Measuring The Accessibility Of Public Green Spaces In Urban Areas Using Web Map Services

The important ecological and recreational functions of public green spaces for metropolitan regions have been increasingly recognized, especially in the last few decades in developing countries that experienced rapid urbanization at the cost of ecological land. This study developed a green accessibility index (GAI) that quantifies the efficiency of accessing different levels of public green spaces. The GAI used the improved estimation method by using web map services, which can acquire information such as optimized path choices and corresponding time-cost information in different trip modes. Taking Shanghai as a case, this study measured and mapped the accessibility of different types of public green spaces at the spatial resolution of 50 m. The results illustrated that the Central Activities Zone had the highest accessibility, whereas most rural areas beyond the Inner Ring Road had low accessibility, except for some parts dotted with several public parks. Overall, the accessibility decreased from the city core to the urban periphery within the Outer Ring Road. This study proposed an improved method to estimate the green space accessibility at a much finer scale with high accuracy, due to the advantages of the data provided by web map services. This method can be an effective tool in planning public green spaces, and can be adapted to plan other public service facilities.