A Computational Method for Measuring Landmark Visibility Change Caused by Urban Infill Development

This study proposes a method to quantify how infill insertion affects the visibility of landmarks. Visibility impacts are rarely assessed because existing visibility methods provide limited support for comparing conditions before and after new volumes are introduced into established urban fabric. Building on isovist field logic, we reformulate visibility as a building-centered field defined as the set of observation points in public space from which a specific landmark can be seen. Visibility change is computed by sampling unobstructed lines of sight between observation points and sampled points on the landmark’s envelope, accounting for occlusion by surrounding volumes. Observation points are weighted by use, prioritizing pedestrian areas over vehicle space, to produce a visibility-change indicator and heatmaps. The proposed visibility-change indicator has the potential to support urban-design decisions by comparing alternative infill scenarios and identifying where and to what extent landmark visibility is affected.