As digital technologies profoundly reshape our urban morphology, this 2025 Special Issue of Urban Design on the “Digital City” arrives as a timely academic intervention. This edition centers on the digital realm as a core catalyst, aggregating cross-disciplinary research to chart the ontological transition from mere tool-based innovation toward a systemic driver for spatial innovation and urban design.
       In our invited research section, Ye Yu’s team systematically delineates the trajectories of technological evolution, proposing a robust pathway from fragmented tools toward the synthesis of intelligent ecosystems, thereby injecting a core momentum into the digital urban design framework. Simultaneously, Yang Junyan’s team applies urban vital signs diagnostic technology to the Nansha New Area in Guangzhou, demonstrating the immense potential for precision intervention within large-scale territorial planning. The horizon of urban design is accelerating into volumetric and multi-layered dimensions. Through a comparative study of international low-altitude airspace planning, Zhang Boya, Liang Sisi, Zhuang Weimin, and Zhang Wei provide a global perspective for this emerging frontier. In the subterranean realm, Yuan Sinan’s team utilizes virtual reality (VR) wayfinding experiments to reveal the transformative value of VR in spatio-cognitive understanding and design optimization. Regarding the granular governance of ground-level space, this issue presents a diverse array of practice-led inquiries: Wang Haofeng’s team utilizes the configurational characteristics of street networks to uncover the identification mechanisms of local areas in Shenzhen. Han Jiangxue’s team adopts Shenzhen’s Huaqiangbei as a lens to showcase the intelligence of data-driven governance within existing urban spatial stock. Xing Teng, through micro-regeneration in Beijing’s Liren Street, illustrates the symbiosis between digital technology and situated humanism at the block scale. Sun Ziying and colleagues explore the experimental application of “light intervention” design methodologies in heritage regeneration through the transformation of ruins on Isola di Dino, Italy. Confronting the challenges of urban resilience, Fu Xiaokang’s team discusses urban waterlogging identification grounded in social sensing, while Lai Yuan’s team draws on New York’s Big-U project to dissect the synergistic logic between resilient infrastructures and flexible governance. Furthermore, this issue pays particular attention to socio-spatial equity: Sheng Qiang’s team analyzes spatial usage in Beijing’s Taipingqiao through a gendered lens, while Xu Chenfeng’s team quantifies gendered differences in campus landscape perception using eye-tracking experiments.
       The future of the digital city requires both cutting-edge technological breakthroughs and a nuanced phenomenological warmth. We anticipate that these research contributions will spark broader transdisciplinary dialogues, propelling urban design from the mere iteration of tools toward a fundamental reconstruction of values. We extend our profound gratitude to all contributors and invite our readers to explore this field of emerging possibilities together. [Detail] ...