forrest@0: forrest@0: ############################################################################## forrest@0: # University of Maryland Global Land Cover Classifications # forrest@0: # at 0.25, 0.5 and 1 degree (1992-1993) # forrest@0: ############################################################################## forrest@0: forrest@0: The files in this directory were provided by Drs. Ruth DeFries and Matt Hansen forrest@0: from the Department of Geography at the University of Maryland, College Park. forrest@0: These are global, coarse resolution (1/4, 1/2 and 1 degree spatial resolutions) forrest@0: land cover classifications (dominant type and fractional cover) generated using forrest@0: data from the Advanced Very High Resolution Radiometer (AVHRR) (see Hansen et forrest@0: al. 2000). forrest@0: forrest@0: The objective of this study was to create a land cover map derived from 1 forrest@0: kilometer AVHRR data using all available bands and derived Normalized Difference forrest@0: Vegetation Index (NDVI) and a full year of data (April 1992-March 1993). This forrest@0: thematic map was resampled to 0.25, 0.5 and 1.0 degree grids for the forrest@0: International Satellite Land Surface Climatology Project (ISLSCP) data forrest@0: initiative II. During this re-processing, the original UMD land cover type and forrest@0: fraction maps were adjusted to match the water/land fraction of the ISLSCP II forrest@0: land/water mask. These maps were generated for use by modelers of global forrest@0: biogeochemical cycles and others in need of an internally consistent, forrest@0: global depiction of land cover. This 1km map was also one of the MODIS (Moderate forrest@0: Resolution Imaging Spectroradiometer) at-launch land cover maps. forrest@0: forrest@0: The data set describes the geographic distributions of 13 classes of vegetation forrest@0: cover (plus water and unclassified classes) based on a modified International forrest@0: Geosphere-Biosphere Programme (IGBP) legend (Rasool 1992). The data set also forrest@0: provides the fraction of each of the 15 classes within the coarser resolution forrest@0: cells. The data set is provided at three spatial resolutions of 0.25, 0.5 and 1 forrest@0: degrees in latitude and longitude. We refer the reader to the reference below forrest@0: for more information on data processing of the original 1km data set. forrest@0: forrest@0: Please acknowledge Drs. DeFries and Hansen and the ISLSCP2 data collection when forrest@0: these data are used. Please cite the following publications when these data are forrest@0: used: forrest@0: forrest@0: Hansen, M. C., DeFries, R.S., Townshend, J.R.G., and Sohlberg, R., 2000, Global forrest@0: land cover classification at 1km spatial resolution using a classification tree forrest@0: approach, International Journal of Remote Sensing, 21, 1331-1364. forrest@0: forrest@0: Any problems encountered with the data set should be reported to Eric Brown de forrest@0: Colstoun at ericbdc@ltpmail.gsfc.nasa.gov forrest@0: forrest@0: ############################################################################## forrest@0: forrest@0: File Name Convention forrest@0: -------------------- forrest@0: The data sets in this directory are provided at three spatial resolutions of forrest@0: 0.25, 0.5 and 1 degrees lat./long. For each spatial resolution there is a land forrest@0: cover type classification layer (with numbers from 0 to 14) and 15 associated forrest@0: layers that provide the fraction, from 0 to 100, of each land cover type per forrest@0: cell. The land cover type files are named umd_landcover_class_XX.asc, where XX forrest@0: is qd, hd, or 1d, denoting a spatial resolution of 1/4, 1/2 or 1 degrees, forrest@0: respectively. The fractional files are called umd_landcover_XX_cZZ.asc, where XX forrest@0: is the same as above, and ZZ is a number from 00 to 14 which represents the land forrest@0: cover type code as described below. As an example, the file named forrest@0: umd_landcover_qd_c02.asc is the fraction of Evergreen Broadleaf Forest at a forrest@0: quarter degree spatial resolution. This file is associated with the forrest@0: umd_landcover_class_qd.asc land cover type file. forrest@0: forrest@0: ############################################################################## forrest@0: forrest@0: ASCII File Format forrest@0: ------------------ forrest@0: All of the files in the ISLSCP Initiative II data collection are in the ASCII, forrest@0: or text format. The file format consists of numerical fields of varying length, forrest@0: which are delimited by a single space and arranged in columns and rows. The forrest@0: values in the land cover class type files are written as integers from 0 to 14. forrest@0: All values in the land cover fraction files are written as real numbers. forrest@0: forrest@0: The files at different spatial resolutions each contain the following numbers of forrest@0: columns and rows: forrest@0: One degree: 360 columns by 180 rows forrest@0: 1/2 degree: 720 columns by 360 rows forrest@0: 1/4 degree: 1440 columns by 720 rows forrest@0: forrest@0: All files are gridded to a common equal-angle lat/long grid, where the forrest@0: coordinates of the upper left corner of the files are located at 180oW, 90oN and forrest@0: the lower right corner coordinates are located at 180oE, 90oS. Data in the files forrest@0: are ordered from North to South and from West to East beginning at 180 degrees forrest@0: West and 90 degrees North. forrest@0: forrest@0: The data files are PKZip compressed. On UNIX, they can be decompressed using the forrest@0: "unzip -a" command. On Windows, they can be decompressed using WinZip or other forrest@0: PKZip software. On the Macintosh, they can be decompressed using Stuffit forrest@0: Expander. forrest@0: forrest@0: ################################################################################ forrest@0: forrest@0: Land Cover Type Codes and Definitions forrest@0: ------------------------------------- forrest@0: The following 15 classes are used. Note that here are no cells with a value of forrest@0: 13 (Urban and Builtup) in the 1degree land cover type file. forrest@0: forrest@0: 0 = Water bodies: oceans, seas, lakes, reservoirs, and rivers. Can be either forrest@0: fresh or salt water. This class is derived from a land/water mask. forrest@0: forrest@0: 1 = Evergreen Needleleaf Forests: lands dominated by trees with a percent canopy forrest@0: cover >60% and height exceeding 5m. Almost all trees remain green all year. forrest@0: Canopy is never without green foliage. forrest@0: forrest@0: 2 = Evergreen Broadleaf Forests: lands dominated by trees with a percent canopy forrest@0: cover > 60% and height exceeding 5m. Almost all trees remain green all year. forrest@0: Canopy is never without green foliage. forrest@0: forrest@0: 3 = Deciduous Needleleaf Forest: lands dominated by trees with a percent canopy forrest@0: cover >60% and height exceeding 5m. Trees shed their leaves simultaneously in forrest@0: response to cold seasons. forrest@0: forrest@0: 4 = Deciduous Broadleaf Forests: lands dominated by trees with a percent canopy forrest@0: cover >60% and height exceeding 5m. Trees shed their leaves simultaneously in forrest@0: response to dry or cold seasons. forrest@0: forrest@0: 5 = Mixed Forests: lands dominated by trees with a percent canopy cover >60% and forrest@0: height exceeding 5m. Consists of tree communities with interspersed mixtures or forrest@0: mosaics of needleleaf and deciduous forest types. Neither type has <25% or >75% forrest@0: landscape coverage. forrest@0: forrest@0: 6 = Woodlands: lands with herbaceous or woody understories and tree canopy cover forrest@0: of >40% and <60%. Trees exceed 5m in height and can be either evergreen or forrest@0: deciduous. forrest@0: forrest@0: 7 = Wooded Grasslands/Shrublands: lands with herbaceous or woody understories and forrest@0: tree canopy cover of >10% and <40%. Trees exceed 5m in height and can be either forrest@0: evergreen or deciduous. forrest@0: forrest@0: 8 = Closed Bushlands or Shrublands: lands dominated by bushes or shrubs. Bush and forrest@0: shrub percent canopy cover is >40%. Bushes do not exceed 5m in height. Shrubs forrest@0: or bushes can be either evergreen or deciduous. Tree canopy cover is <10%. The forrest@0: remaining cover is either barren or herbaceous. forrest@0: forrest@0: 9 = Open Shrubland: lands dominated by shrubs. Shrub canopy cover is >10% and forrest@0: <40%. Shrubs do not exceed 2m in height and can be either evergreen or forrest@0: deciduous. The remaining cover is either barren or of annual herbaceous type. forrest@0: forrest@0: 10 = Grasslands: lands with continuous herbaceous cover and <10% tree or shrub forrest@0: canopy cover. forrest@0: forrest@0: 11 = Croplands: lands with >80% of the landscape covered in crop-producing fields. forrest@0: Note that perennial woody crops will be classified as the appropriate forest or forrest@0: shrubs land cover type. forrest@0: forrest@0: 12 = Barren: lands of exposed soil, sand, rocks, snow or ice which never have more forrest@0: than 10% vegetated cover during any time of year. forrest@0: forrest@0: 13 = Urban and Builtup: land covered by buildings and other man-made structures. forrest@0: Note that this class is not mapped from the AVHRR imagery but is developed from forrest@0: the populated places layer that is part of the Digital Chart of the World (Danko forrest@0: 1992). forrest@0: forrest@0: 14 = Unclassified: Points where the ISLSCP2 land/sea mask was labeled as land and forrest@0: the UMD original data had sea and which could not be filled in from a 3 by 3 forrest@0: average of surrounding cells. forrest@0: