Inversion Of Soil Geochemical Information In Yingjiang County Based On GF-5 Satellite Data

In this paper,an area of 100km² in Yingjiang County was taken as the study area.Through spectral transformation of the GF-5,the correlation between spectral value and soil geochemical information content value was established by combining the measured values of soil geochemical information.The characteristic spectral bands of soil geochemical information such as P,Si O₂,Mg O,K₂O,Fe₂O₃ and Al₂O₃ were extracted,and the inversion models of soil geochemical information contents were established by using the methods of curve regression analysis,multiple regression analysis and partial least squares regression analysis,and the model accuracy among different models was compared.The spatial distribution characteristics of soil geochemical information were analyzed by selecting the remote sensing inversion model of soil geochemical content,and the geological origin of this area was analyzed.The main achievements are as follows:(1)Based on the research in GF-5 of the original spectrum for spectrum transform,such as first order differential,logarithmic reciprocal,continuum removal,and combined with P,Si O₂,Mg O,K₂O,Fe₂O₃,Al₂O₃,such as soil geochemical information measured values,analysis the soil geochemical information and the correlation between the spectral values.By comparing and analyzing the results of different spectral transformation methods,it is concluded that the continuum removal method has the most significant improvement in the relationship between the content of P,Si O₂,Mg O and K₂O information and spectral reflectance,and the correlation improvement effect of Fe₂O₃ and Al₂O₃ information treated by logarithmic reciprocal method is the best.(2)In this study,spectral inversion models of soil geochemical information such as P,Si O₂,Mg O,K₂O,Fe₂O₃ and Al₂O₃ in Yingjiang area were established by using curvilinear regression analysis,multiple regression analysis and partial least squares regression analysis respectively.The model accuracy was evaluated by using validation samples to select the best model.The final determination coefficient R² of each soil geochemical information inversion model is greater than0.9.Using the inversion model,the contents of soil geochemical information in the study area were retrieved,and the spatial distribution characteristics of soil geochemical information were analyzed.(3)Through the analysis of the geological origin of the study area,it is concluded that the quartz and feldspar in the top of the Holocene in the middle of the study area make the content of soil geochemical information such as Si O₂ and K₂O higher than that in other areas;The clay layer in Pleistocene strata in the southeast of the study area has a great influence on the content of soil geochemical information such as Si O₂,K₂O and Al₂O₃.The contents of Mg O,Fe₂O₃ and Al₂O₃ in the study area are relatively high due to the influence of plagioclase,biotite,calcite and dolomite in the Gaoligongshan Group in the northwest of the study area.