Fig. 4: Mean decrease of RSS of the features (regions) in RF and GBDT.

Note: Raw data is normalized to the interval (0,1) to adjust the units in which the data is presented. Figure 4 shows the importance of the variables for various regions. The ranking was roughly the same across regions in the RF and GBDT. Overall, variable importance for regions was generally high in Jeonnam, Chungnam, Gyeongbuk, Ulsan, and Gyeonggi.