Grass_Raster_NDVIService - This service is used to calculate a Normalized Difference Vegetation Index (NDVI).
NDVI is a standardized index allowing you to generate an image displaying greenness (relative biomass). This index takes advantage of the contrast of the characteristics of two bands from a multispectral raster dataset¡ªthe chlorophyll pigment absorptions in the red band and the high reflectivity of plant materials in the near infrared band.
An NDVI is often used worldwide to monitor drought, to monitor and predict agricultural production, to assist in predicting hazardous fire zones, and to map desert encroachment. The NDVI is preferred for global vegetation monitoring because it helps to compensate for changing illumination conditions, surface slope, aspect, and other extraneous factors (Lillesand 2004).
The NDVI transformation is computed as the ratio of the measured intensities in the red (R) and near infrared (NIR) spectral bands using the following formula:
NDVI = (NIR - red) / (NIR + red)
Operations:
ndvi - allows the user to calculate a Normalized Difference Vegetation Index (NDVI).
