Your browser does not support scripts.
USGS - science for a changing world

Global Land Cover Characterization

The USGS/NASA Version 0 data sets have migrated to a new domain within the USGS Long Term Archive (LTA).
Please update your Global Land Cover Characterization link to

You will be re-directed to this page in 20 seconds.


Global Forest Resources Assessment (FRA 2000)

Global Forest Home Overview Methodology Data Specifications Header File Download Data


Boreal Forest

The forest cover map, produced at the U.S. Geological Survey (USGS) National Center for Earth Resources Observation and Science (EROS), has five classes: closed forest, open or fragmented forest, other wooded land, other land cover, and water. The classes were delineated based on circa 1995 monthly AVHRR composite images processed using a hybrid maximum-NDVI and minimum-red compositing technique. Modified mixture analysis, geographic stratification, and other classification techniques were used to estimate forest canopy density within 1 square kilometer pixels, which formed the basis for the first two classes: the closed forest (40% - 100% canopy cover), and open or fragmented forest (10 - 40% canopy cover). The remaining three FAO classes were derived using the USGS global land cover characteristics database as a stratification tool. Validated on the basis of existing reference data sets, the map is estimated to be 77 percent accurate for the first four classes (no reference data were available for water), and 86 percent accurate for the forest and nonforest classification.

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information:
Page Last Modified: June 23, 2008