This data set is an expanded version of the Costa et al. (2000) data set and consists of a single grid with values of 1 for cells within the basins and 0 for cells outside. The resolution of the data set is 5 x 5 min (approximately 9 x 9 km). The original data set covered the area from 6° N to 21° S and from 44° W to 80° W. The area of this data set, however, was slightly increased to be consistent with definition of the study area of the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) in South America (i.e., 10° N to 25° S, 30° to 85° W). The data file is in ASCII GRID format.
The methodology described in the documentation of the original data set is as follows. Initially, two borders were drawn independently. The first one was digitized from a 1:5.000.000 hydrogeological map of South America that has the borders of the Amazon and Tocantins basins marked. The second one was digitized from a 1:000.000 map of Northern South America. This map does not show the basin borders, so it was assumed that the border would be in the middle point between nearby rivers that run into and out of the basin. Then the two maps were overlaid. The final version was obtained together with the river directions data set, to match the drainage areas of fluviometric stations, provided by ANEEL, the Brazilian Agency for Waters and Electrical Energy.
More information can be found at ftp://daac.ornl.gov/data/lba/surf_hydro_and_water_chem/basin_border/comp/basin_readme.pdf.
Cite this data set as follows:
Costa, M. H., C. H. C. Oliveira, R. G. Andrade, T. R. Bustamante, F. A. Silva, and M. T. Coe. 2003. LBA Regional Boundary for the Amazon and Tocantins River Basins, 5-min. Data set. Available on-line [http://www.daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/670.
Costa, M. H., C. H. C. Oliveira, R. G. Andrade, T. R. Bustamante, F. A. Silva, and M. T. Coe. 2000. Amazon and Tocantins Basins Border. Data set. Federal University of Vicosa, Vicosa, MG, Brazil.
Instituto Brasileiro de Geografia e Estatística (Brasilian Institute of National Statistics and Geography). 1972. International chart of the world on the millionth scale. Brazil.
UNESCO, DNPM, and CPRM. 1996. Mapa hidrogeologico de America del Sur. Braisilia, Brazil.
The data file is in ASCII GRID format for ArcInfo. Complete format information can be found at ftp://daac.ornl.gov/data/lba/surf_hydro_and_water_chem/basin_border/comp/basin_readme.pdf.