The wetlands.tar.gz file contains a subset of The Global Distribution of Freshwater Wetlands database. The subset is for the LBA-Ecology study area. This README file contains information regarding: 1. Data format 2. Procedure used to create the Amazon subset 3. Legend and data source ------------------------------------------------------------------- DATA FORMAT ------------------------------------------------------------------- The downloadable file, wetlands.tar.gz, is a UNIX compressed tar file. Once the file is untarred there are 51 separate files (listed below in alphabetical order). The first part of each filename indicates the wetland category. Filenames containing the string Œ-ackš contain merged data from both Aselman & Crutzen and Klinger data sets. Otherwise the files bogs.1x1 and fens.1x1 contain only the Aselman & Crutzen data. For more information please refer to the original documentation ( URL given in the ŒLegend and data sourceš section of the README file). All data values represent percentage area covered by the wetland category. 1. apr-ricepd.1x1 --> April rice paddies 2. aug-ricepd.1x1 --> August rice paddies 3. bogs.1x1* --> Bog (Aselman & Crutzen data only) 4. bogs_ack.1x1* --> Bog (merged Aselman & Crutzen and Klinger data) 5. dec-ricepd.1x1 --> December rice paddies 6. feb-ricepd.1x1 --> February rice paddies 7. fens.1x1* --> Fen (Aselman & Crutzen data only) 8. fens_ack.1x1* --> Fen (merged Aselman & Crutzen and Klinger data) 9. fld.1x1 --> all floodplains, discounting seasonality 10. fldapr.1x1 --> April seasonal floodplain 11. fldaug.1x1 --> August seasonal floodplain 12. flddec.1x1 --> December seasonal floodplain 13. fldfeb.1x1 --> February seasonal floodplain 14. fldjan.1x1 --> January seasonal floodplain 15. fldjul.1x1 --> July seasonal floodplain 16. fldjun.1x1 --> June seasonal floodplain 17. fldmar.1x1 --> March seasonal floodplain 18. fldmay.1x1 --> May seasonal floodplain 19. fldnov.1x1 --> November seasonal floodplain 20. fldoct.1x1 --> October seasonal floodplain 21. fldsep.1x1 --> September seasonal floodplain 22. flmiss.1x1 --> floodplains, seasonality could not be determined 23. jan-ricepd.1x1 --> January rice paddies 24. jul-ricepd.1x1 --> July rice paddies 25. jun-ricepd.1x1 --> June rice paddies 26. lakes.1x1 --> Lakes 27. mar-ricepd.1x1 --> March rice paddies 28. marsh.1x1 -->* Marsh 29. may-ricepd.1x1 --> May rice paddies 30. nov-ricepd.1x1 --> November rice paddies 31. oct-ricepd.1x1 --> October rice paddies 32. pfloodplain.1x1* --> Permanent floodplain 33. ricepd.1x1 --> Rice paddies 34. sep-ricepd.1x1 --> September rice paddies 35. sfloodplain.1x1 --> Seasonal floodplain 36. swamp-marsh.1x1 --> Seasonal swamp/marsh 37. swamps.1x1 --> Swamp 38. swmiss.1x1 --> swamps/marshes, seasonality could not be determined 39. swpapr.1x1 --> April seasonal swamp/marsh 40. swpaug.1x1 --> August seasonal swamp/marsh 41. swpdec.1x1 --> December seasonal swamp/marsh 42. swpfeb.1x1 --> February seasonal swamp/marsh 43. swpjan.1x1 --> January seasonal swamp/marsh 44. swpjul.1x1 --> July seasonal swamp/marsh 45. swpjun.1x1 --> Jun seasonal swamp/marsh 46. swpmar.1x1 --> March seasonal swamp/marsh 47. swpmay.1x1 --> May seasonal swamp/marsh 48. swpnov.1x1* --> November seasonal swamp/marsh 49. swpoct.1x1* --> October seasonal swamp/marsh 50. swpsep.1x1 --> September seasonal swamp/marsh 51. total.1x1 --> Total natural wetlands * All values are zero for the subset but, files are included for sake of completeness. It is highly recommended that you review the original documentation for this data set for more specifics. There is some documentation on-line at http://www.scd.ucar.edu/isg/lana/wetlands/ . The complete, original documentation is an NCAR Technical Note (NCAR/TN-416+STR). The data files are in ASCII Grid format for ArcInfo. Each file contains a single ASCII array with integer values. Coordinates listed below are in decimal degrees. Rows 35 Columns 55 UpLeftX -85 UpLeftY 10 LoRightX -30 LoRightY -25 cellsize 1 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. Although ­9999 is listed as the nodata value it does not actually appear in the data. 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 AMAZON SUBSET ------------------------------------------------------------------- The original data were obtained and read following the directions in the original documentation. The data were converted to ASCII arrays and then imported into ArcInfo using the ASCIIGRID command. Using GRID ( a raster- or cell-based geoprocessing toolbox that is integrated with ArcInfo) the SETWINDOW command was used to define the subarea of interest. This subarea was defined by identifying the bounding coordinates as follows: x_min -85 y_min -25 x_max -30 y_max 10 The "snap_grid" option of the SETWINDOW command was used. This snaps the lower- left corner of the specified window to the lower-left corner of the nearest cell in the snap_grid and snaps the upper-right corner of the specified window to the upper-right corner of the nearest cell in the snap_grid. In this case the snap_grid is the original data grid. The purpose of this is to ensure the proper registration of the newly set analysis window. The command format used is as follows: SETWINDOW x_min y_min x_max y_max original_grid Once the window was set, creating the new grid was simply a matter of setting the new subset grid equal to the original grid. subset_grid = original_grid An ASCII array was created from the new subset grid using the GRID command GRIDASCII. file.dat = GRIDASCII(subset_grid) ------------------------------------------------------------------- LEGEND & ADDITIONAL SOURCES OF INFORMATION ------------------------------------------------------------------- All data values represent percentage area covered by the wetland category. The original data and documentation may be found at the following URL: http://www.scd.ucar.edu/isg/lana/wetlands/ ------------------------------------------------------------------- ORIGINAL DATA SET CITATION ------------------------------------------------------------------- L.M. Stillwell-Soller, L.F. Klinger, D. Pollard, and S.L. Thompson.1995. The Global Distribution of Freshwater Wetlands. TN-416STR, National Center for Atmospheric Research (NCAR), Boulder, Colorado, U.S.A. Available on-line at http://www.scd.ucar.edu/isg/lana/wetlands/ . ------------------------------------------------------------------- SUBSET DATA SET CITATION ------------------------------------------------------------------- LBA study area subset of, L.M. Stillwell-Soller, L.F. Klinger, D. Pollard, and S.L. Thompson.1995. The Global Distribution of Freshwater Wetlands. TN-416STR, National Center for Atmospheric Research (NCAR), Boulder, Colorado, U.S.A. Available on-line at ftp://www-eosdis.ornl.gov/data/lba_regional/soller_wetlands