Another objective we can consider is minimising the travel cost. By changing our objective function in the optimisation model, we get the optimal path in the animation above.
The cheapest trip finishes the tour in 20 days and 23 hours. In the map above, blue lines represent flights and black lines represent bus journeys.
Cheapest trip details
We start this trip at St. Petersburg and finish at Baku. Our most expensive connections are from St. Petersburg to London with an average price of €177, and from Budapest to Baku for €160. We use bus and ferry connections on this trip. Total trip time, in this case, is quite long – almost 21 days.