The objective of this study was to create a land cover map derived from 1 kilometer AVHRR data using all available bands, derived Normalized Difference Vegetation Index (NDVI), and a full year of data (April 1992-March 1993). This thematic map was resampled to 0.25, 0.5 and 1.0 degree grids for ISLSCP II. During this re-processing, the original University of Maryland (UMD) land cover type and fraction maps were adjusted to match the water/land fraction of the ISLSCP II land/water mask. These maps were generated for use by modelers of global biogeochemical cycles and others in need of an internally consistent, global depiction of land cover. The AVHRR 1km map was also one of the MODIS (Moderate Resolution Imaging Spectroradiometer) at-launch land cover maps.
The data set describes the geographic distributions of 13 classes of vegetation cover (plus water and unclassified classes) based on a modified International Geosphere-Biosphere Programme (IGBP) legend. The data set also provides the fraction of each of the 15 classes within the coarser resolution cells. This data set provides global classified land cover grids at three spatial resolutions of 0.25, 0.5 and 1.0 degree in latitude and longitude.
This data set is one of the products of the International Satellite Land-Surface Climatology Project, Initiative II (ISLSCP II) data collection, which contains 50 global time series data sets for the ten-year period 1986 to 1995. A complete description of the data, their derivation, acknowledgements, and references provided by the ISLSCP II Data Management Staff is included with this data set as a companion file named 1_umd_landcover_doc.pdf
ISLSCP II is a consistent collection of data sets that were compiled from existing data sources and algorithms, and were designed to satisfy the needs of modelers and investigators of the global carbon, water and energy cycle. The data were acquired from a number of U.S. and international agencies, universities, and institutions. The data and documentation have undergone two peer reviews.
ISLSCP is one of several projects of Global Energy and Water Cycle Experiment (GEWEX) [http://www.gewex.org/] and has the lead role in addressing land-atmosphere interactions -- process modeling, data retrieval algorithms, field experiment design and execution, and the development of global data sets.
Cite this data set as follows:
DeFries, R.S. and M. Hansen. 2010. ISLSCP II University of Maryland Global Land Cover Classifications, 1992-1993. In Hall, Forrest G., G. Collatz, B. Meeson, S. Los, E. Brown de Colstoun, and D. Landis (eds.). ISLSCP Initiative II Collection. Data set. Available on-line [http://daac.ornl.gov/] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/969
The archived data sets for ISLSCP II have been organized by categories. This data set is in the vegetation category--a collection of vegetation and albedo data sets.
Data Set Spatial Extent: Global gridded
Westernmost Longitude: -180 W
Easternmost Longitude: 180 E
Northernmost Latitude: 90 N
Southernmost Latitude: -90 S
Data Set Spatial Resolution: one, half, and quarter degree in both latitude and longitude
Data Set Temporal Extent: April 1992 through March 1993
Data File Format
All of the data files in each data set within the ISLSCP Initiative II data collection are in ESRI ASCII GRID format for ArcInfo. The file format consists of numerical fields of varying length, which are delimited by a single space and arranged in columns and rows.
The data files have been combined according to spatial resolution: one degree, half degree, and quarter degree respectively.
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.
For each spatial resolution there is a data file for each 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. See table below.
Land Cover Type Codes and Definitions
|1||Evergreen Needleleaf Forest|
|2||Evergreen Broadleaf Forest|
|3||Deciduous Needleleaf Forest|
|4||Deciduous Broadleaf Forest|
|8||Closed Bushlands or Shrublands|
|13||Urban and Built-up|
Data file naming conventions are described in the 0_umd_landcover_readme.txt
These data are available through the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC) [http://daac.ornl.gov].
Telephone: +1 (865) 241-3952