## 2 Materials and Methods  
### Area Mapping Method Using UAVs Flying on Regular Polygons  
A 2D surface is intended to be covered with points equidistantly distributed using regular polygons. The surface can be covered in this way with points grouped into equilateral triangles or squares (Figure 1).  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Applications** & **Reference** & **Objective** & **Network** \\ \hline Meteorology & [27] & Obtain information about near-surface thermodynamic fields & No \\  & [28] & Measure the temperature and relative humidity & No \\  & [29] & Measure the wind speed and wind direction & No \\ Rescue mission & [37] & UAVs perform the building and exploration of a honeycomb map & Yes \\ Communications & [30] & Investigate the UAV-based air-to-ground-radio vortex & Yes \\  & [31] & Routing in a vehicular ad hoc network (VANET) & Yes \\ Transportation & [33] & Exchange data packets during a contact such that the data & Yes \\  & [34] & Delivery delay decreases and the delivery ratio increases & \\  & [34] & Study the potential of delivery and passenger drones & No \\ Agriculture & [35] & Coordinate drone movements in order to perform adequate count & Yes \\  & & measures against parasite attacks & \\ Cartography/photogrammetry & [36] & Aerial image acquisition and processing & No \\ \hline \hline \end{tabular}
\end{table}
Table 1: UAV applications.  
A new method for UAV network analysis and evaluation based on experimental preliminary flight tests is proposed, as shown in the flowchart from Figure 2. The experimental preliminary flight test of the UAV performed under different environmental conditions allows estimation of the UAV performance under real conditions. The results are used as input parameters of simulation for different DTN algorithms.  
An environment map is essential for both UAV flight control and in simultaneous localization and mission tasks. There are three map types, as was mentioned in [41], metric, topological, and hybrid maps. A metric map is represented as a grid, geometric, or feature map [37]. Topological maps are represented by graphs comprised of nodes and edges, where nodes represent places, and edges represent the path between nodes [37; 41]. A hybrid map consists of small metric map places in nodes, connected by edges that are the paths between metric maps [37]. In this work, a topological type map was proposed.  
To cover a surface, a hexagonal cell comprising three operational equilateral triangles is considered (Figure 3). Each operational cell is covered by a UAV. All the UAVs that operate in the proposed network cells have a specific mission profile. In the middle of each cell, a battery charging/changing station is placed. Thus, in a hexagonal cell, three UAVs share the same battery charging/swapping dock.  
Figure 1: Polygons map: **(a)** Covering a 2D surface with equilateral triangles; **(b)** Covering a 2D surface with squares.  
Figure 2: Novel method for preliminary UAV network analysis.  
Each flight mission profile consists of several phases or steps. A general flight mission profile of the UAV consists of the following main steps: engine start, take-off, climb to the cruise altitude, cruise, hovering and data exchange, descent, landing, and engine shutdown. The next step consists of charging or swapping the UAV battery followed by a new flight mission. The triangular-shaped flight mission profile of the UAV contains three cruise segments (Figure 4). Each cruise segment is followed by hovering and data exchange steps.