|U.S. Department of Agriculture
National Agricultural Statistics Service
Research and Development Division
Starting in 1999, the images for the entire US (NDVI, Ratio/Previous, and Ratio/Median - as available) for a given period are also being created in an Adobe PDF format. The PDF format allows for browsing user-defined areas and zooming in more closely to view them. The PDF files were created with 256 colors for printing on 8.5"x11" size paper. Anyone with a standard Acrobat reader will be able to view the files. The PDF images have a higher resolution that the GIF files, but are also much larger; PDF images may be as large as 2.0MB.
Starting with the 2004 season, the entire US NDVI composite for each period has been or will be converted to a GeoTiff image for use in geographic information systems software. (2011 will be loaded as available). Due to the size of these files (13-14 MB), each GeoTiff has been compressed into a "Tar" format file for easier download (4-5 MB). Select the "Download" option above to access these tiff files. Standard products are selectable below:
For more information about this topic or about the NASS Spatial Analysis Research Section (SARS), contact the GeoSpatial Information Branch at HQ_RDD_GIB@nass.usda.gov.