Viewsphere: A GIS-Based 3D Visibility Analysis for Urban Design Evaluation

Abstract

Previously, GIS-based visibility analysis has been conducted mainly in two dimensions, based on the concept of an isovist in the built environment or the concept of a viewshed in terrain and landscape analysis. The Viewsphere, a GIS approach towards 3D visibility analysis is proposed for measuring visible urban space quantitatively in a way that is different from its predecessors, the isovist and the viewshed. A test case of Singapore's urban space was conducted by evaluating the visibility of three alternative urban design scenarios and their potential impacts on the visual quality of open space. Both directional and nondirectional approaches were applied to the mapping of visibility based on the 2D and 3D indices. The proposition that 3D visibility indices are more effective than 2D indices was verified. The findings show that the 3D indices are sensitive to the changes of z-dimension.

Application of Viewshed and Spatial Aesthetic Analyses to Forest Practices for Mountain Scenery Improvement in the Republic of Korea

“…In general, viewshed analysis of natural environments is used to assess the scenery value by topographic substrate and vegetation through the division of visible and invisible areas. Recently, it has been applied in various fields such as determining the problem related to viewing rights because of shielding by buildings in urban areas and the analysis of visible areas of closed-circuit televisions installed for the prevention of forest fires in mountainous areas [46][47][48][49].…”

Analysis and Simulation of Dynamic Vision in the City

“…These thematic physical appearances 10 An isovist means the space visible from a given vantage point (Benedikt 1979, Batty 2001. A complete 3D isovist includes the entire space that is visible for all possible viewing orientations of the observer (see Fisher-Gewirtzman, Burt, and Tzamir 2003, Yang, Putra, and Li 2007, Lu et al 2019. Dynamic visual research repeatedly occur over time, indicating prevailing environmental elements.…”

The Unequal Impact of Natural Landscape Views on Housing Prices: Applying Visual Perception Model and Quantile Regression to Apartments in Seoul

“…Two major groups of studies on landscape quantification have been performed. One concerned calculating the area of various objects that can be viewed using viewshed analysis [12,17,[38][39][40][41], and the other involved determining a visual perception using the spatial relationship between a specific target object and a viewpoint to determine the psychological effect of the target object on the observer [42][43][44][45][46][47]. The former group involved evaluating the landscape by calculating the planimetric area for each target object, although recent studies have improved the accuracy of the analysis by using more precise three-dimensional data [17,41].…”

“…The latter group of studies quantified the view analysis results using the concept of visual perception. However, the study [42] only evaluated openness among factors affecting property value, and [43] did not analyze irregular topography. Studies [44] and [45] attempted to quantify exact visual perceptions using a solid angle as a viewing unit, but it is necessary to improve the algorithm for applying it to a large area, as these were experimental studies on a small research site.…”