Does urban renewal enhance urban vitality? A case study of Nanjing, China, using multidimensional data

Urban renewal is critical for improving city functionality after reaching a certain urbanization level. Although urban vitality is an effective indicator of the spatiotemporal effects of urban renewal, significant gaps exist in using cross-sectional data to assess the effectiveness of urban renewal, especially regarding changes in the socioeconomic vitality of cities. In addition, no evaluation framework exists to identify issues and inform future planning improvements. Therefore, this study constructs a comprehensive evaluation framework based on the vitality index to assess the impact of 57 urban renewal projects on multidimensional changes in urban vitality in Nanjing from 2015 to 2019. Multidimensional dynamic data, such as 1,174,473 Weibo tweets in 2015 and 1,318,844 in 2019, 20 population density heat maps, and 353,231 facility data in 2015 and 638,381 in 2019, are used to establish the framework. Although urban renewal effectively increased population density and improved facility distribution, with an average increase in the vitality index of 1.375 and 0.878, respectively, it failed to improve residents’ satisfaction, which decreased by 0.386, adversely affecting residential urban renewal projects. The analysis of the factors influencing urban renewal performance shows that location, increase in floor area (Additional Gross Floor Area), policies, and their implementation are crucial for increasing urban vitality. These findings underscore the necessity of prioritizing residents’ needs and expectations during urban renewal. Furthermore, our framework provides urban planners and decision-makers with new insights and practical methodologies on the effective implementation of urban renewal projects to ensure sustainable urban development.