Abstract: In the spring of 1996 with funding from the National Aeronautics and
Space Administration (NASA), KARS began producing a bi-weekly map
series called the GreenReport. that measures vegetation conditions
across the Unites States. The GreenReport is produced using
Normalized Difference Vegetation Index (NDVI ) images compiled at EROS
Data Center from Advanced Very High Resolution Radiometer (AVHRR)
... imagery. Using these images, four bi-weekly maps are created to show
current vegetation greenness:

- Greenness Map - Illustrates crop/vegetation conditions and state
of development

- Difference Map 1 - Compares crop/vegetation progress to the
previous bi-weekly period

- Difference Map 2 - Compares crop/vegetation condition and
progress to the previous year

- Difference Map 3 - Compares crop/vegetation condition and
progress to a 10-year average

GreenReport map sets can be used like any crop report that describes
regional crop conditions. The advantage of displaying crop information
(derived from satellite data) in map form is that the precise
locations of growing events can be identified. The GreenReport
combines current satellite data with historic data to present a more
complete picture of crop condition and progress. GreenReport map sets
can accurately show areas were crops are progressing or doing poorly
from one period to the next, and can compare crop progress and
condition to the previous year and to average conditions. When used
together, the map sets can be used as a tool for understanding crop
development throughout the growing season and from year to year.