USGS EROS Archive - Land Cover Products - Global Forest Resources Assessment (FRA 2000) Overview

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Overview

Sources/Usage: Public Domain. View Media Details

Since 1947, the Food and Agricultural Organization (FAO) of the United Nations (UN), at the request of its member nations and the world community, has regularly reported on the state, changes and conditions of the world's forests about every 10 years. The present survey, known as the Global Forest Resources Assessment (FRA 2000), provides crucial information describing the state and conditions of forest resources for the year 2000, and their changes over the last 20 years. FRA 2000 also includes new parameters on ecological aspects of forests, protected forests, non-wood goods and services, and a set of global maps.

FRA 2000 is coordinated by FAO and carried out in cooperation with the United Nations Economic Commission for Europe (UNECE), the United Nations Environment Programme (UNEP), UN member countries and external partners, including the U.S. Geological Survey (USGS) National Center for Earth Resources Observation and Science (EROS) in the USA, the Tropical Agricultural Research and Higher Education Center in Costa Rica and the World Conservation Monitoring Centre in the United Kingdom. Funding from the Governments of Finland, Sweden, Switzerland, and the United Kingdom were instrumental in supporting the development of the global forest map, as were in-kind contributions from the USGS and the U.S. Forest Service. Countries and regional cooperators were involved in the mapping exercise.

Sources/Usage: Public Domain. View Media Details

The global forest map is one of the many outputs produced by FRA 2000. The assessment includes several volumes of text and statistical information found on the FAO website and in a series of printed volumes, available in 2001 at authorized locations around the world.

The forest map was produced from the Global Land Cover Characteristics (GLCC) Database, a land cover dataset at one-kilometer resolution derived from Advanced Very High Resolution Radiometer (AVHRR) satellite images. Both the global forest cover and global forest density maps are in the Interrupted Goode Homolosine map projection. The land cover classes shown on the forest map were derived by aggregating GLCC classes with additional criteria derived from other datasets.

Sources/Usage: Public Domain. View Media Details

Methodology

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 fo the forest and nonforest classification.

Data Specifications For Global Forest Cover and Global Forest Canopy Density

• Image Type:               Generic Flat Binary, Byte Interleave By Line (BIL)
• Files Size:                   537,404 Kbytes
• Data Type:                  Byte (8 Bit, 0-255)
• Number of Lines:        15,059
• Number of Samples:   36,543
• Pixel Size:                   1,000 Meters
• Scale:                          Global
• Projection:                  Interrupted Goode Homolosine
• Projection Unit:           Meters
• Spheroid:                    Sphere of radius at 6,370,997 meters
• Datum:                        Sphere of radius at 6,370,997 meters
• Upper Left Xcoord:      -17359000
• Upper Left Ycoord:      8673000
• Legend: 
  • Global Forest Cover: 1=Closed Forest, 2=Open or Fragmented Forest, 3=Other Wooded Land,
  • 4=Other Land Cover, 5=Water
  • Global Forest Canopy Density: Forest Canopy Density Ranging from 1 - 100 Percent

Additional Information

• Global Land Cover Characterization (GLCC) 

Data Access

EarthExplorer can be used to search, preview, and download GLCC data. The collections are located under the Land Cover Products data set.