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.geog.umd.edu/tropical/main.html: This README file pertains to the file peru80.16k.v1.41.e00.Z. - 1/13/00 Updates since Version 1.1 ------------------------- 9/24/97 - Optimized for non-cloud classes in overlapping regions between scenes Version 0.4 9/14/99 - 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 classes have been simplified to more closely match the 90s product. Version 0.4.1 1/13/00 - Errors caused by resampling have been corrected. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> The file peru80.16k.v1.41.e00.Z will uncompress to 1.2 Meg. If you are operating on a Unix system type: prompt: uncompress peru8016k.v1.1.e00.Z Winzip should be able to uncompress 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 'e00' extension is a '.' again. To expand this file you will need to type the following at the Arc prompt; ARC: import grid peru80.16k.v1.41.e00 This will create an Arc/Info grid ~1 Meg in size. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 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. The base resolution for this ARC/INFO grid was a pixel 57m to a side. The 80s maps are being distributed as a ~16Km pixel side summary of the base map. The output projection is Sinusoidal. An ARC 'describe' will list the relevent projection information, it is also included at the bottom of this file. The items within the .vat are defined below the class definitions. The general 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 21: Questionable forest: Small areas, primarily in mountianous regions, that we believe are forest according to our definition but we need field validation to verify this. Class 999/0: These are no data pixels. In these areas 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. 16 KM Product: ---------------- The 80s epoch is being provided in a 16 KM(per grid cell side) resolution product. The 90s epoch data will be released in additional higher resolution formats. All percentages and area measurements are derived from the full resolution coverages. The file is the product of "export" from Arc/Info version 7.0.3 (copyright ESRI, Inc., Redlands, Ca). In order to display the .e00 file, you must first use Arc "import" to recreate the coverage. The usage is: Arc:import grid peru80v01.e00 Variables for each 16 km grid cell: Percent_1: The percentage of forest within the map cell. Percent_4: The percentage of water within the map cell. Percent_8: (Africa *ONLY*) The percentage of apparent human disturbance. Percent_9: The percentage of non-forest within the map cell. Percent_999: The percentage of 999 in the map cell. 999 is 'Data not Available' Areas are calculated based on the pixel size (57 meters for 80s and 30 meters for 90s) and the number of pixels for a particular class within the map cell. Units are square meters. Forestarea: The area covered by humid tropical forest. Waterarea: The area occupied by water. Degforarea: *AFRICA ONLY* The area of apparent human caused forest degradation. Nonforarea: The area covered by non-forest vegetation. DATAUNAVAIL: The area of unavailable data *****Projection Information***** The grids are in sinusoidal projection with: longitude of central meridian is -60 00 00 false easting is 3000000 M false northing is 3000000 M