A Review of Vegetation Indices and Their Importance for Agricultural Observation

Abstract

Satellite and airborne remote sensing makes it possible to map vegetation cover and follow its changes across large regions. Vegetation indices (VIs), which are simple formulas built from a few spectral bands, offer a practical way of carrying out such assessments. This paper reviews basic and advanced indices together with the confounding factors that influence them: soil brightness, soil colour, atmospheric conditions, vegetation status and crop water status. Schemes for classifying the indices are described, reported relationships between VIs and forest biomass are summarised, and a filtering approach that extracts seasonal signals of NDVI and PRI from ground-based sensors is presented as a useful tool for crop monitoring.