@article{fdi:010044192,
  title = {{C}ontinuum removal versus {PLSR} method for clay and calcium carbonate content estimation from laboratory and airborne hyperspectral measurements},
  author = {{G}omez, {C}{\'e}cile and {L}agacherie, {P}. and {C}oulouma, {G}.},
  editor = {},
  language = {{ENG}},
  abstract = {{R}eflectance spectroscopy provides an alternate method to classical physical and chemical laboratory soil analysis for estimation of a large range of key soil properties. {T}echniques including classical chemometrics approaches and specific absorption features studies have been developed for deriving estimates of soil characteristics from visible and near-infrared ({VNIR}, 400-1200 mm) and shortwave infrared ({SWIR}, 1200-2500 nm) reflectance measurements. {T}his paper examines the performances of two distinct methods for clay and calcium carbonate ({C}a{CO}3) content estimation (two key soil properties for erosion prediction) by {VNIR}/{SWIR} spectroscopy: i) the {C}ontinuum {R}emoval ({CR}) has been used to correlate spectral absorption bands centred at 2206 and 2341 nm with clay and {C}a{CO}3 concentrations and ii) the partial least-squares regression ({PLSR}) method with leave-one-out cross-validation, which is a classical chemometrics technique, has been used to predict clay and {C}a{CO}3 concentrations from {VNIR}/{SWIR} full spectra. {W}e tried to respond to the question "should we use all bands in the 400-2500 nm range or should we focus our analysis on selected spectral absorption bands to determine soil properties from reflectance data?" {I}n this paper, the {CR} and {PLSR} methods were applied to {VNIR}/{SWIR} laboratory and airborne {HYMAP} reflectance measurements collected over the {L}a {P}eyne {V}alley area in southern {F}rance. {T}his study shows that the performance of both techniques is dependent on the spectral feature for the soil property of interest and on the level data acquisition (lab or airborne) face to the instrument specifications. {W}hen airborne {HYMAP} reflectance measurements are used, the {PLSR} technique performs better than the {CR} approach. {A}s well, when the soil property of interest has no well-identified spectral feature, which is the case of clay, the {PLSR} technique performs better than the {CR} approach. {I}n this last situation, {PLSR} is able to find surrogate spectral features that retain satisfactory estimations of the studied soil properties. {H}owever, parts of these spectral features remain difficult to explain or relate to area-specific correlations between soil properties, which means that extrapolation to larger pedological contexts must be envisaged with care. {I}n the near future, {VNIR}/{SWIR} airborne hyperspectral data processed by the {PLSR} technique will allow for accurate mapping of clay and {C}a{CO}3 contents, which will contribute significantly to the digital mapping of soil properties.},
  keywords = {{A}irborne hyperspectral data ; {VNIR}/{SWIR} spectroscopy ; {C}lay ; {C}alcium ; carbonate ; {C}ontinuum removal ; {P}artial least square regression},
  booktitle = {},
  journal = {{G}eoderma},
  volume = {148},
  numero = {2},
  pages = {141--148},
  ISSN = {0016-7061},
  year = {2008},
  DOI = {10.1016/j.geoderma.2008.09.016},
  URL = {https://www.documentation.ird.fr/hor/fdi:010044192},
}