The lba_basin.dat.gz file contains the Amazon and Tocantins River Basins Border. The file contains a single 5 x 5 min (approx. 9 x 9 km) grid. Cells within the basins have a value of 1 cells outside the basin have a value of 0. The original data set covered the area of 6N to 21S and 80W to 44W. This area was slightly expanded in the version of the data set available for download from Oak Ridge National Laboratory to be consistent with the LBA study area as defined for the ORNL/LBA subsetting activity. This README file contains information regarding: 1. Data format 2. Procedure used to create the LBA study area subset 3. Legend and data source ------------------------------------------------------------------- DATA FORMAT ------------------------------------------------------------------- The downloadable file, lba_basin.dat.gz, is a UNIX compressed ASCII file. The data file, lba_basin.dat, is in ASCII Grid format for ArcInfo. The file contains a single ASCII array with integer Coordinates listed below are in decimal degrees. Rows 420 Columns 660 UpLeftX -85 UpLeftY 10 LoRightX -30 LoRightY -25 cellsize 0.083333 Projection geographic The ASCII file consists of header information containing a set of keywords, followed by cell values in row-major order. The file format is {NODATA_VALUE xxx} row 1 row 2 . . . row n where xxx is a number, and the keyword NODATA_VALUE is optional and defaults to -9999. Row 1 of the data is at the top of the grid, row 2 is just under row 1 and so on. The end of each row of data from the grid is terminated with a carriage return in the file. To import this file into ArcInfo use the following command at an ARC prompt: ASCIIGRID {INT | FLOAT} Arguments - the ASCII file to be converted. - the name of the grid to be created. {INT | FLOAT} - the data type of the output grid. INT - an integer grid will be created. FLOAT - a floating-point grid will be created. ------------------------------------------------------------------- PROCEDURE USED TO CREATE THE LBA STUDY AREA SUBSET ------------------------------------------------------------------- The original data file was provided by Marcos Heil Costa, at Federal University of Vicosa (UFV), Vicosa, MG, Brazil (mhcosta@mail.ufv.br). The original data were imported into ArcInfo using the ASCIIGRID command. The original data set covered the area of 6N to 21S and 80W to 44W. In order to be consistent with the other data sets provided for the LBA study area, the data set needed to be expanded to 10N to 25S and 85W to 30W. The extra cells added to the original data were all given the value of 0. An ASCII array was created from the new expanded grid using the GRID command GRIDASCII. file.dat = GRIDASCII(expanded_grid) ------------------------------------------------------------------- LEGEND & ADDITIONAL SOURCES OF INFORMATION ------------------------------------------------------------------- 0 outside basin 1 within basin For additional information please contact Marcos Heil Costa, at Federal University of Vicosa (UFV), Vicosa, MG, Brazil (mhcosta@mail.ufv.br) ------------------------------------------------------------------- DATA SET CITATION ------------------------------------------------------------------- Costa, Marcos Heil, Carlos Henrique C. Oliveira, Ricardo G. Andrade, Thiago R. Bustamante, Fabricio A. Silva and Michael T. Coe. 2000. Amazon and Tocantins basins border. Federal University of Vicosa (UFV), Vicosa, MG, Brazil. Data available on-line at: ftp://www-eosdis.ornl.gov/data/lba regional/basin_border