Evolution of value addition process for generation of Normalised Difference Vegetation Index (NDVI) product – A case study

Vegetation indices are widely used for global monitoring of vegetation conditions and are used in products displaying land cover and their changes. Normalized Difference Vegetation Index (NDVI) quantifies vegetation by measuring the difference between near-infrared (the wavelength which vegetation strongly reflects) and red light (the wavelength which vegetation absorbs). NDVI is being used in several applications such as agriculture, for precision farming and to measure biomass. In forestry, NDVI is used to quantify forest supply and leaf area index. NDVI is also a good indicator of drought. To monitor the crop growth and to estimate the crop acreage, drought, Mahalanobis Crop forecasting Centre (MNCFC) uses NDVI products supplied by NRSC from Resourcesat-2/AWiFS data as one of the inputs. The products are delivered at a spatial resolution of 56m in Geo-tiff format with Albers Conical Equal Area projection. The requirements of MNCFC and the value addition processing at NRSC have evolved from 2012 onwards. It started by supplying fortnightly one full India mosaic by processing 5 days data to generate the maximum value composite for cloud free pixels by processing every day data to generating 6 full India NDVI mosaics in a month. The paper presents the evolution of user requirements and the processing methodologies from start of the product supply in the year 2012 to till date by bringing out the salient details about the automation of the processes that has taken place along with comparison of the product generated using Landsat 8 and Modis NDVI data sets.