Spatial linear network Voronoi analysis to quantify accessibility of police stations in South Africa

Abstract

This study quantifies the overlap between existing police precinct boundaries and theoretically optimal boundaries derived from Voronoi diagrams based on Euclidean and network distances. Accessibility refers to how easily an individual can reach a police station, with closer points being more accessible. There is a need to understand whether current police precinct boundaries effectively facilitate accessibility to police stations, which has an impact on accurate reporting and police response. A novel network Voronoi algorithm, together with spatial similarity measures, is used to determine regions at risk for access to police stations. For police precincts with low similarity values when compared to the proposed network Voronoi areas, which is validated by analysing the proportional change in the number of crimes reported within the different boundaries. The decrease observed suggests that a significant portion of crimes are being reported to other, nearer, and more accessible police stations. By quantifying these relationships, this research evaluates the effectiveness of current precinct boundaries and their potential influence on the accuracy of crime reporting and true police accessibility.