Data

EROS has digitized over 6.4 million frames of aerial film creating medium-resolution digital images (400dpi) and associated browse images for on-line viewing. Products can be downloaded at no cost through EarthExplorer or GloVis. 
Simply defined, scale can be expressed as the ratio or proportion between a distance on the aerial photographs (or maps) and the actual distance on the ground or land surface. It is a ratio that could represent any unit of measurement and this ratio is...
A feature is something shown on a map, and it has characteristics or properties, which can be represented in feature-based Digital Line Graph (DLG) data using attributes and values.
The Geographic Names Information System (GNIS), developed by the U.S. Geological Survey (USGS) in cooperation with the U.S. Board on Geographic Names (BGN), contains information about the official names for places, features, and areas in the 50 States,...
Yes.  Scanning of the EROS film archives is following a plan to capture images from rolls at risk of decay from vinegar syndrome. Science requirements are also reviewed on a regular basis, but a formal, on-line schedule is not available at this time....
The Columbia River is the largest river in the Pacific Northwest and, with a length of 1,953 kilometers (1,214 miles), is the 15th longest in North America. From its source at Columbia Lake at an elevation of 809 meters (2,650 feet) in Canada's Selkirk...