This is a fancy phrase that means "digital map layer." Federal partners produce a wide variety of information and statistics that have a spatial component. That is, the information they collect is keyed to some location (space) in the United States. There are many different types of keys to American locations. Latitude and longitude, state and county boundaries, zip code boundaries, addresses, and the boundaries of Congressional Districts are examples of spatial keys. Any data base with a spatial component can be turned into a map. These digital map layers are available now.

Information about a spatial data base is commonly called "metadata." For each spatial data base (map layer) included in the National Atlas we have produced a separate metadata file. Each metadata file includes information describing the contents of a map layer. Metadata files also include information describing how a map layer was made, its lineage, and its quality.

We've been asking prospective customers to tell us what they expect from a National Atlas. In addition to interactive maps and mapping information, these people have told us that they're interested in learning more about topics that directly affect or contribute to their quality of life. They want their curiosity stimulated and they want the Atlas to raise the standard for the level of information presented and the way it is presented. These folks want a National Atlas that will enhance their knowledge of their place in society. And they want a deeper understanding of how the natural environment affects their choices and fresh insights into changes that humans have made to that environment. We will continue to supplement our cartographic products with well-written, authoritative, and provocative narratives.