The spatial arrangement of the main stops considered by the previous authors, reveals a significantly different distribution of sites in the territory. In our analysis, we have omitted some points that were considered very close to others, such as the case of Puente de Meyjaboy with Marzán or Iría Flavia with Padrón (Fig. 2).
Fig. 2 Positions for each of the mansions in the Antonine Itinerary according to the various published studies. The position of each of the mansions can be found in different colors according to the authors consulted. Hence, the positions differ and there is no agreement in the study of the Road XI from Tude in Pontevedra province to Lucus Augusti in Lugo province Full size image
If we compare these results with the starting MADO analysis, we can notice how the optimal paths connecting the territory only match with specific segments of the proposed stops. This is due to two issues: The first one is the slope of the terrain, which rises from barely 50 m at Tui to 650 m at Lugo. It is essential to consider that only 24% of the terrain is flat, with less than a 4º slope, 42% with a 4–12º slope, 21% with a 12–20º slope, and 14% of the territory with slopes higher than 20º. This general trend in the Galician territory, the heart of the area under study, makes mobility difficult, with only a few natural paths. Additionally, this implies that the MADO analysis shows indirectly the three main corridors to connect the three cities that controls the territory: Bracara Augusta, Brigantium, and Luco Augusti (as noted above) (Fig. 3). This means that the MADO model used here, provides us with the main corridors, because the geography of the terrain is quite variable in both topography and slope. The natural passes are what they are and, therefore, the chosen communication routes must be within these areas.
Fig. 3 Optimal routes on Gallaecia territory (Pontevedra, Coruña, Lugo), using MADO tool. This figure represents indirectly the three main corridors to connect the three cities that controls the territory like Tude (Tui), Lucus Augusti (Lugo) and Brigantium (A Coruña) Full size image
The second consideration is that, clearly, the topography has not been considered in the interpretations of the possible stops, as there are possibilities that are far from the main corridors. To address this, we have conducted a second analysis of them, together with cost routes. This way, the aim is connecting each potential stop to the next possibility (Fig. 4).
Fig.4 Least- Cost Path routes proposed for the studied territory in Pontevedra, Coruña and Lugo. The aim of this results is is connecting each potential stop to the next possibility taking into account the MADO results and the topography distances Full size image
In this map, the optimal paths are nearly unique, at the beginning from Tude to Aquis Celenis, with only one of the possible movements considered in one case. This implies that the territory is so challenging to traverse that those options are limited. In the case of the West–East route to Luco Augusti, the problem is more significant, as there are more possibilities, along with an increased distance.
The process of proposing an optimal route has relied on topographical considerations to define the corridors. In Fig. 5, a detailed view of the beginning of the road between Tude and Burbida is shown.
Fig. 5 Detailed view from Tude to Burbida with Least-Cost Path. This figure represents a detailed example of the connectivity between the first two mansions fro Tude to Burbida (Pontevedra province) in relation with the 4 positions that other researchers have proposed Full size image
In this case, by visualizing the terrain slopes and other features such as rivers, it becomes evident that mobility through the territory can only be achieved through the two corridors outlined as optimal ones. This implies that, in this particular case study, the optimal paths resemble closely the surveyor's choice, when selecting routes, because there are no other viable options. In this regard, calculating not just the antropic distance, without considering the slope but the accumulated cost with topography, means that not all paths adhere to the distance provided by the itineraries.
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