Origin-destination (OD) cost matrix

A network is a set of interconnected lines that can represent features such as rivers, roads, waterlines, telecommunication lines etc. In ArcGIS, transportation networks can be modelled by using a network dataset comprising of a road network. This type of analysis models movement of people or goods that are transported along the road network. The OD cost matrix solver, an application in ArcGIS ® [33], finds and measures the least-cost paths along the road network from multiple origins to multiple destinations. This was used to generate a least-cost path, which refers to the best path that one can travel. The output is a matrix of the shortest travel times and distances to all destinations from all origins. The residential locations of participants diagnosed with heart problems were put into the network analysis model as origins and the location of health facilities were destinations.

The OD cost matrix solver was based on a few assumptions. The first is that participants will choose the shortest path to the nearest health facility [34]. The second is that the shortest travel time to a health facility is the shortest path to health care [34]. Third, the network analysis model assumed that survey participants experienced the same travel conditions therefore variation in factors that influence travel time such as day of the week, time of day, traffic patterns and weather are held constant [35]. Lastly, although a hierarchal speed limit classification system was used in the analysis, travel distances could not account for the variability in road surface types which could affect speed [35].