Geography is a science that investigates mutual relationships and interactions between natural and human elements on the earthy s surface, is a science of the covergence between natural science and social science. There are total three basic rules in geography:
    Firstly, rule of regional differentiation, including latitudinal zonality, meridional zonality, altitudinal zonality and none zonality.
    Secondly, rule of regional complex, including rule of distance decay, rule of regional systems.
    Thirdly, rule of regional development, including the periodic law of geographical environment and rule of the period of man-land relationship.