Measuring spatial accessibility and supply-demand deviation of urban green space: A mobile phone signaling data perspective.

Abstract

The reasonable distribution of urban green space (UGS) is a topic that urban researchers have been exploring for a long time. Solving the imbalance between the supply and demand of UGS plays an important role in improving the health level of a city. This study examines the central urban area of Hefei as an example. We developed a modified Gaussian two-step floating catchment area method and used the path planning model of Gaode Map to evaluate the accessibility of UGS under different transportation modes and different time thresholds while integrating mobile phone signaling data. Additionally, a fine-scale analysis of the actual supply and demand relationship of UGS was conducted by integrating the accessibility evaluation results with the recreational situation of UGS to analyze the deviation of supply and demand to further discuss the spatial distribution equilibrium of UGS. The main conclusions are as follows. (1) The spatial distribution of UGSs in the central urban area of Hefei is uneven. Different time thresholds and different transportation modes have a significant impact on the UGS accessibility evaluation results. (2) With the increase in the time threshold or travel distance, the number of grids above the moderate accessibility level generally increases. The spatial distribution of the grids with moderate, high and highest accessibility level present different patterns of contiguous, clusters, and spots distribution. (3) After combining these results with the actual recreational situation of UGS, we found that the overall demand in the central urban area exceeds the supply at the 15-min threshold, while the overall supply exceeds the demand at the 30-min threshold. The grids with balanced supply and demand or more supply than demand have comprehensive parks with a moderate population density and strong road connectivity in the neighborhood. This study strengthens the data granularity and improves the accuracy of accessibility evaluation by integrating mobile phone signaling data with the path planning model of Gaode Map. Also, we evaluate the accessibility with multi-transport modes and different time thresholds, which can bring more practical guidance for optimizing the distribution of UGS.