23-Class National Land Cover Data Key:

NOTE - All Classes May NOT Be Represented in a specific state data set.
The class number represents the digital value of the class in the data set.
         

NLCD Land Cover Classification System Key - Rev. July 20, 1999
                        
Water                                       
     11 Open Water
     12 Perennial Ice/Snow

Developed
     21 Low Intensity Residential
     22 High Intensity Residential
     23 Commercial/Industrial/Transportation

Barren
     31 Bare Rock/Sand/Clay
     32 Quarries/Strip Mines/Gravel Pits
     33 Transitional    

Forested Upland
     41 Deciduous Forest
     42 Evergreen Forest
     43 Mixed Forest

Shrubland
     51 Shrubland

Non-natural Woody
     61 Orchards/Vineyards/Other

Herbaceous Upland
     71 Grasslands/Herbaceous

Herbaceous Planted/Cultivated
     81 Pasture/Hay
     82 Row Crops
     83 Small Grains
     84 Fallow
     85 Urban/Recreational Grasses

Wetlands
     91 Woody Wetlands
     92 Emergent Herbaceous Wetlands

                        
NLCD Land Cover Classification System Land Cover Class Definitions

Water - All areas of open water or permanent ice/snow cover.

11.  Open Water - All areas of open water; typically 25 percent or greater
cover of water (per pixel).
 
12.  Perennial Ice/Snow - All areas characterized by year-long cover of ice
and/or snow.

Developed - Areas characterized by a high percentage (30 percent or greater)
of constructed materials  (e.g. asphalt, concrete, buildings, etc).
 
21.  Low Intensity Residential - Includes areas with a mixture of constructed
materials and vegetation.  Constructed materials account for 30-80 percent of
the cover. Vegetation may account for 20 to 70 percent of the cover.  These
areas most commonly include single-family housing units.  Population
densities will be lower than in high intensity residential areas.

22.  High Intensity Residential - Includes highly developed areas where
people reside in high numbers.  Examples include apartment complexes and
row houses.  Vegetation accounts for less than 20 percent of the cover.
Constructed materials account for 80 to100 percent of the cover.
 
23. Commercial/Industrial/Transportation  - Includes infrastructure (e.g.
roads, railroads, etc.) and all highly developed areas not classified as High
Intensity Residential.
 
Barren - Areas characterized by bare rock, gravel, sand, silt, clay, or other
earthen material, with little or no "green" vegetation present regardless  of its
inherent ability to support life. Vegetation, if present,  is more widely spaced
and scrubby than that in the "green" vegetated categories; lichen cover may be
extensive.
 
31.  Bare Rock/Sand/Clay - Prennially  barren areas of bedrock, desert
pavement, scarps, talus, slides, volcanic material, glacial debris, beaches, and
other accumulations of earthen material.

32.  Quarries/Strip Mines/Gravel Pits - Areas of  extractive mining activities
with significant surface expression.

33.  Transitional - Areas of sparse vegetative cover (less than 25 percent of
cover) that are dynamically changing from one land cover to another, often
because of land use activities.  Examples include forest clearcuts, a transition
phase between forest and agricultural land, the temporary clearing of
vegetation, and changes due to natural causes (e.g. fire, flood, etc.).

Forested Upland  - Areas characterized by tree cover (natural or semi-natural
woody vegetation, generally greater than 6 meters tall); tree canopy accounts
for 25-100 percent of the cover.

41.  Deciduous Forest - Areas dominated by trees where 75 percent or more
of the tree species shed foliage simultaneously in response to seasonal
change.
 
42.  Evergreen Forest - Areas dominated by trees where 75 percent or more of
the tree species maintain their leaves all year.  Canopy is never without green
foliage.
      
43.  Mixed Forest - Areas dominated by trees where neither deciduous nor
evergreen species represent more than 75 percent of the cover present.

Shrubland - Areas characterized by natural or semi-natural woody vegetation
with aerial stems, generally less than 6 meters  tall,  with individuals or
clumps not touching to interlocking.   Both evergreen and deciduous species
of  true shrubs, young trees, and trees or shrubs  that are small or stunted
because of environmental conditions are included.
 
51.  Shrubland - Areas dominated by shrubs; shrub canopy accounts for
25-100 percent of the cover.  Shrub cover is generally  greater than 25 percent
when tree cover is less than 25 percent.  Shrub cover may be less than 25
percent in cases when the cover of other life forms (e.g. herbaceous or tree) is
less than 25 percent and shrubs cover exceeds the cover of the other life
forms.

Non-natural Woody - Areas dominated by non-natural woody vegetation;
non-natural woody vegetative canopy accounts for 25-100 percent of the
cover.   The non-natural woody classification is subject to the availability of
sufficient ancillary data to differentiate non-natural woody vegetation from
natural woody vegetation.

61.  Orchards/Vineyards/Other - Orchards, vineyards, and other areas planted
or maintained for the production of fruits, nuts, berries, or ornamentals.

Herbaceous Upland - Upland areas characterized by natural or semi-natural
herbaceous vegetation; herbaceous vegetation accounts for 75-100 percent of
the cover.
 
71.  Grasslands/Herbaceous - Areas dominated  by upland grasses and forbs.
In rare cases, herbaceous cover is less than 25 percent, but exceeds the
combined cover of the woody species present.  These areas are not subject to
intensive management, but they are often utilized for  grazing.

Planted/Cultivated - Areas characterized by herbaceous vegetation that
has been planted or is intensively managed for the production of food, feed,
or fiber; or is maintained in developed settings for specific purposes.
Herbaceous vegetation accounts for 75-100 percent of the cover. 
        
81.  Pasture/Hay - Areas of grasses, legumes, or grass-legume  mixtures
planted for livestock grazing or the production of seed or hay crops.
      
82. Row Crops - Areas used for the production of crops, such as corn,
soybeans, vegetables, tobacco, and cotton.
     
83.  Small Grains - Areas used for the production of graminoid crops such as
wheat, barley, oats, and rice.
       
84.  Fallow - Areas used for the production of crops that are temporarily
barren or with sparse  vegetative cover as a result of  being tilled in a
management practice that incorporates prescribed alternation between
cropping and tillage.

85.  Urban/Recreational Grasses - Vegetation (primarily grasses) planted in
developed settings for recreation, erosion control, or aesthetic purposes.
Examples include parks, lawns, golf courses, airport grasses, and industrial
site grasses.
   
Wetlands - Areas where the soil or substrate is periodically saturated with or
covered with water as defined by Cowardin et al.     

91.  Woody Wetlands - Areas where forest or shrubland vegetation accounts
for 25-100 percent of the cover and  the soil or substrate is periodically
saturated with or covered with water.       

92.  Emergent Herbaceous Wetlands - Areas where  perennial herbaceous
vegetation accounts for 75-100 percent of the cover and the soil or substrate
is periodically saturated with or covered with water.