Development overview and some thoughts on geographic synthesis

The geographical system can be recognized as a giant complex system, and the comprehensive study of geography is of great importance in understanding the complex geographical system as a whole. With the rapid development of geographical research, geographic synthesis has become the fundamental task of geographical innovation and breakthrough in the new era. The development of theoretical methods of geographic synthesis has become a critical way to prevent the hollowing out of geography and establish the core theory of geography. However, the conventional practice of geographic synthesis prefers to "divide first and synthesize last", which formed the dilemma of "easy to divide but difficult to synthesize". Therefore, the system of geographic synthesis method requires further exploration. From the perspective of geographical cognition, analysis, and synthesis, this paper summarized the state-of-art research and methods of geographic synthesis, identified the root causes that hinder the development of geographic synthesis methods, and puts forward a new conception of developing the method of geographic synthesis research based on "geographic modal". Compared to the modal and modal analysis methods in the domain of structural systems, geographic modal, as the description form and expression mechanism of regular cognition of the geographical system, is a higher-level abstract carrier than geographical elements and processes. This paper analyzed the characteristics and composition of geographic modal. Based on the regular geographical cognition of spatial patterns, evolution processes, and interaction mechanisms, the integrated and systematic cognition of the geographical system can be formed by the organic aggregation and orderly iteration of multilevel geographic modals. This strategy is expected to benefit the comprehensive research and model reconstruction of the geographical system. This paper aims to sketch a full-stage pathway of geographic synthesis research to address two scientific problems: (1) How to use the overall characteristics of geographic modal to construct cognitive models and representation methods of geographic synthesis, and (2) how to construct detection, analysis and aggregation methods of geographic modal based on the structural characteristics of geographic modal. The research method of geographic synthesis based on the geographic modal will open a two-way channel from fragmental geographical cognition to comprehensive geographical cognition. In addition, modal-based geographic synthesis can be employed to construct new methods to step from geographical data to geographical law and further to comprehensive geographical cognition. This study potentially promotes the collaborative evolution of theories and methods of geographic synthesis, and it is also expected to facilitate the development of geographic synthesis research.