@incollection{fdi:010072189,
  title = {{U}sing legacy soil data for standardizing predictions of topsoil clay content obtained from {VNIR}/{SWIR} hyperspectral airborne images},
  author = {{G}omez, {C}{\'e}cile and {G}holizadeh, {A}. and {B}oruvka, {L}. and {L}agacherie, {P}.},
  editor = {},
  language = {{ENG}},
  abstract = {{M}apping of topsoil properties using {V}isible, {N}ear-{I}nfrared and {S}hort {W}ave {I}nfrared ({VNIR}/{SWIR}) hyperspectral imagery requires large sets of ground measurements for calibrating the models that estimate soil properties. {T}o avoid collecting such expensive data, we proposed a procedure including two steps that involves only legacy soil data that were collected over and/or around the study site: 1) estimation of a soil property using a spectral index of the literature and 2) standardisation of the estimated soil property using legacy soil data. {T}his approach was tested for mapping clay contents in a {M}editerranean region in which {VNIR}/{SWIR} {AISA}-{DUAL} hyperspectral airborne data were acquired. {T}he spectral index was the one proposed by {L}evin et al (2007) using the spectral bands at 2209, 2133 and 2225 nm. {T}wo legacy soil databases were tested as inputs of the procedure: the {F}ocused-{L}egacy database composed of 67 soil samples collected in 2000 over the study area, and the {N}o-{F}ocused-{L}egacy database composed of 64 soil samples collected between 1973 and 1979 around but outside of the study area. {T}he results were compared with those obtained from 120 soil samples collected over the study area during the hyperspectral airborne data acquisition, which were considered as a reference. {O}ur results showed that: 1) the spectral index with no further standardisation offered predictions with high accuracy in term of coefficient of correlation r (0.71), but also high bias (-414 g/kg) and {SEP} (439 g/kg), 2) the standardisation using both legacy soil databases allowed an increase of accuracy (r = 0.76) and a reduction of bias and {SEP} and 3) a better standardisation was obtained by using the {F}ocused-{L}egacy database rather than the {N}o-{F}ocused-{L}egacy database. {F}inally, the clay predicted map obtained with standardisation using the {F}ocused-{L}egacy database showed pedologically-significant soil spatial structures with clear short-scale variations of topsoil clay contents in specific areas. {T}his study, associated with the coming availability of a next generation of hyperspectral {VNIR}/{SWIR} satellite data for the entire globe, paves the way for inexpensive methods for delivering high resolution soil properties maps.},
  keywords = {{TUNISIE} ; {ZONE} {MEDITERRANEENNE}},
  booktitle = {{ISPRS} {G}eospatial {W}eek 2015},
  numero = {{XL}-3/{W}3},
  pages = {439--444},
  address = {{G}{\¨o}ttingen},
  publisher = {{C}opernicus},
  series = {{T}he {I}nternational {A}rchives of the {P}hotogrammetry, {R}emote {S}ensing and {S}patial {I}nformation {S}ciences},
  year = {2015},
  DOI = {10.5194/isprsarchives-{XL}-3-{W}3-439-2015},
  ISSN = {2194-9034},
  URL = {https://www.documentation.ird.fr/hor/fdi:010072189},
}