A while ago I worked on a project that analysed the road networks in a number of towns and cities in England. Initially, we used the Ordnance Survey’s Integrated Transport Network (ITN). The process to extract an ITN network for a specific town was as follows:
- Using Digimap, extract the ITN network for a bounding box around the specific town.
- Extract the boundary polygon for the town and then trim the network to that polygon
- Tidy the road network – removing nodes (junctions) without edges (links), edges without a node at either end and disconnected islands. Fortunately, these tasks can be carried out within QGIS.
As you can imagine, this process is time-consuming and it limited the number of towns that we could analyse. Continue reading “Extracting town road networks from OpenStreetMap”