David Pettegrew and I continue to make revisions to our article on the fortification around the sites of Vayia and Lychnari bay. One of the reviewers suggested that instead of simply describing the views from the fortified heights of Ano Vayia and Lychnari, we could do a viewshed analysis. Viewshed analysis describes any number of methods used to determine the intervisibility of points on a map. Generally they are performed using geographic information system software (GIS) and are based on Digital Elevation Models (DEM or more properly a DTM, Digital Terrain Models). My viewsheds are pretty basic. They derive from a DEM based on the 1:5000 maps of the Eastern Corinthia. I then use ESRI's spatial analyst to produce very simple viewsheds based on the 6 known sites along the eastern Corinthian coast from Mt. Oneion and Stanotopi to Ano Vayia.
The circles are the sites and the blue line represents the route south from the town of Kenchreai, which is not labeled on this map but would have been immediately north of Mt. Oneion and Stanotopi, which are the three sites lined up east to west across the rocky spine that projects into the Mediterranean as a small peninsula. The site from which the viewshed derives is labeled in each of the illustration below. The dark black line is the Saronic coast line.
I am not sure that these images tell me anything more than what we already could say based on simple observations from the various points in the countryside. Here is the argument that we offer in our paper:
"The towers and buildings at Vayia, however, do make sense as military installations guarding key travel and transportation corridors through the region. The Lychnari tower sits on the far western side of the Lychnari hill and seems to be positioned to overlook the bay and the northern coast of the Corinthia, while the Ano Vayia tower overlooked the pass from Frangolimano as well as the Vayia River valley. Indeed, both towers were clearly intervisible and well-placed to work together to monitor movement in the area of Lychnari and Vayia. The tower at Ano Vayia overlooked movement through the pass leading south to Frangolimano, but the height of the coastal ridge of Kaki Rachi compromised its view of the northern coast of the Corinthia and the Saronic islands. The tower on Lychnari, in contrast, could not see clearly into the pass but had a good view of the northern coast of the Corinthia including most of the Saronic Gulf and islands. Together these two fortifications could have worked to guard against an invading force traveling either westward through the pass or by sea along the coast. To the north Acrocorinth is visible in the distance as are the occupied heights of Vigla,near the village of Almyri, and the fortifications at Stanotopi, Oneion, and even Kenchreai. The sites at Acrocorinth, Oneion, Vigla, and Stanotopi lacked a clear view of the bays located along the southern coast of the Corinthia. In fact, without the towers situated near Lychnari bay, it would have been possible for a substantial force to land at Frangolimano and move east and north toward the Isthmus hidden by the coastal heights and completely out of the view of Corinthian positions immediately south of Oneion or on the Isthmus. Guards stationed at Lychnari or Ano Vayia ensured that this inland route remained in communication with forces positioned closer to the Isthmus and could provide an early warning for the heartland of the Corinthian chora to any danger threatening these more peripheral communities.
The kind of network and communication proposed here is well-documented in other regions of the Greek mainland. J. Ober and M. Munn have shown how rural towers in Attica belonged to networks of routes, towers, and fortified sites that functioned together for local defense in the Late Classical world. Recently, J. Marchand and Y. Lolos scholars have demonstrated the close link between towers and roads and argued that states situated towers so as to control traffic through the countryside. As we have already noted, Lolos documented a tower at Tsakouthi in the Sikyonia with similar size and construction technique to the round tower on the height of Lychnari; he argued that it overlooked a significant roadway linking the Sikyonian plain to the region around Stymphalos. Wiseman, Smith, and others have likewise associated a network of towers with the road network that passes from the southern Megarid into the Corinthia via either the Kaki Skala or over various passes through Mt. Geraneia. In these contexts, rural towers functioned mainly as signal stations across the countryside that connected military forces, rural communities, and polis centers separated by long distances and rocky terrain. The towers at Ano Vayia and Lynchnari would have functioned in a similar way, although the rectangular building at Ano Vayia and the rubble fortification on the Vayia peninsula also suggest brief or occasional occupations by small garrisons perhaps positioned to protect the area against small-scale raiders. The impressive views afforded the Lychnari and Ano Vayia tower must have extended the influence of any force stationed in the rubble fortification on the Vayia peninsula.
In sum, the position of the Lychnari and Ano Vayia towers in the landscape, along with the evidence of the artifact assemblage, encourages us to understand the principal function of these structures as militaristic. The ease with which a force could pass north from the Bay at Lychnari or even Frangolimano into the rolling country south of Oneion made the fortification of this stretch of coastline crucial to any Corinthian strategy designed to protect territory peripheral to city’s central chora on the Isthmus. The fortification of Vayia and Lychnari find parallels in Corinthian (and allies’) efforts to guard or block vulnerable passes in the mountainous regions of Corinth. The large and complex fortified site of Ayia Paraskevi near the modern village of Sophiko, for example, overlooks a fertile plain and several major lines of communication and travel through the southeastern Corinthia.While this site could represent a fortified outpost for a village of the Corinthian interior, its position also suggests a military function not dissimilar to the “border forts” along the Attic-Boeotian frontier. Similarly, the impressive array of rubble fortifications along the ridge of Oneion must represent efforts to control passage across the eastern ridge of the mountain and indicate a clear strategic initiative to control passage through the rugged interior of the Corinthia—even if those walls should represent a temporary occupation by a foreign power."
The total viewshed of these six sites, however, is interesting:
Basically, these six sites combine to blanked the Eastern Corinthia with the exception of the small inlet at Katakali and its beach (it's the largest bay that is not red near the center of this map. I would be reasonable to look at the height to the west of this inlet, perhaps, for a tower. A tower built on that hill would not only be visible to other sites in the area, but also be poised to watch over this embayment. Of course, this tower might not serve too obvious a strategic function in that other towers would cover the most visible routes out of the vicinity of the embayment. The lack over coverage over Lychnari bay is an artifact of the DEM and my analysis. The bay is clearly visible from the tower at Lychnari.