Village Level Vegetation Monitoring Using Resourcesat Data
Status of vegetation at village level plays an important role to assist policy makers as a decision support feature. Space Applications Centre, SAC/ISRO Ahmedabad has developed an automated system to compute village level NDVI through Visualisation of Earth observation Data and Archival System (VEDAS). The vegetation status of an area is measured by NDVI - Normalised Difference Vegetation Index, a numerical indicator calculated using reflectance in Red and Near Infrared (NIR) channels of electromagnetic spectrum. This information helps the planners and decision makers to evaluate performance of vegetation growth at village level, in turn assess the crop insurance claims by the farmers.
Resourcesat AWiFS data over Haryana acquired from Jan 01, 2016 till date by HARSAC, Hisar were used for the study. The data with a spatial resolution of 56 meters in four spectral bands and temporal resolution of 5 days were acquired which were automatically processed for NDVI. Depending upon user requirement, 1 to 15-day dynamic moving max NDVI composite, corresponding to vegetation status at clearest atmospheric condition and/or nadir looking geometry can be generated. Village, taluka and district level boundary of Haryana was overlaid. A graphical view of temporal profile of village level average NDVI can be seen on Vegetation Monitoring module of VEDAS. On-the-fly difference image of the two dates / seasons can also be seen for the comparison. Geo-spatial query (Range analysis) can also be performed giving range of dates and NDVI values of interest.
Visualization of temporal NDVI at village level is helpful in determining current season vegetation status vis-à-vis its situation in previous years. Such interpretation, along with corresponding environmental status of soil moisture and weather conditions can be a supportive tool to strengthen objective data based decision support system to assist claims of farmers for crop insurance. Tabular data in formats such as csv, xls, pdf, jpeg is also downloadable by users for further inspection and analysis.
ISRO has successfully developed a system, which provides village level statistics of NDVI (indicator of vegetation status) using AWiFS sensor data on-board Resourcesat. It is useful in determining current season vegetation status in comparison with that of previous years.
NDVI Image of August 29, 2017
Dynamic NDVI Composite Generation: August 29, 2017 ± 5 Days
Dynamic NDVI Composite Generation: August 29, 2017 ± 10 Days
Comparison of Village level NDVI Profile Using AWiFS Data
NDVI Image of Nov 2017 (Left); Nov 2016 (Centre); Difference Image (Right)