This study discusses applications of Network Voronoi diagrams for spatial analyses. I compared Network Voronoi diagrams with plane Voronoi diagrams. This method does not make network cells on the line of the network, but makes areas using network distance. In this method, a plane Voronoi region is made for every node on a street network. The nodes have the nearest shelter point from them by network distance, and the shelter point holds the area of those nodes and makes one region, a Network Voronoi region. This method can overlay the point data on a plane and a network, and we represent moving by the nearest street. As a case study, I calculate the shortage of shelters' capacity using Network Voronoi diagrams. The study area is central Sapporo city. In this case, a Network Voronoi region represents the area that residents move to near shelters on street. This result shows applications of this method, Network Voronoi diagram for spatial analyses.