Exploring the Impact of Urban Development on Mountain View Visualization Using a GIS-based Landscape Assessment Model: a Case Study in Lishui, China

Amid China's high-speed urbanization, the lack of urban landscape and homogenization of urban image are becoming increasingly serious, prompting discussion on how to preserve the natural urban landscape. This study extends the existing landscape assessment model to evaluate the urban hillscape of the Lishui urban area of Nanjing over the past 50 years. First, a landscape quality analysis is conducted based on raster images, and a landscape quality map of the study area is drawn. Then, a visibility analysis of the site is conducted, key observation points (KOPs) are screened using a digital surface model, and the visual magnitude of each KOP is quantitatively calculated. Finally, the visual impact scores of the mountains in the site are synthesized. The results show that the model can accurately quantify the visual impact of historical mountain views. The following conclusions are drawn (1) The visual quality of the landscape in the area has improved as the urban area has spreads out. (2) The viewshed and magnitude of the area are trending downward over time. (3) The Chengnan area's visual impact score increased by 25.7%, but that of the Tuanshan and Chengzhong areas decreased by 48% and 26.9%, respectively. This study presents a spatial decision support system that can obtain better landscape assessment results with more accessible open-source data, and can be used for historical landscape evaluation. By comparing the characteristics and trends of urban hillscapes in different historical periods, this study's landscape assessment model can help managers better understand the impact of development on urban intentions and make better decisions.