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6- monthly NDVI average for Australia, 1 Dec 2012 to 31 May 2013 [1]. A vegetation index (VI) is a spectral imaging transformation of two or more image bands designed to enhance the contribution of vegetation properties and allow reliable spatial and temporal inter-comparisons of terrestrial photosynthetic activity and canopy structural variations.
Lastly, low, positive values represent shrub and grassland (approximately 0.2 0.4), while high values indicate temperate and tropical rainforests (values approaching 1). The normalized difference vegetation index (NDVI) is a widely-used metric for quantifying the health and density of vegetation using sensor data. It is calculated from ...
Regions with sparse vegetation and a low vegetation index are shown in tan. Based on measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite. Areas where there is no data are gray. [1] Vegetation is an assemblage of plant species and the ground cover they provide. [2]
2011 Enhanced vegetation index based on MODIS Terra data. The enhanced vegetation index (EVI) is an 'optimized' vegetation index designed to enhance the vegetation signal with improved sensitivity in high biomass regions and improved vegetation monitoring through a de-coupling of the canopy background signal and a reduction in atmosphere influences.
The index is given as: = (+) (+ +) where L is a canopy background adjustment factor. An L value of 0.5 in reflectance space was found to minimize soil brightness variations and eliminate the need for additional calibration for different soils. The transformation was found to nearly eliminate soil-induced variations in vegetation indices. [1]
A MODIS-derived photochemical reflectance index to detect inter-annual variations in the photosynthetic light-use efficiency of a boreal deciduous forest. Remote Sensing of environment, 98, 212-224. This biophysics -related article is a stub .
Low-cost index funds vs. ETFs vs. mutual funds. You can buy low-cost index funds as either an ETF or a mutual fund, and well-known indexes such as the S&P 500 will have both available. The list ...
Leaf area index (LAI) is a dimensionless quantity that characterizes plant canopies. It is defined as the one-sided green leaf area per unit ground surface area (LAI = leaf area / ground area, m 2 / m 2) in broadleaf canopies. [1] In conifers, three definitions for LAI have been used: Half of the total needle surface area per unit ground ...