Objective The Dianchi Lake Basin is a typical sample of plateau lake-type human – water interaction, and its settlement system evolution contains the spatial code of human settlements adapting to hydrological changes. Through integrating the spatio-temporal analysis of topography and geospatial analysis, this research reveals the formation mechanism of settlement pattern driven by human – water relationship, explores the evolution characteristics of settlement pattern in the Dianchi Lake Basin, and provides methodological innovation for interdisciplinary research of human settlement environment science.

Methods 1,332 toponyms of historical settlements are selected as the research objects, and the nature – human binary semantic analysis framework is constructed by using the method of geographical language analysis. In order to explore the spatial distribution types of toponymic settlements, the closest proximity index and geographical concentration index are used for analysis. In order to further reflect the agglomeration distribution law of settlements, the distribution location and law of settlements are analyzed by nuclear density analysis. In addition, the buffer zone analysis method is used to further explore the spatial correlation between settlement distribution and hydrological characteristics, and the geographical detector is used to carry out relevant research to explore the spatial mechanism with respect to the impact of geographical factors on toponym pattern. Toponyms in the Dianchi Lake Basin are formed in the interaction process of human – water relationship. The research on natural toponyms reveals that geomorphic environment and hydrological environment are the basis of human settlement activities. Seven indexes are selected to construct the index system of driving factors for the spatial pattern of settlement, with factor detection and interaction detection being adopted for specific analysis. Through the historical geographic information corroboration, the research reveals the change law of human settlement environment at a 1,000-year scale.

Results 1) The settlements in the Dianchi Lake Basin as a whole and all kinds of toponyms are clustered; the distribution of settlements shows a “two-center” structure with obvious water system agglomeration characteristics, revealing the process of shifting the focus of human settlement activities under the trend of “water retreating and people advancing”, which is realized through the major events of “human – water relationship” such as the cultivation of farmland by the Institute of Sanitation, the construction of water conservancy, and the expansion of irrigation areas. The north alluvial fan area relies on the Panlong River system to form the administrative and economic complex center, while the southeast lakeside plain retains the characteristics of early fishing and farming civilization, forming the geographical differentiation law of “south fishing and north farming”. The center of gravity of human settlement activities has shifted from the southeast bank to the north bank, and the benign control of hydrological environment has been realized in the gradual cumulation human settlement behavior. 2) The interactive effect of elevation and river network density is the key factor leading the evolution of settlement pattern in the Dianchi Lake Basin: In short-term scale, elevation and river network density are interlocking, and the hydraulic engineering reduces the riverbed elevation and expands the alluvial fan area, which significantly enhances the settlement carrying capacity in the low altitude area and affects the spatial pattern of settlement after Yuan Dynasty; in the long term, from the dual clues of “hydrological constraint” to human – water interaction, the significant spatial coupling of the migration trajectory of the settlement center of gravity and the retreat process of the lake shoreline confirms the characteristics of the phased transformation of the relationship between human and water, and realizes the paradigm shift from “choosing to live near water” to “controlling water for better habitation”.

Conclusion The combination of toponymy and spatial analysis provides an innovative path for the interdisciplinary research on human settlement science. By constructing a coupling analysis framework of toponym semantics and spatial attributes, this research confirms the “spatio-temporal code” function of toponym in the process reconstruction of human settlements, and the capability to analyze multi-source heterogeneous data based on the aforesaid function provides a new analytical methodology for the research on watershed human settlements. The changing vein of human settlement environment with human – water relationship as the main line continues to this day. At present, the Dianchi Lake Basin is the key area of Kunming’s urban planning and construction, and the planning measures to strengthen the ecological barriers of rivers and lakes are of great importance to the ecological security pattern of human settlements in the Dianchi Lake Basin. At the same time, as a reflection of folk style and deep historical and cultural heritage, toponyms contain the relationship between man and nature in different stages. Therefore, in urban construction, the search of traditional toponyms, the mining of cultural connotations toponyms, and the reasonable naming of new toponyms are not only conducive to the protection of the intangible cultural heritage of traditional toponyms, but also play an important role in following the law of urban development and realizing the harmonious relationship between people and water.