The use of hexagon tessellation for virtual network analysis of evacuation distance

摘要

Earthquakes and tsunami affecting Central Sulawesi, Indonesia have been recorded since 1927. The last tsunami in 2018 washed the shoreline for not more than five minutes. The objective of this study is to determine evacuation distance by using three different methods of network analysis: the current method (existing road network model), the proposed combined virtual network model, and the real-world evacuation route which is used as the standard parameter. This research includes four steps which are: building the three types of networks, determining the Origin and Destination (O-D) points, running the solver, and finally comparing the distances determined by each method. All of the network builds and analyses use the closest facility solver within the ArcGIS network analysis tools. With different characteristics, this study, carried out in Palu, Indonesia, shows that the evacuation distance method using a combined virtual network model is more closely resembles real-world evacuation distance; only one out of 20 routes which were analysed did not show the maximum performance compared to the real-world network model. On the other hand, the existing road network model shows two routes deviating from the route determined by the combined network model, meaning a weak performance of the method in measuring the evacuation distance.