# Outside Dynamic Evacuation Routes to Escape a Wildfire: A Prototype App for Forest Firefighters
## 3 Materials and Methods
### Evacuation Routes Algorithm
The results are presented using the Google Maps platform. ### Basic Scenario: Without Terrain Elevation

The results of the route creation algorithm are evaluated through a topographic study of the terrain. The elevations of each point in the area are obtained with Google Maps, and the type of vegetation is analyzed using each Google Tile; this allows identifying the amount of vegetation on the road. Furthermore, the distance from the start point to an endpoint (evacuation point) is considered. The characteristics for this scenario are:

* There is less density of vegetation on this road. * It does not have high elevations. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Coverage** & **Lf (dB)** & **Lw (dB)** & **Litu (dB)** \\ \hline
70 & 76.94795782 & 97.68511795 & 103.381307 \\
80 & 78.10779676 & 100.5387921 & 106.7461051 \\
90 & 79.13084721 & 103.1703914 & 109.8662475 \\
100 & 80.04599702 & 105.6219387 & 112.7871047 \\
110 & 80.87385072 & 107.924054 & 115.541866 \\
120 & 81.62962194 & 110.0998015 & 118.155622 \\
130 & 82.32486407 & 112.1670289 & 120.6478535 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Coverage results of the models evaluated. Figure 4: VSN model used for monitoring (Google Maps). It has a firewall in its path. * There is a distance of 861 m between the starting point and endpoint. Figure 5 and Table 2 show the basic scenario configuration; each scenario (basic, intermediate, and advanced) has a starting point and some evacuation points for the algorithm to find the closest route while the fire spreads. Figure 6a shows the result of the simulation of an evacuation route. It is observed that the route takes the shortest path without deviating its direction. The fire propagation algorithm in the forest is not activated, and the route calculation time is 148.31 s. Figure 6b shows the result of the simulation when there is the presence of fire in the forest; it can be seen how the route reacts by deviating its original direction and identifying another appropriate route that maintains a safe distance from the fire, even if it is not the shortest way to the point of survival. The evacuation route calculation time is approximately 87.73 s with a fire spread time of 39 s.

### Intermediate Scenario: Terrain Elevation

The fire propagation algorithm considers the vegetation density according to the RGB color of the area to be evaluated (Google Tile); if the color is denser (dark green), it is considered a higher density of vegetation. This value influences knowing which areas of the forest are prone to catch fire faster in the event of a fire. A starting point with higher \begin{table}
\begin{tabular}{l c c} \hline \hline
**Metrics** & **Latitude** & **Longitude** \\ \hline Init point of the route & \(-2.1469185167612292\) & \(-79.97643470764162\) \\ \hline Final points & \(-2.148375167612292\) & \(-79.96722470764162\) \\ \(-2.1476485167612292\) & \(-79.96541470764162\) \\ \hline Init point of fire & \(-2.144601088172362\) & \(-79.97226119041441\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Values configured in the basic scenario. Figure 5: Basic Scenario: Without terrain elevation (three save points). Figure 6: Evacuation routes for the basic scenario using Google Maps. density vegetation is considered, as well as a greater distance between the final and initial points. The characteristics of this scenario are:

* There is a higher density of vegetation on this road. * Elevation is up to 70 m.
* There is no firewall in its path. * There is a distance of 935 m between the starting point and endpoint. Table 3 shows the initial configuration of the algorithm. Figure 6(a) shows how the route takes a direct path, with very few deviations on the ground (considering that there is elevation, the path with less slope is taken), and the route calculation time is 100.23 s. Figure 6(b) shows the initial point of the fire; this shows how the route reacts by deviating its original path, moving away from the danger and maintaining a safe distance from the fire.