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2014. Wessel, Paul and Smith, Walter H. F. This polygon shapefile represents the boundary between lake islands and lakes at crude resolution. Lake islands, or inland islands, are landmasses ... United States. National Geospatial-Intelligence Agency.
2010. National Geophysical Data Center. This line shapefile shows lines of equal annual change (secular variation) in the horizontal component of the total field intensity of the Earth's ... National Atlas of the United States.
2004. Instituto Nacional de Estadística, Geografía e Informática (Mexico), Geological Survey (U.S.), and Canada Centre for Remote Sensing. This polygon shapefile depicts the political boundaries of North America, including: international boundaries, provincial boundaries, state or terr... Geological Survey (U.S.).
2010. National Geophysical Data Center. This shapefile shows isoclinic lines (lines of constant inclination of the Earth's magnetic field), derived from the International Geomagnetic Refe... National Atlas of the United States.
2010. National Geophysical Data Center. This map layer shows isoporic lines (lines of equal annual change, or secular variation, in the declination of the Earth's magnetic field), derived... National Atlas of the United States.
2010. National Geophysical Data Center. This line shapefile shows lines of equal horizontal intensity of the Earth's magnetic field, derived from the International Geomagnetic Reference F... National Atlas of the United States.
2001. National Atlas of the United States. The Bathymetric Shaded Relief of North America map layer shows depth ranges using colors, with relief enhanced by shading. The image was derived fr... National Atlas of the United States.
2001. National Atlas of the United States. The Bathymetry of North America map layer shows depth ranges using colors. The image was derived from the National Geophysical Data Center's ETOPO2... National Atlas of the United States.
1992. Wade, Tim. This raster layer is a 540 meter resolution grid map of the conterminous United States in GeoTIFF format, created from National Land Cover Data (NL... National Atlas of the United States.
1992 and 1993. Ritters, Kurt. This raster layer is a grid map of North America including the Caribbean and most of Mexico in GeoTIFF format. The map layer is an excerpt from a g... National Atlas of the United States.