File Name Convention -------------------- The data sets in this directory are provided at three spatial resolutions of 0.25, 0.5 and 1 degrees lat./long. For each spatial resolution there is a land cover type classification layer (with numbers from 0 to 14) and 15 associated layers that provide the fraction, from 0 to 100, of each land cover type per cell. The land cover type files are named umd_landcover_class_XX.asc, where XX is qd, hd, or 1d, denoting a spatial resolution of 1/4, 1/2 or 1 degrees, respectively. The fractional files are called umd_landcover_XX_cZZ.asc, where XX is the same as above, and ZZ is a number from 00 to 14 which represents the land cover type code as described below. As an example, the file named umd_landcover_qd_c02.asc is the fraction of Evergreen Broadleaf Forest at a quarter degree spatial resolution. This file is associated with the umd_landcover_class_qd.asc land cover type file. ############################################################################## ASCII File Format ------------------ All of the files in the ISLSCP Initiative II data collection are in the ASCII, or text format. The file format consists of numerical fields of varying length, which are delimited by a single space and arranged in columns and rows. The values in the land cover class type files are written as integers from 0 to 14. All values in the land cover fraction files are written as real numbers. The files at different spatial resolutions each contain the following numbers of columns and rows: One degree: 360 columns by 180 rows 1/2 degree: 720 columns by 360 rows 1/4 degree: 1440 columns by 720 rows All files are gridded to a common equal-angle lat/long grid, where the coordinates of the upper left corner of the files are located at 180oW, 90oN and the lower right corner coordinates are located at 180oE, 90oS. Data in the files are ordered from North to South and from West to East beginning at 180 degrees West and 90 degrees North. ################################################################################ Land Cover Type Codes and Definitions ------------------------------------- The following 15 classes are used. Note that here are no cells with a value of 13 (Urban and Builtup) in the 1degree land cover type file. 0 = Water bodies: oceans, seas, lakes, reservoirs, and rivers. Can be either fresh or salt water. This class is derived from a land/water mask. 1 = Evergreen Needleleaf Forests: lands dominated by trees with a percent canopy cover >60% and height exceeding 5m. Almost all trees remain green all year. Canopy is never without green foliage. 2 = Evergreen Broadleaf Forests: lands dominated by trees with a percent canopy cover > 60% and height exceeding 5m. Almost all trees remain green all year. Canopy is never without green foliage. 3 = Deciduous Needleleaf Forest: lands dominated by trees with a percent canopy cover >60% and height exceeding 5m. Trees shed their leaves simultaneously in response to cold seasons. 4 = Deciduous Broadleaf Forests: lands dominated by trees with a percent canopy cover >60% and height exceeding 5m. Trees shed their leaves simultaneously in response to dry or cold seasons. 5 = Mixed Forests: lands dominated by trees with a percent canopy cover >60% and height exceeding 5m. Consists of tree communities with interspersed mixtures or mosaics of needleleaf and deciduous forest types. Neither type has <25% or >75% landscape coverage. 6 = Woodlands: lands with herbaceous or woody understories and tree canopy cover of >40% and <60%. Trees exceed 5m in height and can be either evergreen or deciduous. 7 = Wooded Grasslands/Shrublands: lands with herbaceous or woody understories and tree canopy cover of >10% and <40%. Trees exceed 5m in height and can be either evergreen or deciduous. 8 = Closed Bushlands or Shrublands: lands dominated by bushes or shrubs. Bush and shrub percent canopy cover is >40%. Bushes do not exceed 5m in height. Shrubs or bushes can be either evergreen or deciduous. Tree canopy cover is <10%. The remaining cover is either barren or herbaceous. 9 = Open Shrubland: lands dominated by shrubs. Shrub canopy cover is >10% and <40%. Shrubs do not exceed 2m in height and can be either evergreen or deciduous. The remaining cover is either barren or of annual herbaceous type. 10 = Grasslands: lands with continuous herbaceous cover and <10% tree or shrub canopy cover. 11 = Croplands: lands with >80% of the landscape covered in crop-producing fields. Note that perennial woody crops will be classified as the appropriate forest or shrubs land cover type. 12 = Barren: lands of exposed soil, sand, rocks, snow or ice which never have more than 10% vegetated cover during any time of year. 13 = Urban and Builtup: land covered by buildings and other man-made structures. Note that this class is not mapped from the AVHRR imagery but is developed from the populated places layer that is part of the Digital Chart of the World (Danko 1992). 14 = Unclassified: Points where the ISLSCP II land/sea mask was labeled as land and the UMD original data had sea and which could not be filled in from a 3 by 3 average of surrounding cells.