This line shapefile shows elevation contour lines for the conterminous United States. The map layer was derived from the 100-meter resolution elevation data set which is published by the National Atlas of the United States, and is in the same Albers Equal-area Conic projection as that source data set. Contour intervals match the steps used in the National Atlas Color-Sliced Elevation data sets. Contours were adjusted so that they are in the proper relationship to National Atlas 1:1,000,000-scale lakes, reservoirs, and wide (double-line) streams. This layer is part of the 1997-2014 edition National Atlas of the United States.
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.