Logistic regression 1 All predictor variables are z-transformed.
All predictor variables were used in the analysis.
All predictor variables were gridded at 30-m spatial resolution.
Descriptive statistics of all predictor and control variables are shown in Table 5.
We scale all predictor variables to be able to compare their effect.
(DOCX 27 KB) 13717_2012_14_MOESM2_ESM.docx Additional file 2 Bivariate relationships between all predictor variables.
For the two multivariable linear regression models, the total variance accounted by all predictor variables were computed.
Multivariable linear regression models were used to examine the simultaneous association between all predictor variables and outcomes.
We analyzed only one model, in which all predictor variables were included and tested at the same time.
Consequently, two regression tree-based models were developed using: (1) only the seven mineral soil topographic variables, and (2) all predictor variables (mineral soil topography and surficial deposits).
