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Authoritative

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    The USGS Transportation service from The National Map (TNM) is based on TIGER/Line data provided through U.S. Census Bureau and supplemented with HERE road data to create tile cache base maps. Some of the TIGER/Line data includes limited corrections done by USGS. Transportation data consists of roads, railroads, trails, airports, and other features associated with the transport of people or commerce. The data include the name or route designator, classification, and location. Transportation data support general mapping and geographic information system technology analysis for applications such as traffic safety, congestion mitigation, disaster planning, and emergency response. The National Map transportation data is commonly combined with other data themes, such as boundaries, elevation, hydrography, and structures, to produce general reference base maps. The National Map viewer allows free downloads of public domain transportation data in either Esri File Geodatabase or Shapefile formats. For additional information on the transportation data model, go to http://nationalmap.gov/transport.html.

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    All 1:250,000 NTDB Transportation features including roads, trails, and railways.

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    This map of the first vertical derivative of the magnetic field was derived from data acquired during an aeromagnetic survey carried out by EON Geosciences Inc. in the period between April 10, 2009 and September 16, 2009. The data were recorded using split-beam cesium vapour magnetometers (sensitivity = 0.005 nT) mounted in each of the tail booms of a Piper Navajo and a Cessna 206 aircraft. The nominal traverse and control line spacings were, respectively, 800 m and 2 400 m, and the aircraft flew at a nominal terrain clearance of 250 m. Traverse lines were oriented N90?E with orthogonal control lines. The flight path was recovered following post-flight differential corrections to the raw Global Positioning System data and inspection of ground images recorded by a vertically-mounted video camera. The survey was flown on a pre-determined flight surface to minimize differences in magnetic values at the intersections of control and traverse lines. These differences were computer-analysed to obtain a mutually levelled set of flight-line magnetic data. The levelled values were then interpolated to a 200 m grid. The International Geomagnetic Reference Field (IGRF) was not removed from the total magnetic field.

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    The purpose of this feature class is to identify the forest resources management zones within a Forest Resources Management Plan, as per subsection 2(h) of the Forest Resources Regulation. These sub-divided smaller forest planning areas or landscape units are based on watershed boundaries and modified by local access and development patterns. They usually contain similar management concerns and forest types. The units form the boundaries for detailed information gathering, monitoring and planning.

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    This map of the total magnetic field was derived from data acquired during an aeromagnetic survey carried out by EON Geosciences Inc. in the period between April 10, 2009 and September 16, 2009. The data were recorded using split-beam cesium vapour magnetometers (sensitivity =0.005 nT) mounted in each of the tail booms of a Piper Navajo and a Cessna 206 aircraft. The nominal traverse and control line spacings were, respectively, 800 m and 2 400 m, and the aircraft flew at a nominal terrain clearance of 250 m. Traverse lines were oriented N90?E with orthogonal control lines. The flight path was recovered following post-flight differential corrections to the raw Global Positioning System data and inspection of ground images recorded by a vertically-mounted video camera. The survey was flown on a pre-determined flight surface to minimize differences in magnetic values at the intersections of control and traverse lines. These differences were computer-analysed to obtain a mutually levelled set of flight-line magnetic data. The levelled values were then interpolated to a 200 m grid. The International Geomagnetic Reference Field (IGRF) was not removed from the magnetic field.

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    1:50,000 NTDB Waterbodies - Lakes, Double Line Rivers Based on Edition 2.x.

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    This map of the first vertical derivative of the magnetic field was derived from data acquired during an aeromagnetic survey carried out by EON Geosciences Inc. during the period between April 12, 2010 to June 2, 2010. The data were recorded using a split-beam cesium vapour magnetometer (sensitivity = 0.005 nT) mounted in the tail boom of a Piper Navajo aircraft. The nominal traverse and control line spacings were, respectively, 800 m and 2 400 m, and the aircraft flew at a nominal terrain clearance of 250 m. Traverse lines were oriented N45?E with orthogonal control lines. The flight path was recovered following post-flight differential corrections to the raw Global Positioning System data and inspection of ground images recorded by a vertically-mounted video camera. The survey was flown on a pre-determined flight surface to minimize differences in magnetic values at the intersections of control and traverse lines. These differences were computer-analysed to obtain a mutually levelled set of flight-line magnetic data. The levelled values were then interpolated to a 200 m grid. The International Geomagnetic Reference Field (IGRF) was not removed from the magnetic field.

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    1:250,000 NTDB Waterbodies - Lakes, Double Line rivers

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    Yukon Community points were derived from the CSW_BASE.PLACE_PT_1M data that originally came from the 1:1,000,000 scale Digital Chart of the World dataset. It is derived based on Major Cities and Communities in the Yukon.

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    Features are Administrative Land Objects that represent the spatial extents of a jurisdiction that is created and managed as a separate entity within the ICM database. Un-derived Administrative Areas include QUADs, Groups, Subdivisions, Municipalities, Block Land Transfers, Settlement Areas, Districts and Regions. Un-derived Administrative Areas also include the spatial extent of site that do not have a specific administrative boundary such as Indian settlements and national historic sites. In the LYR files for CSW, the QUADs & Groups were removed with a Querry Builder.