Spatial heterogeneity of urban-rural integration and its influencing factors in Shandong province of China

Based on nighttime light data and statistical data, this study calculated the level of urban-rural integration (URI) of Shandong province, researched spatial heterogeneity of URI levels by local spatial autocorrelation analysis, Geodetector, and geographically weighted regression, and analyzed its influencing factors and spatial heterogeneity. The results concluded that: (1) The spatial pattern of urban-rural integrated level is consistent with the level of regional economic development in Shandong province. The level of URI is higher along the Qingdao-Jinan railway and along the coast, whereas the level is lower in southwest Shandong and northwest Shandong. (2) The cities of Yantai and Weifang are High-High cluster areas of urban integration, and Jining is a Low-Low cluster area. The spatial agglomeration characteristics are not significant in other cities. (3) Among the main factors affecting URI, the explanatory power of the rural population with high school or technical secondary school education or above, the area of urban construction land, and the secondary and tertiary industry GDP to the spatial pattern of URI in Shandong province are 73.58%, 62.08%, and 58.66%, respectively. As the key factors, spatial heterogeneity, such as north-south differences, southwest-to-northeast differences, and east-west differences, is evident.