Adding Visibility to Visibility Graphs: Weighting Visibility Analysis with Attenuation Coefficients

TL;DR

This paper introduces a novel method to weight visibility graphs with attenuation coefficients to account for weather conditions like rain, fog, and snow, enhancing the accuracy of visibility analysis in urban environments.

Contribution

It presents a new approach to incorporate weather-induced visibility attenuation into visibility graphs, improving the realism of spatial connectivity assessments.

Findings

Visibility decreases significantly under adverse weather conditions.

Weighted visibility graphs better represent real-world line-of-sight limitations.

The method demonstrates notable variance from traditional straight-line visibility assumptions.

Abstract

Evaluating the built environment based on visibility has been long used as a tool for human-centric design. The origins of isovists and visibility graphs are within interior spaces, while more recently, these evaluation techniques have been applied in the urban context. One of the key differentiators of an outside environment is the weather, which has largely been ignored in the design computation and space-syntax research areas. While a visibility graph is a straightforward metric for determining connectivity between regions of space through a line of sight calculation, this approach largely ignores the actual visibility of one point to another. This paper introduces a new method for weighting a visibility graph based on weather conditions (i.e. rain, fog, snow). These new factors are integrated into visibility graphs and applied to sample environments to demonstrate the variance between assuming a straight line of sight and reduced visibility.