From the U.S. Geological Survey's National Map:
"Bare earth digital elevation model (DEM) data from the NED, previously available through the Seamless Server Viewer, is accessed in The National Map Viewer with the 'Download Data' tool. Use the following procedures to download DEM data:
- Zoom to your area of interest.
- Click the Download Data tool near the top right corner of the viewer banner.
- Use the current map extent, choose a reference area polygon from the Download options dropdown menu, or create your own custom polygon.
- Select the data theme of Elevation and product format.
- Select available NED products, such as 2 arc-second (Alaska only), 1 arc-second (conterminous U.S., Hawaii, Puerto Rico, portions of Alaska, western & southern Canada along U.S. border, and all of Mexico), 1/3 arc-second (conterminous U.S., Hawaii, and portions of Alaska), or 1/9 arc-second (in limited areas of U.S. only).
- Add selected products to the Cart.
- Checkout and enter your e-mail address twice to place your order.
Note that you will not initially see the Elevation theme in The National Map Viewer's Overlays table of contents, although we are working on offering more visualization options in the near future. Also, be aware that NED 1- and 1/3-arc-second elevation products are available only as 'staged' data in pre-packaged 1x1 degree cell extents in either ArcGrid or GridFloat formats, while NED 1/9-arc-second elevation products are currently available through 'dynamic' extracts in user defined reference area polygons with additional formats of GeoTIFF or BIL_16INT (besides ArcGrid or GridFloat)."
Retrieved from the National Map Viewer website on 4/19/13.
