Visual exposure to buildings in Switzerland: spatial patterns and changes over six decades.

The visual presence of buildings in rural landscapes is a key yet often overlooked dimension of spatial development. This study presents a comprehensive visual exposure assessment of rural buildings, defined here as buildings located outside building zones, across Switzerland from 1960 to 2024, using binary and cumulative viewshed analyses. By integrating historical and contemporary building footprint datasets with digital height models and forest cover data, we quantify how visibility to buildings has evolved across five biogeographical regions. Results reveal a steady increase in visual exposure, primarily driven by construction in non-building zones, despite regulatory efforts to contain urban sprawl. The Plateau region exhibits the highest cumulative visibility due to its dense settlement and open terrain, while the Alpine regions maintain significant areas with minimal visual intrusion. Temporal patterns show that the most significant increases in visibility occurred between 1960 and 1980, aligning with broader trends of urban sprawl. The findings underscore the importance of incorporating visual exposure metrics into spatial planning and landscape monitoring frameworks. This study contributes a visibility-based perspective to the assessment of rural development and offers a valuable tool for evaluating the visual quality of changing landscapes.