9/9/97 - This readme files contains information about the following Humid Tropical Deforestation Project coverages that can be downloaded from our website: http://www.inform.umd.edu/tropical/index.html: This README file pertains to the file bol90v04.tar.Z. - 08/29/00 Updates since Version 0.1 ------------------------- 9/23/97 - Optimized for non-cloud classes in overlapping regions between scenes Version 0.4 08/29/00 - Holes in data set have been filled using improved methods and new data. These improvements have allowed for better registration of the images, greater accuracy in the classification and improved consistency. These improved methods will be applied to all images in the study area as time and funding permits. The year that each image used was acquired is now included as an item in the grid. (see bottom of this file for format) >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> The .tar file will unzip to 22.0 Meg. If you are operating on a Unix system type: prompt: gunzip bol90v04.tar.Z To expand the .tar file type: prompt: tar -xvf bol90v041.tar Winzip should be able to uncompress and 'untar 'this file also. Be aware that Windows will convert the dots before the final extension to underscores. You will need to edit the file name so that the underscore before the 'tar' extension is a '.' again. This will create an ESRI 'info' directory and a 'grid' directory. These directories will use up ~22 Meg in addition to the 22 Meg occupied by the .tar file. 'Grids' are viewable in ESRI's arcplot, grid and arcview. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> It is important to note that these are preliminary products. Field checking has been carried out in some areas, but is not complete. It is anticipated that revisions to this product will be progressively incorporated. Revisions will have higher version numbers. Details about the specific improvements in each version will be available as new versions are released. This ARC/INFO grid has a pixel size of 60 meters to a side. The output projection is Sinusoidal. An ARC 'describe' will list the relevent projection information, projection information is also included at the bottom of this file. The forest cover classes are under item VEG_CLASS in the .vat *****The mapped classes are:***** Class 1 Forest: Forest refers to primarily closed canopy humid tropical forest, and includes cloud forest. Class 4 Water: Water includes lakes, rivers, and oceans if applicable. Water also includes areas that are inundated by dam/reservoir projects. Swamps may also appear as water. Class 8: Degraded Forest: (AFRICA ONLY) Degraded forest are areas in Africa where human activity is visible. Due to the landuse patterns, including selective logging, differentiation between deforestation/revegetation/agriculture is not currently possible. Generally discernible from natural forest, the true extent may only be determined through ground verification. Class 9: Nonforest: Nonforest includes areas such as cerrado, savanna, rock outcrops, high elevation brush/scrub vegetation, sand dunes or spits/bars, predominantly deciduous seasonal forest, snow fields, heavily inundated flood plains with sparse vegetation. For this release product, areas that fit the definition of class '8' are included in the 'Nonforest' category. Class 999/0: These are no data pixels where there was no good, cloud free imagery available. As we continue to search and obtain replacement data, future versions of the coverages will have areas of 999 replaced by the correct vegetation class. Areas of 0 are poor quality subareas within an image where we were unable to confidently determine the vegetation type. Clouds, cloud shadow and terrain shadow have also been mapped to this class. *****Items in the .VAT***** COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME INDEXED? 1 VALUE 4 10 B - Indexed 5 COUNT 4 10 B - - 9 BOL90DATE 4 16 B - - 13 VEG_CLASS 4 16 B - - VEG_CLASS corresponds to the definitions listed above. BOL90DATE is the year that pixel data was acquired. *****Projection Information***** The Peru and Bolivia grids are in sinusoidal projection with: longitude of central meridian is -60 00 00 false easting is 3000000 false northing is 3000000