What is 1?
It's the set of digital cartographic frameworks
from The National Atlas of the United States of America® at a
scale of 1:1,000,000.
It also includes national
images of elevation, land cover, and Landsat at 100-meter ground resolution.
How do I get 1?
Go to nationalatlas.gov and follow the path for
Mapping Professionals to get 1 via file transfer
protocol or to use 1 as a Web Service. Our
Web Map Services and Web Feature Services comply with the latest specifications
the Open Geospatial Consortium.
How much do you charge for 1?
1 is provided on-line at no cost to the end user.
Why did you switch from two million- to one
1 delivers more content and a greater level of detail.
It allows us to harmonize authoritative small-scale
base data from the United States with similar data
from Canada and Mexico. 1 also delivers the
United States contribution to the international
Global Map effort.
Is the two million-scale data still available?
Yes, but 1 is replacing it.
We don't plan to revise the two million-scale frameworks.
What's this Global Map edition of 1?
More than 100 national mapping organizations join
together to produce consistent data of the world at
one million-scale. 1 is the American contribution
from the National Atlas to the international
Global Map effort. The spatial data in all editions is the
same, but data attributes in this edition conform to
the latest Global Map data model and specification.
What file formats can we expect?
We introduced 1 in industry standard
shapefile format. Geodatabase and GeoTIFF formats were introduced in April 2013. U.S. Geological Survey
managers have decided to end the National Atlas on September 30, 2014, and no additional formats will be offered.
What do you mean by "networked hydrography?"
America's surface waters are being delivered in two ways; as a set of national shapefiles and as five fully networked file geodatabases that are built on the National Hydrography Dataset (NHD) model. One of these file geodatabases covers the entire United States while the others contain data for the conterminous United States, Alaska, Hawaii, or Puerto Rico and the U.S. Virgin Islands.
Like the NHD, 1 contains a flow network that allows
for tracing water downstream or upstream. It also
uses an addressing system based on reach codes
and linear referencing you can use to link specific
information such as discharge rates and water quality.
Each Esri file geodatabase includes streams, waterbodies &
wetlands, coastlines, and gaging stations.
Is 1 documented?
Sure it's documented and you can't
from us without getting full, extensive metadata, too.
What's the map projection for
The vector files you download are distributed in the
EPSG:4326 projection. Our Web Map Services are also delivered in EPSG:4326
while our Web Feature Services are delivered in the EPSG:4269 map projection.
Elevation, land cover, and Landsat images at 100-meter
resolution are delivered in the Albers Equal-Area Conic map projection.