This data set contains global land cover in terms of 15 major vegetation types, plus water, in the absence of alteration by humans. It forms a complement to the historical croplands data set developed by Ramankutty and Foley (2010). By overlaying the two, one can determine the extent to which natural vegetation has been cleared for cultivation. This data set can be used directly within spatially-explicit climate and biogeochemical models. There are four total files in this data set. Two files contain the land cover types representing potential natural vegetation in the absence of human alteration, and two other files contain those points in the original data set (Ramankutty and Foley 1999) that have been modified in order to match the land/water mask of the ISLSCP Initiative II.
The geographic distribution of contemporary land cover types can be derived from remotely-sensed data. However, humans now dominate much of the world and there is little evidence of the pre-human-settlement natural vegetation or Potential Natural Vegetation (PNV). PNV, as defined here, does not necessarily represent the world’s natural pre-human-disturbance vegetation. Rather, our definition of PNV represents the world’s vegetation cover that would most likely exist for 1986-1995 in equilibrium with present-day climate and natural disturbance, in the absence of human activities.
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_potential_veg_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:
Ramankutty, N. and J.A. Foley. 2010. ISLSCP II Potential Natural Vegetation Cover. In Hall, Forest 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/961
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: half and one degree in both latitude and longitude
Data Set Temporal Extent: January 1, 1986 through December 31, 1995
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 files at different spatial resolutions each contain the following numbers of columns and rows:
One degree (1d): 360 columns by 180 rows
Half degree (hd): 720 columns by 360 rows
Data File Names:
The files contain the land cover
types representing potential natural vegetation before human alteration. The two"diffs" files contain those points in the original
data set (Ramankutty and Foley 1999) that have been
modified in order to match the land/water mask of the ISLSCP Initiative
Data file naming conventions are described in the 0_potential_veg_readme.txt
Potential land cover type codes:
Data values are written as integers varying from 0 to 16 for the .asc files and 0 to 15 for the "diffs_XX.asc" files.
Each number in the file represents a Vegetation Class for that cell. These Class Numbers are listed below.
|Class #||Biome Type|
|0||Water bodies (Water bodies or missing data for "diffs" files)|
|1||Tropical Evergreen Forest/Woodland|
|2||Tropical Deciduous Forest/Woodland|
|3||Temperate Broadleaf Evergreen Forest/Woodland|
|4||Temperate Needleleaf Evergreen Forest/Woodland|
|5||Temperate Deciduous Forest/Woodland|
|6||Boreal Evergreen Forest/Woodland|
|7||Boreal Deciduous Forest/Woodland|
|16||No data over land (not included in the "diffs" files)|
Ramankutty, N., and J.A. Foley, Estimating historical changes in global land cover: Croplands from 1700 to 1992, Global Biogeochemical Cycles, 13, 997-1027, 1999. doi:10.1029/1999GB900046
Ramankutty, N. and J.A. Foley. 2010. ISLSCP II Historical Croplands Cover, 1700-1992. In Hall, Forest 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/966
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