Temporal and Spatial Distribution Pattern of Population at the South End of Hu Line in Recent 25 Years

The southern end of Hu Line mainly involves Sichuan and Yunnan provinces. In this paper, the spatial-temporal distribution pattern of population is analyzed by Standard Deviation Ellipse (SDE) and Exploratory Spatial Data Analysis (ESDA). The influence of human geography, natural geography and soil environmental factors on the spatial distribution of population and interactive interpretation are quantitatively calculated based on Geo-detector. The results show that: (1) the spatial distribution pattern of the population at the southern end of Hu Line is northeast-southwest. The spatial differences between the two sides are significant, the standard deviation ellipse turns weaker gradually, and the population distribution in southwestern China is balanced year by year. (2) The population concentration of the southern end of the Hu Line has been decreasing with the “U” type. Spatial aggregation occurs in high-density counties and surrounding high-density counties. The inaccessible regions appear in contiguous on the west side of the Hu Line. In less counties, there is a clear difference between the surrounding counties and the self, and the spatial distribution of the population tends to be balanced. (3) The dominant factors affecting the spatial distribution of population over the years are GDP density, nighttime lighting, road nuclear density, landforms, farmland production potential and elevation. (4) GDP density, road nuclear density, NDVI and NPP have a good interaction enhancement effect on population distribution. The first geographical intrinsic and the second geographic intrinsic evaluation index have the highest priority. The two-factor action intensity is greater than the single-factor action intensity, and the interaction type tends to be dominated by nonlinear enhancement. The spatial distribution of the population in the southern end of the Hu Line is mainly balanced by economic development and road construction. Night lighting, landform, farmland production potential, elevation, NDVI and NPP are potential factors for optimizing the population distribution at the southern end of the Hu Line