## Lambert azimuthal projection for U.S.

The Lambert azimuthal projection which is widely used by the USGS and
other agencies for the 48 conterminous states is defined as
follows: Projection: Lambert azimuthal
Datum: none
Units: meters
Radius of sphere of reference: 6370997.0
Longitude of projection center: -100 0 0 (100° W)
Latitude of projection center: 45 0 0 (45° N)
False easting (meters): 0.0
False northing (meters): 0.0

Relative to this cooordinate system, the polygon version of the dataset
has the following bounding coordinates (in meters): Xmin = -2031854.125 Xmax = 2516407.500
Ymin = -2116675.500 Ymax = 732416.375

For the 1-km grid version, the bounding coordinates were extended
outwards to match the coverage of the 1-km
landcover and
digital elevation datasets from the USGS EROS Data Center, giving
Xmin = -2050500 Xmax = 2536500
Ymin = -2136500 Ymax = 752500
nrow = 2889 ncol = 4587
cellsize = 1000

For most image processing software packages, the coordinates of the
**center** of the **upper left** (northwest)
cell should be entered as x = -2050000, y = 752000

Last change: 2001 April 6,
R. A. White / raw@essc.psu.edu