## 1 Introduction
[PERSON] et al. identified the basic functionality requirements for DTN support comparing the Epidemic Routing and Named Data Networking [25]. They concluded that in the network storage, DTN communications critically depend on the store-carry-forward mechanism. [PERSON] et al. analyzed the effectiveness of the DTN system in a communication network on a railway line [8], showing a 20% reduction in message delivery time depending on the schedule of trains. [PERSON] et al. proposed a routing protocol called Scheduling-Probabilistic Routing Protocol using History of Encounters and Transitivity (PROPHET) to improve the delivery rate and optimize delivery delay with low overhead in DTN for IoT applications [26]. Their performed simulations in the ONE simulator showed that the Scheduling-PROPHET routing protocol achieved a high delivery rate and reduced delivery delay while minimizing resource consumption in transmission. The UAVs with their flexibility are popular and have gained importance within many applications across many domains such as atmospheric sciences [27; 28; 29], communications [26; 30; 31; 32], transportation (delivery) [33; 34], agriculture [35], cartography [36], rescue missions [37], etc. The UAV applications are summarized in Table 1, which shows whether the UAVs are grouped into networks. In the literature, there are very few papers considering networks consisting of regular polygons. In addition, most of the studies do not specify the drone type. [PERSON] et al. proposed a bio-inspired coordination protocol for UAV flying ad-hoc network (FANET) management in the agriculture domain [35]. The proposed system has been simulated in an ad hoc simulator, and a preliminary analysis about the feasibility of the UAV design for the specific purpose has been performed. [PERSON] et al. investigated the UAV-based air-to-ground wireless networks and evaluated the performance of the branch and bound search-based mode selection (BBS-MS) [30]. Vehicular ad hoc networks (VANETs), which are a type of mobile ad hoc network (MANET), play the most important role in an intelligent transport system. Within the VANET, the mobile vehicles can establish three main categories of communications: vehicle to vehicle, vehicle to infrastructure, and infrastructure to infrastructure. A relative recent application of VANET is for a UAV network that can communicate for message relaying with each other via wireless links [31]. The UAV flight path planning problems can be categorized as off-line planning, on-line planning, and cooperative planning [38; 39]. The limited battery energy of UAVs [40] allows them to fly for a relatively short distance. Using UAV networks, a large area can be covered. [PERSON] et al. proposed a space mapping method using a topological map as a collection of hexagons; each hexagon can hold a maximum of one UAV [37]. The simulations in different scenarios show possible applications of this method for indoor rescue missions. [PERSON] et al. proposed heuristic flight path planning (HFPP) that plans a UAV's flight path based on parcel delivery destination as well as data delivery destinations [33]. Their results showed that HFPP delivers up to 33% more data packets compared with Encounter-Based Routing and Epidemic routing protocols. DTN networks are useful for providing communication in environments where frequent transmission discontinuities are present. The main objective of this paper is to ensure communication between isolated areas or in areas with technical damage. In these circumstances, we considered a UAV network with a precise travel and rest period. Thus, the interest would not be on having a multi-copy routing protocol, but on establishing the optimal path for the messages. The results obtained by the proposed TD-UAV Dijkstra algorithm, a single-copy algorithm, and multiple-copies algorithms were compared in the case of buffer-limited capacity. A space mapping method using a topological map as a collection of regular polygons is proposed.