557 Earth sciences of North America

U.S. National Vegetation Classification

"Classifying vegetation is a critical to sound ecological science and efficient land assessment, management and planning. The National Vegetation Classification (NVC) is a central organizing framework for how all vegetation in the United States is inventoried and studied, from broad scale formations (biomes) to fine-scale plant communities. The purpose of the NVC is to produce uniform statistics about vegetation resources across the nation, based on vegetation data gathered at local, regional, or national levels.

National Land Cover Data Classification Schemes

"NLCD 1992 was a success, and its success had a lot to do with building the momentum for NLCD 2001. NLCD 2001 improves upon NLCD 1992 in three important ways. Whereas NLCD 1992 was simply a land-cover data set, NLCD 2001 is a land-cover database comprised of three elements: land cover, impervious surface and canopy density. Second, NLCD 2001 used improved classification algorithms, which have resulted in data with more precise rendering of spatial boundaries between the 16 classes (an additional nine classes are available in coastal areas and another four classes in Alaska only).

"NLCD 1992 was a success, and its success had a lot to do with building the momentum for NLCD 2001. NLCD 2001 improves upon NLCD 1992 in three important ways. Whereas NLCD 1992 was simply a land-cover data set, NLCD 2001 is a land-cover database comprised of three elements: land cover, impervious surface and canopy density. Second, NLCD 2001 used improved classification algorithms, which have resulted in data with more precise rendering of spatial boundaries between the 16 classes (an additional nine classes are available in coastal areas and another four classes in Alaska only).