Traditional Visibility Graph Analysis (VGA) has long been a cornerstone of space syntax, yet its reliance on binary co-visibility limits its ability to fully capture how people see, understand and move through space. This talk introduces Second-Generation VGA — a major step forward that replaces simple binary visibility with area-weighted isovist overlap. Using custom-built software (Blink), we explore two new measures: symmetric overlap, which treats visibility between locations equally, and asymmetric overlap, which incorporates direction and transitional perception into the model. These refinements enable VGA to represent spatial experience more realistically, capturing subtle visual cues that influence movement.
Our case study in Barnsbury, London, compares these weighted measures against conventional VGA and observed pedestrian movement, and the results are striking: both symmetric and asymmetric overlaps produce significantly stronger correlations with real-world activity, with asymmetric overlap providing the most accurate predictions to date. By integrating perceptual weighting into VGA, this approach bridges the gap between spatial configuration and human behaviour; it not only boosts predictive power but also opens new opportunities for modelling urban movement with greater realism and precision.
This work was first presented at SSS14 and has since been extended in a journal article published in Archnet-IJAR: International Journal of Architectural Research, and the seminar will also introduce OmniVista 25, an online, ultra-fast, web-based VGA analysis tool developed at Syntax North.
[This webinar is free to attend, but please register in advance.]