projection. (Source: National Atlas of the United States)

    Range of values
    Minimum:0.00282465086
    Maximum:20459.238446200000

    GM_f_code
    Global Map FACC feature code (Source: Global Map Specifications Version 2.1)

    ValueDefinition
    BH000Any known inland waterway body, such as: lake/pond, reservoir, river/stream, etc. requiring separation into individual features due to status/type grouping that is currently indeterminable.

    Gm_hyc
    Global Map Hydrological category (Source: Global Map Specifications Version 2.1)

    ValueDefinition
    6Non-perennial/Intermittent/Fluctuating
    8Perennial/Permanent

    GM_hyt
    Global Map Hydrological type (Source: Global Map Specifications Version 2.1)

    ValueDefinition
    0Unknown
    1River
    4Lake
    10Reservoir
    13Swamp or Marsh
    16Glacier

    Gm_nam
    The Global Map name, which is the proper name of the feature. (Source: National Atlas of the United States)

    ValueDefinition
    UNKThe name is unknown.

    There is no predefined set of valid feature names.

    Gm_soc
    Global Map Source country (Source: Global Map Specifications Version 2.1)

    ValueDefinition
    USAUnited States of America


Who produced the data set?

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

    • National Atlas of the United States

  2. Who also contributed to the data set?

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

    National Atlas of the United States
    U.S. Geological Survey
    Reston, VA 20192

    1-888-ASK-USGS (1-888-275-8747) (voice)
    atlasmail@usgs.gov

    Contact_Instructions:
    For questions about this map layer or metadata, please contact the National Atlas using the information above, or through the U.S. Geological Survey contact page at <http://www.usgs.gov/ask/>. For distribution questions, please see the Distribution Information elsewhere in this metadata.


Why was the data set created?

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 1:1,000,000-scale data. No responsibility is assumed by the National Atlas of the United States in the use of these data.


How was the data set created?

  1. From what previous works were the data drawn?

    NHD Waterbody 1:100K (source 1 of 28)
    U.S. Geological Survey, 1999, National Hydrography Dataset Waterbody: U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: Online
    Source_Scale_Denominator: 100000
    Source_Contribution:
    Spatial and attribute information. Served as the primary source data from which the 1:1,000,000-scale map layer was created.

    National Atlas Waterbodies 1:2M (source 2 of 28)
    National Atlas of the United States, 200512, Streams and Waterbodies of the United States: National Atlas of the United States, Reston, VA.

    Online Links:

    Type_of_Source_Media: Online
    Source_Scale_Denominator: 2000000
    Source_Contribution:
    Spatial and attribute information. Used to identify additional features to include in the map layer.

    National Atlas Streams 1:1M (source 3 of 28)
    National Atlas of the United States, 201207, 1:1,000,000-Scale Streams and Rivers of the United States.

    Online Links:

    Type_of_Source_Media: Online
    Source_Scale_Denominator: 1000000
    Source_Contribution:
    Spatial information. Used as a guide to determine the location and extent of waterbody limits during manual generalization processes.

    National Atlas Coastline 1:1M (source 4 of 28)
    National Atlas of the United States, 201207, 1:1,000,000-Scale Coastlines of the United States.

    Online Links:

    Type_of_Source_Media: Online
    Source_Scale_Denominator: 1000000
    Source_Contribution:
    Spatial and attribute information. The coastlines were used as the limit for waterbodies bordering the ocean or Great Lakes. They were also used as the source for the shoreline of the Great Lakes.

    ESRI Imagery World 2D (source 5 of 28)
    Environmental Systems Research Institute - ESRI, 2009, ESRI Imagery World 2D Map Service.

    Online Links:

    Type_of_Source_Media: Online
    Source_Contribution: Spatial and attribute information.

    NLCD 2001 Image Service (source 6 of 28)
    Multi-Resolution Land Characteristics Consortium, 2004, National Land Cover Database 2001.

    Online Links:

    Type_of_Source_Media: Online
    Source_Contribution: Spatial and attribute information.

    NHDPlus Waterbody 1:100K (source 7 of 28)
    U.S. Environmental Protection Agency (USEPA), and U.S. Geological Survey (USGS), 2005, National Hydrography Dataset Plus Waterbody.

    Online Links:

    Type_of_Source_Media: Online
    Source_Scale_Denominator: 100000
    Source_Contribution:
    Spatial information. Used as a guide to determine the location and extent of waterbodies during manual generalization and aggregation processes.

    NHDPlus Area 1:100K (source 8 of 28)
    U.S. Environmental Protection Agency (USEPA), and U.S. Geological Survey (USGS), 2005, National Hydrography Dataset Plus Area.

    Online Links:

    Type_of_Source_Media: online
    Source_Scale_Denominator: 100000
    Source_Contribution:
    Spatial information. Used as a guide to determine the location and extent of waterbodies during manual generalization and aggregation processes.

    USA Topo Maps Map Service (source 9 of 28)
    Environmental Systems Research Institute - ESRI, 2009, ESRI USA Topo Maps Map Service.

    Online Links:

    Type_of_Source_Media: Online
    Source_Contribution: Spatial and attribute information.

    National Atlas National Boundaries 1:1M (source 10 of 28)
    National Atlas of the United States, 201207, 1:1,000,000-Scale National Boundaries of the United States.

    Online Links:

    Type_of_Source_Media: Online
    Source_Scale_Denominator: 1000000
    Source_Contribution:
    Spatial information. The national boundary was used to delimit waterbodies that intersect the borders of Canada and Mexico.

    State Base Maps 1:500K (source 11 of 28)
    U.S. Geological Survey, Unknown, 1:500,000-scale State Base Map Series.

    Type_of_Source_Media: Paper
    Source_Scale_Denominator: 500000
    Source_Contribution: Spatial and attribute information.

    Paper Topo Maps 1:24K (source 12 of 28)
    U.S. Geological Survey, Unknown, 1:24,000-scale Topographic Map Series.

    Type_of_Source_Media: Paper
    Source_Scale_Denominator: 24000
    Source_Contribution: Spatial and attribute information.

    Paper Topo Maps 1:63,360 (source 13 of 28)
    U.S. Geological Survey, Unknown, 1:63,360-scale Topographic Map Series.

    Type_of_Source_Media: Paper
    Source_Scale_Denominator: 63360
    Source_Contribution: Spatial and attribute information.

    Paper Topo Maps 1:100K (source 14 of 28)
    U.S. Geological Survey, Unknown, 1:100,000-scale Topographic Map Series.

    Type_of_Source_Media: Paper
    Source_Scale_Denominator: 100000
    Source_Contribution: Spatial and attribute information.

    Paper Topo Maps 1:250K (source 15 of 28)
    U.S. Geological Survey, Unknown, 1:250,000-scale Topographic Map Series.

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

    National Forest Maps (source 16 of 28)
    U.S. Forest Service, Unknown, National Forest Maps.

    Type_of_Source_Media: Paper
    Source_Contribution: Spatial and attribute information.

    National Atlas Sectional Maps 1:2M (source 17 of 28)
    National Atlas of the United States, Unknown, Sectional Maps.

    Type_of_Source_Media: Paper
    Source_Scale_Denominator: 2000000
    Source_Contribution: Spatial and attribute information.

    State Base Maps 1:1M (source 18 of 28)
    U.S. Geological Survey, Unknown, 1:1,000,000-Scale State Base Map Series.

    Type_of_Source_Media: Paper
    Source_Scale_Denominator: 1000000
    Source_Contribution: Spatial and attribute information.

    Alaska State Base Map (source 19 of 28)
    U.S. Geological Survey, Unknown, Alaska State Base Map.

    Type_of_Source_Media: Paper
    Source_Contribution: Spatial and attribute information.

    Official State Highway Maps (source 20 of 28)
    Departments, State Transportation , Unknown, (variable) Official State Highway Maps.

    Type_of_Source_Media: Paper
    Source_Contribution: Spatial and attribute information.

    Google Maps (source 21 of 28)
    Google, Unknown, Google Maps.

    Online Links:

    Type_of_Source_Media: Online
    Source_Contribution: Spatial and attribute information.

    Google Earth (source 22 of 28)
    Google, Unknown, Google Earth.

    Online Links:

    Type_of_Source_Media: Online
    Source_Contribution: Spatial and attribute information.

    National Atlas Roads 1:1M (source 23 of 28)
    National Atlas of the United States, 201207, 1:1,000,000-Scale Major Roads of the United States.

    Online Links:

    Type_of_Source_Media: Online
    Source_Scale_Denominator: 1000000
    Source_Contribution:
    Spatial information. Waterbody limits were offset from roads if the limit of the waterbody was parallel to the road and within 300 meters of the road.

    National Atlas Railroads 1:1M (source 24 of 28)
    National Atlas of the United States, 201207, 1:1,000,000-Scale Railroads of the United States.

    Online Links:

    Type_of_Source_Media: Online
    Source_Scale_Denominator: 1000000
    Source_Contribution:
    Spatial information. Waterbody limits were offset from railroads if the limit of the waterbody was parallel to the railroad and within 300 meters of the railroad.

    National Atlas Counties 1:1M (source 25 of 28)
    National Atlas of the United States, 201207, 1:1,000,000-Scale County Boundaries of the United States.

    Online Links:

    Type_of_Source_Media: Online
    Source_Scale_Denominator: 1000000
    Source_Contribution:
    Spatial information. Used to determine the location of waterbody limits that are coincident with county boundaries.

    National Atlas States 1:1M (source 26 of 28)
    National Atlas of the United States, 201207, 1:1,000,000-Scale State Boundaries of the United States.

    Online Links:

    Type_of_Source_Media: Online
    Source_Scale_Denominator: 1000000
    Source_Contribution:
    Attribute information. Used to determine the State code and FIPS code.

    National Atlas Hydrologic Units 1:2M (source 27 of 28)
    U.S. Geological Survey, 200506, 1:2,000,000-Scale Hydrologic Unit Boundaries: National Atlas of the United States, Reston, VA.

    Online Links:

    Type_of_Source_Media: Online
    Source_Scale_Denominator: 2000000
    Source_Contribution:
    Attribute information. Used to determine which region a waterbody belonged in if it crossed regional boundaries.

    Global Map Specifications Version 2.1 (source 28 of 28)
    International Steering Committee for Global Mapping, 2011, Global Map Specifications Version 2.1.

    Type_of_Source_Media: Online
    Source_Contribution:
    Attribute information. Used to define the Global Map attributes and determine their values.

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

    Date: 2007 (process 1 of 21)
    Feature Selection
    Waterbodies with an area greater than 1.0 square kilometer were selected from the NHD Waterbody 100K data set. Waterbodies between 0.5625 square kilometers and 1 square kilometer were selected from the NHD Waterbody 100K data set if there was a corresponding waterbody represented by the National Atlas Waterbodies 1:2M map layer.

    Data sources used in this process:

    • NHD Waterbody 1:100K
    • National Atlas Waterbodies 1:2M

    Date: 2007 (process 2 of 21)
    Cartographic Generalization - Phase 1
    All waterbodies selected in the feature-selection process were exported as a new feature class, then simplified using the Bend Simplify algorithm with a tolerance of 500 meters. The feature class was further simplified using the Douglas-Peucker algorithm with a 1- meter tolerance to remove extraneous vertices. The new, simplified and generalized data set was checked for multipart features, overlaps, and gaps. Topology errors were corrected.

    Date: 2007 (process 3 of 21)
    Calculation of Feature types
    The Feature attribute describes the type of waterbody. The set of feature types comes from the National Atlas Waterbodies 1:2M map layer. The Feature attribute value for each waterbody was calculated based on the NHD Fcode, using the following crosswalk:
    Lake: NHD FCode is 39000, 39004, 39009, 39010, 39011, or 39012.
    Lake Dry: NHD FCode is 36100.
    Lake Intermittent: NHD FCode is 39001, 39005, or 39006.
    Reservoir: NHD FCode starts with 436.
    Swamp or Marsh: NHD FCode is 46600.
    Glacier: NHD FCode is 37800.
    Stream: NHD FCode is 46006 (perennial), 46003 (intermittent), or
            46000 (no info).
    Canal: Added manually
    

    Data sources used in this process:

    • National Atlas Waterbodies 1:2M
    • NHD Waterbody 1:100K

    Date: 2007 (process 4 of 21)
    Calculation of F_Code
    The F_code is a numeric code indicating the type of water feature described by the feature label. The set of F_codes comes from the National Atlas Waterbodies 1:2M map layer. The following crosswalk was used to create F_codes from the Feature values.
    F_code    Feature value
    -----------------------------
    1	   Lake
    2	   Reservoir
    4	   Stream
    5	   Canal
    7 	   Glacier
    10 	   Lake Dry
    11 	   Lake Intermittent
    26	   Swamp or Marsh
    

    Data sources used in this process:

    • National Atlas Waterbodies 1:2M

    Date: 2009 (process 5 of 21)
    Addition of River Polygons
    Polygons representing major rivers were added from the National Atlas Waterbodies 1:2M dataset and aligned with imagery and existing 1:1M waterbodies.

    Data sources used in this process:

    • National Atlas Waterbodies 1:2M
    • ESRI Imagery World 2D

    Date: 2009 (process 6 of 21)
    Integration of Waterbodies with 1:1M Streams
    During the generalization process, waterbodies sometimes became misaligned with the streams that flow through them. The streams and waterbody limits were corrected so that the streams flow through the waterbodies. The waterbody types included in the alignment process were lake, lake dry, lake intermittent, reservoir, and stream. No realignment was done for swamp or marsh.

    Data sources used in this process:

    • National Atlas Streams 1:1M

    Date: 2009 (process 7 of 21)
    Integration of Waterbodies with 1:1M Coastlines
    Waterbodies were clipped or extended to the 1:1M Coastline. Aerial imagery, land cover, NHDPlus Waterbody, NHDPlus Area, and topographical maps were used to determine where the limits of waterbodies should coincide with the coastline. Swamp or Marsh waterbodies were created for islands that were predominantly wetlands. To ensure alignment of waterbodies and coastlines, the data were checked for topological consistency using ArcGIS.

    Data sources used in this process:

    • National Atlas Coastline 1:1M
    • ESRI Imagery World 2D
    • NLCD 2001 Image Service
    • NHDPlus Waterbody 1:100K
    • NHDPlus Area 1:100K
    • USA Topo Maps Map Service

    Date: 2009 (process 8 of 21)
    Elimination of Small Islands and Gaps Within and Between Waterbodies
    The 1 square kilometer size threshold for waterbodies eliminated many small waterbodies that were completely surrounded by larger waterbodies (usually a lake within a wetland). This left holes in the waterbodies. There were also gaps between waterbodies and islands within waterbodies, some of which were too small for the scale of the map layer. Polygons were created for the small holes and gaps and merged with the surrounding waterbodies.

    Data sources used in this process:

    • USA Topo Maps Map Service

    Date: 2010 (process 9 of 21)
    Cartographic Generalization - Phase 2
    A second phase of generalization was needed to address the width of waterbodies and the distance between waterbodies. It was determined that a minimum waterbody width of 500 meters was appropriate for this scale. Sections of a waterbody that were as narrow as 300 meters were acceptable if they connected wider areas or if they were the tapered end of a waterbody.
    The Buffer tool was used with a series of negative and positive buffer distances to create two sets of interior polygons for the waterbodies, one set representing the parts of the waterbodies that were at least 300 meters wide, and another set representing the parts of the waterbodies that were at least 500 meters wide. The waterbodies were then edited manually using the interior polygons as guidelines and using imagery, land cover, NHDPlus Waterbody, NHDPlus Area, and topographical maps to support decisions. Some features were eliminated based on width. Other features were trimmed, widened, or merged with neighboring features.
    The minimum acceptable distance between waterbodies was 300 meters.  A set of exterior buffers 150 meters wide was created from the waterbodies.  If the exterior buffer of one feature overlapped that of another, the two features were separated or merged, or they were modified so that they shared a common limit. Imagery, land cover, NHDPlus Waterbody, NHDPlus Area, and topographical maps were used to support decisions.

    Data sources used in this process:

    • National Atlas Waterbodies 1:2M
    • ESRI Imagery World 2D
    • NLCD 2001 Image Service
    • NHDPlus Waterbody 1:100K
    • NHDPlus Area 1:100K
    • USA Topo Maps Map Service

    Date: 2010 (process 10 of 21)
    Addition of the Great Lakes
    A Great Lakes polygon was created with the 1:1M coastline as the southern limit and the 1:1M national boundary between the United States and Canada as the northern limit. The resulting polygon was then divided into Lake Superior, Lake Michigan, Lake Huron, Lake Erie, Lake Ontario and smaller adjacent lakes, bays, and rivers.

    Data sources used in this process:

    • National Atlas Coastline 1:1M
    • National Atlas National Boundaries 1:1M

    Date: 2010 (process 11 of 21)
    Cartographic Review - Phase 1
    Cartographers reviewed waterbodies by comparing them to existing small scale datasets, imagery, and maps. The name, location, extent and feature type were examined and recommendations for deletions, modifications, and additions were incorporated.

    Data sources used in this process:

    • NLCD 2001 Image Service
    • USA Topo Maps Map Service
    • ESRI Imagery World 2D
    • State Base Maps 1:500K
    • Paper Topo Maps 1:24K
    • Paper Topo Maps 1:63,360
    • Paper Topo Maps 1:100K
    • Paper Topo Maps 1:250K
    • National Forest Maps
    • National Atlas Sectional Maps 1:2M
    • State Base Maps 1:1M
    • Alaska State Base Map
    • Official State Highway Maps
    • Google Maps
    • Google Earth

    Date: 2011 (process 12 of 21)
    Integration of Waterbodies with 1:1M National Boundaries
    Waterbodies were clipped or extended to 1:1M National Boundaries. To ensure alignment, the data were checked for topological consistency using ArcGIS.

    Data sources used in this process:

    • National Atlas National Boundaries 1:1M

    Date: 2011 (process 13 of 21)
    Integration of Waterbodies with 1:1M Transportation Features
    Waterbody limits that were parallel to transportation features in the National Atlas 1:1M Roads and Railroads were moved away from the transportation features to ensure that there was a 300 meter gap between the two types of features.

    Data sources used in this process:

    • National Atlas Roads 1:1M
    • National Atlas Railroads 1:1M

    Date: 2011 (process 14 of 21)
    Cartographic Review - Phase 2
    National Atlas 1:1,000,000-scale map layers were reviewed together to check for features that needed to be added, deleted, or modified, and to determine if the distances between features were appropriate for the product scale.

    Data sources used in this process:

    • National Atlas Coastline 1:1M
    • National Atlas National Boundaries 1:1M
    • National Atlas Roads 1:1M
    • National Atlas Railroads 1:1M
    • National Atlas Streams 1:1M
    • National Atlas Counties 1:1M

    Date: 2011 (process 15 of 21)
    Integration of Waterbodies with 1:1M Counties
    Waterbodies that have limit on a county line were aligned with the county line so that the two are coincident.

    Data sources used in this process:

    • National Atlas Counties 1:1M
    • USA Topo Maps Map Service
    • ESRI Imagery World 2D

    Date: 2012 (process 16 of 21)
    Calculation of WaterbdyID
    The WaterbdyID is the unique identifier for the features. The starting number is 1,000,001.

    Date: 2012 (process 17 of 21)
    Calculation of Name
    The name of the waterbody generally comes from the GNIS_Name attribute in NHDPlus Waterbody 1:100K. Some waterbodies without names were identified manually if they intersected a waterbody in the National Atlas Waterbodies 1:2M file. Additional waterbody names were selected manually based on waterbody names on other small scale maps. If two named waterbodies were merged, the name attribute was changed to null.

    Data sources used in this process:

    • NHDPlus Waterbody 1:100K
    • National Atlas Waterbodies 1:2M
    • USA Topo Maps Map Service
    • State Base Maps 1:500K
    • Paper Topo Maps 1:24K
    • Paper Topo Maps 1:63,360
    • Paper Topo Maps 1:100K
    • Paper Topo Maps 1:250K
    • National Forest Maps
    • National Atlas Sectional Maps 1:2M
    • State Base Maps 1:1M
    • Alaska State Base Map
    • Official State Highway Maps
    • Google Maps

    Date: 2012 (process 18 of 21)
    Calculation of State Abbreviation and FIPS codes
    The waterbodies were intersected with the National Atlas States 1:1M map layer to transfer the State abbreviations and FIPS codes. The intersected layer was analyzed to determine which waterbodies corresponded to multiple States. For features crossing State boundaries, the State abbreviations and FIPS codes were concatenated with a hyphen to include information from multiple States.

    Data sources used in this process:

    • National Atlas States 1:1M

    Date: 2012 (process 19 of 21)
    Calculation of Region
    The two-digit Hydrologic Unit Code was calculated from the four-digit NHD Waterbody Subregion code. Waterbodies were also checked against the National Atlas Hydrologic Units. In cases where a waterbody was in two regions, the code for the region containing the majority of the waterbody was used.

    Data sources used in this process:

    • NHDPlus Waterbody 1:100K
    • National Atlas Hydrologic Units 1:2M

    Date: 2012 (process 20 of 21)
    Calculation of Perimeter and Area
    The data were converted to a North America Albers Equal Area Conic projection. Perimeter in miles and area in square miles were calculated, then the data were converted back to geographics.

    Date: 2012 (process 21 of 21)
    Calculation of Global Map Attributes
    The attributes GM_f_code, GM_hyc, GM_hyt, GM_nam, and GM_soc are attributes for Global Map. They facilitate the use of National Atlas 1:1,000,000-scale data with other nations' Global Map data. GM_f_code, GM_hyc, and GM_hyt were calculated based on the Feature attribute. GM_nam was calculated from the Name attribute. GM_soc is the abbreviation for the United States listed in the Global Map Specifications Version 2.1.

    Data sources used in this process:

    • Global Map Specifications 2.1

  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?

    All attributes were checked to make sure their values are in the correct domains. No null (blank) values are present except in the Name attribute.
    The WaterbdyID was checked for duplicates and nulls. All features have a unique WaterbdyID.
    Names come from Geographic Names Information System (GNIS) names in the National Hydrography Dataset (NHD) 100K waterbodies. Additional names were added manually based on information from other maps and data sets. They were reordered so that the generic feature type such as "Lake", "River", "Glacier", etc. was in the correct position for a label. They were checked for invalid characters and foreign characters. Waterbodies with no name have a null value.
    Selections by attribute and location were used to ensure the Region attribute matches the region the waterbody is in.
    Perimeter in miles and area in square miles were calculated using the North America Albers Equal Area Conic projection. Features have been generalized and aggregated so their measurements may be different from a measurement in a larger-scale data set.

  2. How accurate are the geographic locations?

    Waterbodies are in approximately the same locations as in the NHD 100K waterbodies data used as a source. However, many processes and editing tasks resulted in the movement of waterbody limits from their original positions, including: generalizing and aggregating waterbodies, modifying waterbodies to meet minimum width standards, moving waterbody limits 300 meters from transportation features if the two were parallel, extending or trimming waterbodies to intersect coastlines or international boundaries, increasing or decreasing the gap between neighboring waterbodies, adjusting waterbodies to fit the streams that flow through them, and modifying waterbodies to match imagery.

  3. How accurate are the heights or depths?

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

    This map layer contains waterbodies of the United States, Puerto Rico, and the U.S. Virgin Islands. Only waterbodies appropriate for a 1:1,000,000- scale data set are included. Waterbodies smaller than one square kilometer are excluded unless one of the following applies: they are in the National Atlas 1:2,000,000-scale map layer, they are in other small- scale data sets or maps, they cover a small coastal island, they have been merged with a larger feature, or their size has been reduced during alignment with other 1:1,000,000-scale map layers.
    Swamps and marshes may be underrepresented in some areas. In the southeastern U.S. some swamp/marsh limits were difficult to determine due to unclear or conflicting information in imagery, topographical maps, and landcover. In Alaska, swamps and marshes appear to be underrepresented when compared to land cover data sets and topographical maps.
    Waterbodies may also be underrepresented in areas that contain large numbers of small isolated features which were too far apart to aggregate and too small to be included by themselves.

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

    Waterbodies were checked for topological consistency using ArcGIS, to ensure there were no overlapping waterbodies or small gaps between waterbodies. The topology rules were also used to check the alignment of waterbodies with coastlines and international borders. Multi-part features were divided into separate waterbodies. Waterbodies were compared to aerial imagery to verify location and extent.


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 National Atlas of the United States of America would be appreciated in products derived from these data.

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

    Earth Explorer, U.S. Geological Survey
    U.S. Geological Survey
    Sioux Falls, SD 57198-0001

    605-594-6116 (voice)
    lpdaac@usgs.gov

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

  3. What legal disclaimers am I supposed to read?

    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.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 24-Jul-2012
Metadata author:
National Atlas of the United States
U.S. Geological Survey
Reston, VA 20192

1-888-ASK-USGS (1-888-275-8747) (voice)
atlasmail@usgs.gov

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



 


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