## 6 Discussion  
The concept of urban vitality, rooted in essential human activities, is complex and multidimensional, and its intensity cannot be fully measured or represented by relying on a single data source alone [54]. The integration of multi-source data enables urban planners and policymakers to conduct a more evaluation of urban vitality [55]. Combining Baidu heat map data, urban points of interest and night light images can more accurately depict the intensity of human activities within urban areas, thereby facilitating a deeper understanding of the spatial pattern of urban vitality distribution. Unlike earlier studies that relied on a single data source to analyze variations in urban vitality intensity, this research integrates multiple big datasets to quantitatively evaluate the spatial vitality of Qingdao's central area, which provides a robust foundation for comprehensively exploring the multidimensional spatial driving factors influencing urban vitality. Urban development requires the coordinated interaction of multiple spatial dimensions. The spatial variation in urban vitality is closely associated with diverse urban  
Figure 10: Descriptive statistics of MGWR coefficients for urban vitality at the block scale. components across different spatial scales [56]. This study identifies that commercial facilities accessibility and cultural and leisure facilities accessibility have a significant influence on urban vitality, corroborating previous research [28]. This study, consistent with the findings of [PERSON] et al. [33] and [PERSON] et al. [32], indicates that densely populated urban cores exhibit both positive and negative effects on urban vitality. At the block scale, a negative correlation between population density and urban vitality is observed, which aligns with the findings of [PERSON] et al. [57]. Therefore, it is crucial to plan for mixed land use, appropriately infill available spaces to create more opportunities and reasonably allocate urban facilities. In addition, incorporating the concept of the 15 min city can enhance the accessibility of urban amenities, thereby stimulating the growth of active travel modes such as walking and cycling, achieving a compact city form, and promoting a win-win situation for urban vitality and sustainable transportation [58,59]. Future research should further explore the relationship between urban vitality planning and active travel, to understand how these can form a virtuous cycle and promote sustainable urban development. Similarly, [PERSON] et al. observed that building height consistently exerts a positive influence on urban vitality, aligning with the results of the present research [27]. Excessive building heights may lead to a decline in residential comfort. Dense clusters of high-rise buildings are particularly prone to creating street canyon effects, which can hinder the dispersion of air pollutants [60] and intensify the urban heat island effect [61], resulting in adverse microclimatic conditions. These factors may ultimately have a negative impact on pedestrian comfort and outdoor activities, thereby indirectly diminishing urban vitality. Thus, increasing building heights to enhance urban vitality should be accompanied by reasonable planning to ensure sustainable improvements. However, not all factors exert uniform effects across spatial scales. For instance, excessive functional diversity and randomness were found to impede urban vitality, in agreement with earlier findings [62,63]. This study reveals that the greening rate exhibits a negative influence on urban vitality, which is consistent with the findings of [PERSON] et al. [64] and [PERSON] et al. [33]. Furthermore, metro accessibility exhibits an overall negative correlation with urban vitality at the block scale, suggesting that proximity to metro stations facilitates population aggregation and increased flow, as reported by previous studies [65]. These findings highlight the need for a comprehensive and multidimensional approach to enhancing urban vitality.