With the popularity of intelligent mobile terminals, as well as the improvement in wireless communication technologies, the application of real-time charging navigation for electric vehicles (EVs) has met a booming development in recent years. Accordingly, more and more EV owners tend to make their charging decisions depending on the guidance from navigation systems, which to some extent transforms the EV charging demands into spatially dispatchable resources in the operation of distribution systems. To involve this spatially dispatchable characteristic at the planning stage of distribution systems, and deploy power devices in a cost-effective way, a comprehensive optimization model concerning the joint planning of distributed generators (DGs) and electric vehicle charging stations (EVCSs) is proposed in this paper from the perspective of a social planner. The proposed joint planning model is embedded with the spatial scheduling problem of EV charging demands, and focuses on the optimum of relevant social costs. To relieve the complexity of the optimization model, an exact second-order cone programming (SOCP) relaxation is utilized to transform the proposed model into the type of mixed integer second-order cone programming (MISOCP), which can be efficiently solved in polynomial time. Finally, a practical urban area coupled with the 33-bus distribution system is used as the test system to implement the proposed approach, and the corresponding allocation schemes as well as annualized social costs are minutely presented. The numerical comparison with traditional Voronoi diagram-based planning methods reveals the significant economic benefits achieved through considering real-time charging navigation technologies.