Fig. 4: Predicted map of microplastics (MPs) in inland waters based on random forest.
From: Quantitative assessment on the distribution patterns of microplastics in global inland waters
a Global prediction map of MP abundance, and b latitudinal pattern of MP abundance (red line indicates the locally weighted regressions and yellow ribbon spans the range between the 5% and 95% quantiles). The predicted value was the average value of the results of 100 iterations of random forest model. Predicting MP abundance after log transformation was reserved to draw the map to avoid skewed distribution of the MPs values, while the values of the map need to log-transformed and then added to 1 for viewing. The spatial resolution of grid cells was 3 arcmin-by-3 arcmin.
