Vegetation index

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.[2][3]

There are many VIs, with many being functionally equivalent. Many of the indices make use of the inverse relationship between red and near-infrared reflectance associated with healthy green vegetation. Since the 1960s scientists have used satellite remote sensing to monitor fluctuation in vegetation at the Earth's surface. Measurements of vegetation attributes include leaf area index (LAI), percent green cover, chlorophyll content, green biomass and absorbed photosynthetically active radiation (APAR).

VIs have been historically classified based on a range of attributes, including the number of spectral bands (2 or greater than 2); the method of calculations (ratio or orthogonal), depending on the required objective; or by their historical development (classified as first generation VIs or second generation VIs).[4] For the sake of comparison of the effectiveness of different VIs, Lyon, Yuan et al. (1998)[5] classified 7 VIs based on their computation methods (Subtraction, Division or Rational Transform). Due to advances in hyperspectral remote sensing technology, high-resolution reflectance spectrums are now available, which can be used with traditional multispectral VIs. In addition, VIs have been developed to be used specifically with hyperspectral data, such as the use of Narrow Band Vegetation Indices.

  1. ^ Cite error: The named reference NDVI was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Huete2002 was invoked but never defined (see the help page).
  3. ^ Carlos, Pérez Gutiérrez; Muñoz Nieto, Ángel Luis. Teledeteccion: Nociones y Aplicaciones (in Spanish). Spain. p. 144. ISBN 978-84-611-1613-3. Retrieved October 17, 2024.
  4. ^ Bannari, A.; Morin, D.; Bonn, F.; Huete, A. R. (1995-08-01). "A review of vegetation indices". Remote Sensing Reviews. 13 (1–2): 95–120. doi:10.1080/02757259509532298. ISSN 0275-7257.
  5. ^ Lyon, John G (1998). "A change detection experiment using vegetation indices". Photogrammetric Engineering and Remote Sensing: 143–150. CiteSeerX 10.1.1.462.2056.