Visible spectrometric indices of hematite (Hm) and goethite (Gt) content in lateritic soils: The application of a Thematic Mapper (TM) image for soil-mapping in Brasilia, Brazil
作者:
J. Madeira,
A. Bedidi,
B. Cervelle,
M. Pouget,
N. Flay,
期刊:
International Journal of Remote Sensing
(Taylor Available online 1997)
卷期:
Volume 18,
issue 13
页码: 2835-2852
ISSN:0143-1161
年代: 1997
DOI:10.1080/014311697217369
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
Data on mineralogy and diffuse reflectance spectra, obtained from 56 samples of Brazilian lateritic soils, were used to establish quantitative relationships between spectral parameters and iron oxides contents (hematite and goethite). A redness index RI H calculated from Helmholtz chromatic co-ordinates ( lambda d, P e, Y) and correlated to hematite content is found. A good estimate of the ratio Hematite/ (Hematite + Goethite) is given by the dominant wavelength lambda which takes into account a large proportion of the tint detected on the soil sample. Based on these laboratory results, radiometric indices were elaborated by combining only those parts of the visible spectrum that correspond to Thematic Mapper (TM) channels: (i) a hematite index I Hm to estimate hematite concentration; and (ii) a ferric index I Fe to estimate the ratio hematite/(hematite goethite). The hematite index, applied to a TM image of the area around Brasilia, allowed hematite contents in the surface horizons of lateritic soils to be mapped accurately.
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