National Atlas FAQ

• What are the National Atlas Layers?
• What are the specifications of the National Atlas Layers?
• What formats are available?
• What is the coverage area?
• How many layers are available?
• Where can more information be found about National Atlas?

Q. What are the National Atlas Layers?

A. The Atlas layers consist of a reliable summary of national-scale geographical information. The data source is National Atlas of the United States®. The National Atlas of the United States® is intended to provide a comprehensive, map-like view into the enormous wealth of data collected by the Federal Government.

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Q.What are the specifications of the National Atlas Layers?

A.

Product	Projection	Horizontal Datum	Vertical Datum
National Atlas Layers	Geographic	NAD83	NAVD88

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Q. What formats are available?

A. The only format available for National Atlas layers is Shapefiles. Shapefile is format for storing the location, shape, and attribute information of geographic features. Technical information about shapefiles can be found at: http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf

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Q. What is the coverage area?

A. Most of the coverage areas are for the conterminous US. Depending on the actual layer coverage may vary.

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Q. How many layers are available?

A. When all of the National Atlas layers have been added to The National Map Seamless Server, there will be approximately 80 layers.

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Q. Where can more information be found about National Atlas?

A. The source of the National Atlas is the website http://www.nationalatlas.gov/

Also, there is a list of FAQ's on the National Atlas website at: http://nationalatlas.gov/faq.html

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