With the selected seven variables, we found that the unique
effects of the three groups of variables on urban expansion varied
with time (Fig. 4). The unique effects of physical factors and
neighborhood factors both decreased, while the effect of socioeconomic
factors increased along with the urbanization process
(Fig. 4). During the period of 1972e1984, the unique effects of the
physical factors were the highest, followed by socioeconomic
factors and neighborhood factors. After that, the socioeconomic
factors independently explained the most variance in urban
expansion (Fig. 4).