1:250,000 Scale Quadrangles of Land Use/Land Cover GIRAS Spatial Data in the Conterminous U.S.

This is land use/land cover digital data collected by USGS and converted to ARC/INFO by the EPA. This data is useful for environmental assessment of land use patterns with respect to water quality analysis, growth management, and other types of environmental impact assessment. Use may be limited due to currency. Land use and land cover data LU/LC collected by the USGS NMD is useful for environmental assessment of land use patterns with respect to water quality analysis, growth management, and other types of environmental impact assessment. Data are meant to be used by quadrangle, or among adjacent quadrangles where temporally contiguous. Can be used in any geographic application where intermediate scale land use data are appropriate and the dates are representative. Each quadrangle of land use data has a different representative date. Date ranges from mid 1970s to early 1980s are common. When joined together these quadrangles will not likely match along edges due to differences in interpretation and time coverage. Edges of each map file were manually digitized and may not join neighboring maps. If GIRASNEAT program has been applied (see LOG at end) then edges have been mathematically recalculated to join without overlap or gaps in coverage with adjacent maps. The GIRAS series can include several themes of spatial data. The most common, described here, is the land use and land cover data. Land use was mapped and coded using the Anderson classification system (Anderson others,1976) which is a hierarchical system of general (level 1) to more specific (level 2) characterization. Some agencies have taken this to a level 3 classification -- but this has not been done in the GIRAS series. The salient attribute managed for this polygon data set in the polygon attribute table (PAT) is the column named LUCODE containing the Anderson level 2 classification. The first digit represents the level one value and the second digit (ones place) represents the subdivision of the level 1 or level 2 value. The Anderson land use codes are: 1 Urban or built-up land 11 Residential 12 Commercial and services 13 Industrial 14 Transportation, communication, utilities 15 Industrial and commercial complexes 16 Mixed urban or built-up land 17 Other urban or built-up land 2 Agricultural land 21 Cropland and pasture 22 Orchards, groves, vineyards, nurseries, and ornamental horticultural 23 Confined feeeding operations 24 Other agricultural land 3 Rangeland 31 Herbaceous rangeland 32 Shrub and brush rangeland 33 Mixed rangeland 4 Forest land 41 Deciduous forest land 42 Evergreen forest land 43 Mixed forest land 5 Water 51 Streams and canals 52 Lakes 53 Reservoirs 54 Bays and estuaries 6 Wetland 61 Forested wetland 62 Nonforested wetland 7 Barren land 71 Dry salt flats 72 Beaches 73 Sandy areas not beaches 74 Bare exposed rock 75 Strip mines, quarries, gravel pits 76 Transitional areas 8 Tundra 81 Shrub and brush tundra 82 Herbaceous tundra 83 Bare ground 84 Wet tundra 85 Mixed tundra 9 Perennial snow or ice 91 Perennial snowfields 92 Glaciers