Resumo

PAZ PELLAT, Fernando et al. Scopes and limitations of spectral vegetation indexes: theoretical framework. Terra Latinoam [online]. 2014, vol.32, n.3, pp.177-194. ISSN 2395-8030.

Vegetation indices (VI) have been proposed as an indirect way of measuring biophysical vegetation variables, based on spectral data obtained with remote sensing. We analyzed the VI from a theoretical perspective considering the interactions of first and second order, as well as the radiative transfer problem present in homogenous and heterogeneous media. Iso-vegetation curve patterns (leaf area index, LAI) were developed to be used as reference during the VI revision. Iso-LAI curves were parameterized in the red (R) and near infrared (NIR) space and the use of other spectral spaces was analyzed. The iso-LAI curve patterns did not change regardless of atmospheric effects or the use of spectral spaces different from R and NIR. Additionally, the sun-sensor geometry effects were also considered for their standardization in such a way that the curve patterns were invariant. The theoretical framework presented in this paper, iso-LAI patterns, allows generalized analysis of any type of VI.

Palavras-chave : vegetation indices; remote sensing; iso-LAI curve patterns; spectral spaces; radiative transfer.

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