Locating a Late Minoan Settlement near Prina on Crete (C7884)

In Hayden [2005] there is a description of a Late Minoan settlement in the Vrokastro area of Crete.  The site sits just below the western boundary of Hagios Nikolaos Bay.  I have given it the identifier C7884.  The general situation is this:

 The approximate position of C7884 (which I will justify here) is  35.093541° N,  25.699069° E.  Hayden describes it as follows:[1]

"Location

Nearest modern village and distance: Prina, 2.25 km.; 

Distance from sea: 4.8 km.; 

Elev.: 280 m.; 

Toponym: Kato Prina;

Location on Brit. map: 10/64.15; 

Transect: 12: 2:2:805-890 p.; pottery collected by field.

Topography

The site is located on the central plateau of a ridge that extends E-W in the middle of the pass between the villages of Prina and Meseleroi. 

Slopes of the ridge are 10°; the location takes advantage of water sources on both sides of the ridge; a spring to the S at Aghios Georgios, and a well located below the ridge to the NE. Directly S and paralleling the ridge is a ravine that may also have been a seasonal water source."

Analysis

My position for Hagios Georgios was derived from Hayden as follows. She says "The site is located on the central plateau of a ridge that extends E-W in the middle of the pass between the villages of Prina and Meseleroi." There is such a ridge. It stretches from about  35.093340° N,  25.705669° E at the east end to about  35.093864° N,  25.698154° E on the west.  It is visible in the next figure.

Looking WNW from the pass to Meseleroi and in the direction of Prinas.  The ridge which Hayden mentions is in the foreground.  It continues to the W where, near its end, sits the settlement (green paddle)

The chapel of Hagios Georgios (F7970) sits about 310 m south of the west end of this ridge at F7970. It is separated from my proposed location by a shallow valley (elevation drops about 20 m) which is what I take Hayden to mean when she says 'Directly S and paralleling the ridge is a ravine that may also have been a seasonal water source.'  The following figure should make this clear:

The site C7884 is in the center at the green paddle.  The ridge on which it sets is marked by the 'H' paddles at the far upper right and in the center just outside the circle.  The straight line is drawn from the chapel of Hagios Georgios, F7970, to the site center at C7884.  The elevation profile of that line is at the bottom with F7970 on the L and C7884 on the R.  The chapel sits at about 296 m; the settlement site at about 280 m.  Between them the valley dips about 20 m.

Hayden speaks of 'a well located below the ridge to the NE' but I cannot locate it.

The driving distances from the SW edge of Prina to the site ranges between 2.1 and 2.3 km. compared to Hayden's 2.25. 

A driving route from the town of Prinas (L) to the site at the green  paddle on the right.
The suggested routes (left panel) are 2.1, 2.1, and 2.3 km.

The elevation at C7884 is 271 m. vs. Hayden's 280. 

The distance from the marker to the nearest seashore (at 35.129150° N,  25.727914° E) is 4.742 km vs. Hayden's 4.8.   I show this in the next figure.

A circle centered at C7884 (green arc) touches the shore (green paddle labelled 'Shore') at 35.129150° N,  25.727914° E.  The radius of the circle is 4777.5 m.

Hayden requires a slope of 10° for ridge on which the site sites.  From my suggested location the slopes (averaged at 150 m from the marker) are: to N: -7.24; E: 14.1; S: 3.36, and W: -10.08.  In this rolling country a single numerical parameter is not adequate to describe slope at the site.

Slopes at 150 m. from the marker for C7884.  The slopes vary more sharply at north and west; less so to south and most sharply to the east.

These agreements are sufficiently close for me to suggest this particular location. Her language sometimes suggests that the location is further up on the ridge to the E in the direction of Meseleroi. But the elevations there are in the 340 m. range; a substantial increase over her suggested 280 m.

Another source for this area is Pollard [2022] who gives the coordinates 35.09587 N, 25.70013 E for this site. [2] But I cannot convince myself that these coordinates are correct as they fail Hayden's prime criterion that the site should sit somewhere on a ridge that runs through the pass between Prina and Meseleroi.  Pollard's site would be on the northern edge of the Prinas valley and not on a ridge running through the pass.

Pollard's suggested lat/lon position on the upper left.  This position (on strongly sloping ground) is on the next ridge to the north.  It forms the northern boundary of the Prinas plain and the northern edge of the pass to Meseleroi.  My suggested position is at C7884 at center left.

Determining an accurate location of the ruined Venetian chapel of Hagios Ioannis would settle the matter since we are told (10) 'On the SE edge of the site is a ruined 15th c.? Venetian church of Aghios Ioannis, marked on the British 1:50,000 map.' I have examined the 'British 1:50,000 map' and while it shows the  name  of 'Ay Ioannis' it does not provide an icon to mark its position.

The ruined Venetian chapel of Hagios Ioannis.
Hayden  [2005] 'Photographic Tour of Vrokastro'.

British army 1:50,000 map of the Prina area.  Hayden's suggested position for C7884 is (10 x 64.15) which I have marked on the map with an arrow.  We see that the name 'Ay Ioannis' is given but without a marker or icon to indicate its position.

I have identified a pile of stone at F7970 and I suppose that this might be the chapel but this is sheerest guesswork.  The only guide is that the chapel should be to the SE of the site.

So we conclude with this:

Final Position of 

C7884 : Prina Hagios Georgios : 35.093541° N, 25.699069° E
C7884 (Pollard) : 35.09587 N, 25.70013 E
F7970 :  Hagios Georgios Chapel : 35.090786° N          25.698758° E
F7971 : Ruined chapel of Ay. Ioannis : 35.09244° N          25.699953° E  Maybe.
F4402 : Town of Prina : 35.095003° N          25.68646° E
F4437 : Town of Meseleroi : 35.0836° N          25.71219° E

In the Mycenaean Atlas (red arrow points to assumed position for C7884) it looks like this:

The Mycenaean Atlas is your preferred gazetteer for the Bronze Age ... and all of Antiquity as well.

Footnotes

[1]  Hayden [2005] Site Catalog, pg. 9, 'Aghios Georgios 2: AG2'.

[2]  The Appendices volume of that dissertation; pg. 54, '320. Prina Agios Giorgios'. 

[3]  Royal Engineers [1943:20] at or near coordinates 10.0, 64.15

Bibliography

Hayden (ed.) [2005] : Hayden, Barbara J., 'Site Catalogue', Supplemental Material from Reports on the Vrokastro Area, Eastern Crete, Vol. 3: The Vrokastro Regional Survey Project: Sites and Pottery. Philadelphia, Pennsylvania: University of Pennsylvania Museum of Archaeology and Anthropology. 2005.  Online here.

Pollard [2022]  : Pollard, Dominic. Between the Mountains and the Sea: Landscapes of Settlement, Subsistence and Funerary Practice in Later Bronze Age and Iron Age Crete: Appendices, Thesis submitted for the degree of Doctor of Philosophy, Institute of Archaeology University College London (UCL).  June, 2022.  Online here.

Royal Engineers [1943:20] : Sheet 20 of 1:50,000 Crete / reproduced by 512 Field. Survey Company, Great Britain. Army. Royal Engineers. Field Survey Company, 512th. MAP G6812.C7 s50, [Cairo?] : Middle East Drawing and Reproduction, 1943-1945. Online here.

Trachia in the Argolid

The 'settlement' of Tracheia dominated the Tracheia valley in the SE Argolid.

The Trachia Valley is the region of the box in the center.

 

The route between Epidauros and Troizen led through the Trachia Valley and then skirting the mountains to the coast just S of the Methana peninsula and then on to Troizen.

 There were two towers protecting the entrance to the valley from the S. The first is the Mnema tou Andreiomenou.[1] 

A second, unnamed, building (presumably a small fort with tower) stood about 800 m to its north on a low hill. Perhaps the hill at 37.544871° N, 23.140036° E is intended.[2] 

The only other structure that may be identified is a small sanctuary in the neighborhood (In der Nähe) of the second tower, perhaps near 37.544343° N, 23.143016° E.[3]

Remains of the 'small sanctuary' [3a]

It is not now possible to say of what the settlement of Tracheia consisted. From Faraklas (through Blomley) we learn of a 'fort' or 'fortified settlement' lying on a low hill somewhere to the SW of modern Tracheia.[4] The settlement may have been of some significance because of the presence of the towers at the entry of the valley and, also, the presence of a major fortification at Bedeni Kiapha (C1081) on the valley's east side.[5]

Some confusion attends the location of the settlement.  Blomley says that the settlement of Tracheia is situated on " ... a low hill SW of Tracheia."[6]  On the S or SE sides of that hill Faraklas found ' ...  ' ... traces of a wall on the S and SE of the hill.'

Simpson and Dickenson say "A LH site was reported near the village of Trachia, on the route between the Asklepieion at Epidauros and Troizen."[7]

Anne Foley says "This site is situated in S central Epidauria about 500 m NW of modern Tracheia."  This would put it in the precise opposite direction from Blomley.

I suspect that the settlement of this little valley stretched to the S and W of the current modern town and back towards the 'small sanctuary' mentioned by Tausend.  I show the final suggested disposition for these various  points of interest in the next map:

And this final map shows how it all fits together:

Upper map superimposed onto a Google Earth image.

Footnotes

[1] For the Mnema tou Andreiomenou see Tausend [2006] 154.  Blomley [2022] 253. '77. TOU ANTREIOMENOU TO MNEMA 1 ... '.

[2] For this second tower: Tausend [2006] 154. ' ... befinden sich auf einem flachen Hügel die Reste eines zweiten Baues ... '

[3] Unwin [2020] npn.  " [footnote] 41 A klidophoros is attested at Side (I.Side 17), while kleidophoroi are also among a delegation sent from Laodikeia-on-the-Lykos to Klaros in the second century CE (Ferrary [2014], no. 40). The variant klakophoros is found at Apollonia in Illyria (I.Apollonia 16) and at Messene (IG V 1.1447); see the discussion of Quantin (2004), p. 596–600. A hero called Klaikophoros is attested at Epidauros in the third century BCE (IG IV² 1.297)."

[3a] Tausend [2006] Abb. 212. "212 Heiligtum von Philanorion".

[4] Blomley [2022] 293, '158. TRACHEIA (Τραχειά)'.

[5] For the Bedeni Kiapha fortress see Blomley [2022] Fig. 6.42, and 184, '16. BENTENI KIAPHA (Μπεντένι Κιάφα, Μπάφι)'.

[6] Blomley [2022] 293.

[7] Simpson and Dickenson [1979] 54, 'A 31 Trachia'.

Bibliography

Blomley [2022] : Blomley, Anna Magdalena. A Landscape of Conflict? Rural Fortifications in the Argolid (400-146 BC), Archaeopress Publishing Ltd., Oxford. ISBN: 978-1-78969-971-5 (e-Pdf). 2022. A precis and first 20 pages are here.

Faraklas [1972] : Faraklas, N., Ancient Greek Cities, xii: ’Επiδαυρος. Athens. 1972.

Simpson and Dickenson [1979] : Simpson, Richard Hope and O.T.P.K. Dickinson, Gazetteer of Aegean Civilisation in the Bronze Age, Vol. I: The Mainland and Islands, Göteborg, Paul Astroms Förlag, 1979.

Tausend [2006] : Tausend, Klaus, Verkehrswege der Argolis: Rekonstruktion und historische Bedeutung, Geographica Historica (Gh), Franz Steiner Verlag, 2006, ISBN-13: 978-3515089432.

Unwin [2020] : Unwin, Naomi Carless. 'Basket-Bearers and Gold-Wearers: Epigraphic Insights into the Material Dimensions of Processional Roles in the Greek East', Kernos (33) 33-125. 2020. Online here.

The geography of Müsgebi in Caria

[Labels in the form of Fnnnn or Cnnnn refer to sites in the Mycenaean Atlas Project.]

Müsgebi, on Turkey's Bodrum Peninsula, is one of the several sites testifying to the supercession of Minoan settlers by Greek-speakers, Mycenaeans, during the Late Bronze Age.[1]  M. appears to have consisted of a settlement site and a large cemetery; the geography has always seemed a bit obscure to me and this post is an attempt to clarify what I have been able to find out.  Figure 1 shows the general situation.

Fig. 1. The Bodrum Peninsula with locations of Bodrum/Halikarnassos, 
Müsgebi/Ortakent, and the island of Kos shown. 

The valley of Müskebi lies about 6.5 km. to the west of ancient Halicarnassus (measuring from the Mausoleum at F2121).  By ferry it is about 2 hrs. from Kos.  The valley itself is about 7.8 km. from N to S.  It ends with a range of hills on the N through which pass roads to Yalikavak on the N coast.  As early as the Bronze age the valley was the location of a Greek settlement that came to be known in the Classical period as Episkopi (C7880).  In modern times the two towns of Ortakent and Müskebi have grown to the point where they have merged; the conglomeration now bears the name of Ortakent.  

In the early 1960's Dr. George Bass, the well-known underwater archaeologist, was exploring this region of the Turkish coast when local informants showed him artifacts (primarily pottery) and told him of graves in the area.[2]  He was able to locate a few of these graves (chamber tombs) which were then intensively investigated by Boysal from 1963 on. [3]   At least 50 chamber tombs were ultimately identified and some excavated.  The haul of pottery was vast.

In 1963 Emily Vermeule[4] and a small team were sponsored in an effort to locate 'the Greek citadel' in the area.  In this she did not succeed but she was able to establish the ancient Greek nature of the area around this coast and establish that the richest source of artifacts was the wells that the inhabitants were enlarging and deepening.  And she relocated Bass's chamber tomb cemetery in an area about 4 km to the N of the coastline and placed in an area rich in white ceramic-grade clay; now a quarry.[5]

Where is the cemetery?

The cemetery is described like this in our sources:

a) Bass [1963] 353 : " ... a low hill about one and a half kilometers from Müskebi. The face of the hill had been cut away by camel drivers who had been seeking white clay for making mortar."

b) Mee [1978] 137: "The 48 chamber tombs were cut into the east and west slopes of a valley 1 km. to the north of Müsgebi ... "

c) E. Vermeule's sketch map marks it unambiguously as 'chamber tombs' and 'Mycenaean'.  She places it directly to the north of 'Müskebi'.  Additionally the photo accompanying her article clearly shows the ridge which shelters the cemetery.   I reproduce the photo here.

Fig. 2.  The Muskebi valley from the sea.  The photo was taken from approximately 37.019823° N, 27.344607° E on an azimuth of approximately 355°
Post-processed by rhc.

  

The caption reads:  "The beach and orchards of Müskebi (formerly Episkopi) viewed from out at sea. The Early Bronze Age settlement lies just inland in the center of the picture, and the Mycenaean cemetery is far up the valley on the right."   This photo is reproduced in Google Earth as Figure 3.

  

 

Fig. 3.  Reproduction in Google Earth of Vermeule's photograph. Here the actual quarry can be seen as the white patch at the very tip of the red arrow.

These indications are consistent with each other and, as a result, there can be no doubt that the quarry/chamber tomb cemetery is at C1495 (37.06842° N, 27.33957° E)

A close-up picture of this quarry from Google Street View

Fig. 4. The ridge and quarry are right behind the sign and the tree. The entrance
to the quarry, about 450 m. distant, is to the right.   The word 'beton' means 'concrete'. 
The picture was taken from 37.064532° N, 27.337401° E

Here is the scene of the quarry as seen in Google Earth.  The location from which the photo in Figure 4 was taken is shown here at bottom center as 'Photo Location'.

Fig. 5.  The quarry in which the Mycenaean Chamber Tomb cemetery of Müskebi was found (C1495).

Location of the Greek Settlement

Fig. 6.  The site of the settlement of Episkopi, Caria.  The site is across the road and to the left (E) of the housing complex in the middle distance.  Note the modern (?) tomb (F7926) on the lower left.  The lighter land-mass on the horizon is Kos. The darker land mass in from of it is part of the Bodrum Peninsula.
Used with kind permission of Eberhard Zangger and Luwian Studies.

The essentially Greek nature of this area and the extensive nature of the settlement was convincingly established by Vermeule.  Many of the pottery finds that she was shown or which her team discovered came from the inhabitants' digging of wells along the coast or close to it.  This is evident from her map:

Fig. 7.  The area of most intensive  pottery discoveries is in the lower left of
Vermeule's sketch map.

Luwian Studies gives the site of the settlement in two ways.  Zangger et al. [2022] 106 gives the site as "350 m south of the old windmills overlooking the old village center of Ortakent."[6]  The Luwian Studies website gives a slightly different location: 37.041583° N, 27.353133° E [7]

These two alternatives are shown in Figure 8.  

Fig. 8.  Upper portion of the Müskebi plain.  

The windmills called out in Zangger et al. [2022] are at the top at F7929.  The tomb clearly visible on the lower left of Fig. 6 is at F7926.  The location 350 m. to S of the windmills is the blue paddle marker at C7880.  The green paddle marks the lat/lon pair called out in Luwian Studies, no. 121.  The Mycenaean Atlas Project currently has adopted the C7880 position for the settlement at Müskebi.  Because of the well-watered nature of this landscape we probably can assume that the Greek settlement spread out over this entire plain. 

Vermeule marked out a larger and different area closer to the mouths of the streams on the S (here shown in blue and a tributary in green).  Figure 9 shows Vermeule's emphasis in context of the above.

Fig. 9.  Southern Müskebi plain.

One final consideration.  Zangger suggests that the river has moved the coastline about two and a half km. southward since the Bronze Age. [9]  That would mean that at the time Müsgebi was inhabited in LH I and LH II the coastline would have looked more like this:

Fig. 10.  During the BA the site of Müskebi may have been on the water's edge.

Here I have tried to indicate what it would look like if we move the sea coast two and a half km. to the north of its current position.  Some of what are currently hills would have been islands and it appears that Müskebi (C7880) would have been on, or very near, to the water's edge.  In other words, there is every possibility that the Mycenaean site of Müskebi would have been a seaport and some of the Mycenaean center of Vermeule would have been underwater.

Footnotes

[1] Plausible scenarios sketched out in Mellink [1983] 139 et passim : " Tombs of Minoan settlers have not yet been found on the Anatolian west coast. Mycenaean tombs begin to be known from Late Helladic IIIA 1-2 on (tomb group from Ephesos, chamber tombs at Müsgebi west of Halikarnassos), not much before 1400.  Aegean archaeologists infer from these data that Achaians from ca. 1450 on were taking over Minoan coastal sites in the Aegean and in West Anatolia (principally in Caria)."

[2] Bass[1963] 353 : "Later I was able to visit Müskebi, accompanied by Haluk Elbe, Director of Antiquities in Bodrum and archaeological commissioner for our underwater excavation, and Machteld Mellink. Haluk Bey explained our mission to a group of townspeople, and soon several more vases were produced from houses in the village. Afterwards we were led along a track, by Bekir Aras, to a low hill about one and a half kilometers from Müskebi. The face of the hill had been cut away by camel drivers who had been seeking white clay for making mortar. The scarp here revealed at least six chamber tombs, quite close together, ... " 

Mellink [1963] 180. "BODRUM-MÜSGEBI.  In 1962, George F. Bass of the University Museum, in charge of underwater explorations off the Carian coast, noticed that villagers in Müsgebi, about 5 miles west of Bodrum, had accidentally exposed some Mycenaean chamber tombs.  These tombs were originally cut into the soft limestone slopes of a hill which is now being used as a source of white earth for the making of mortar.  The site is about an hour from the sea on the east side of a small stream.  No traces of these tombs would have been visible on the surface before a road was cut in the slope and quarrying started."

[3] Cook and Blackman [1971] 48; Vermeule [1964] 244.  A partial bibliography of Boysal's work is in Mee [1978] 151.  Most accessible of Boysal's works might be Boysal [1969] : Katalog der Vasen im Museum in Bodrum: I - Mykenisch-Protogeometrisch (Ankara 1969) 1-28, plates 1-33.  I note that this is available online for reasonable prices.

[4] Vermeule [1964] 245. "Also in 1963 our miniature expedition of three was dispatched by Pennsylvania and Boston Universities to survey the entire valley of Müskebi, to look for the Mycenaean citadel and to record any other noteworthy features or antiquities."

[5] Called out on a nearly impenetrable sketch map in Vermeule [1964] 246.  This is reproduced here in Figure 7.

[6] Zangger et al. [2022] 106.

[7] Online here.

[8] Vermeule [1964] 246.

[9] Zangger et al. [2022] 106, "The nearby river carries much water and sediment at times, as evidenced by the wide channels that have been constructed throughout the village. The river has shifted the coastline seaward by 2.5 km since the Bronze Age."

Bibliography

Bass [1963] : Bass, George F., 'Mycenaean and Protogeometric Tombs in the Halicarnassus Peninsula', American Journal of Archaeology, (67:4) 353-361. Online here.

Cook and Blackman [1971] Cook, John Manual and David J. Blackman (1971): “Archaeology in Western Asia Minor 1965–1970”. Archaeological Reports (17) 33–62. Online here. 1971.

Güterbock [1983] : Güterbock, Hans G., 'The Hittites and the Aegean World: Part I. The Ahhiyawa Problem Reconsidered', American Journal of Archaeology (87:2) 133-138. 1983.  Online here.

Hajnal et al. [2022] :  Hajnal, Ivo with Everhard Zangger and Jorrit Kelder, edd.  The Political Geography of Western Anatolia in the Late Bronze Age; Proceedings of the EAA Conference, Bern, 7 September 2019.  Archaeolingua; Series Minor. Budapest, Hungary, 2022.  ISBN 978-615-5766-54-1. 

Mee [1978] : Mee, Christopher B. (1978): “Aegean Trade and Settlement in Anatolia in the Second Millennium B.C.”. Anatolian Studies (28), 121‒155. Online here. 1978.

Mellink [1963] : Mellink, Machteld J., “Archaeology in Asia Minor”. American Journal of Archaeology 67: 180-181.  1963 Online here.

Mellink [1983] : Mellink, Machteld J., “The Hittites and the Aegean World: Part 2. Archaeological Comments on Ahhiyawa-Achaians in Western Anatolia”. American Journal of Archaeology (87:2) : 138‒141. Online here

Vermeule [1964] : Vermeule, Emily. 'The Early Bronze Age in Caria', Archaeology (17:4), 244-249. 1964. Online here.

Zangger et al. [2022] : Zangger, Eberhard, Alper Asinmaz, and Serdal Mutlu, 'Middle and Late Bronze Age Western Asia Minor: A Status Report', in Hajnal et al. [2022], pp. 39-179.  2022.  Online here.

Determining the shortest Site-to-Shoreline path. Considerations.

 “A common mistake is to assume, implicitly or explicitly, that Bronze Age and modern coastal morphology are essentially the same.” [1]

 

Well (pace Tartaron) we have to start somewhere. 

In order to understand the possible relationship of Bronze Age sites both to the sea and to nodes of trade a good first step would be to determine the straight line distance between each BA site and the nearest seacoast.  By examining a map on which such straight-line links are plotted we can begin to understand the relationship of such sites to the shoreline and the focusing effect that shoreline irregularities have in mapping inland sites to the sea.  First, however, we must have a model of the seashore of sufficient accuracy to allow us to say with some confidence what those distances are and we have no choice but to start with the modern shoreline.  A picture should make these initial themes clear.

Figure 1. Straight lines drawn from BA sites in Arcadia to the nearest seashore.

In this map I have projected (straight-line) each BA site in Arcadia onto the nearest seacoast.   Arcadia is entirely landlocked and its communication with the greater outside world is through neighboring territories; Messenia and the Gulf of Messenia to the S near modern Kalamata, across Triphylia to the W and the Gulf of Kyparissia, and across Achaea to the N (perhaps near ancient Helike).  The primary contact between Arcadia and the ocean is through the southern Argolid near the head of the Gulf of Argos.  It is this concentration of land-to-sea contacts created by the closest gulfs and inlets that I am speaking of.  An accurate representation of site-shoreline direct lines will make this concentration effect clear and it will fulfill another function: that of classification.  We would like an easy way of generating lists of onshore sites as distinct from those inland

But how is this to be done with a database and software?  The first thing that is required is an accurate representation of the shoreline for the entire Bronze Age world.

In the end I decided to make my own.   To be sufficiently accurate the nodes should be no more than 20 m apart for the area being mapped.  The region of Locris is a good example of the technique that I adopted.  Here is an image of the coast of Locris:

Figure 2.  The shore of Locris (Euboea at the top).

First let us superimpose on this map a representation of the database BA sites in this area:

Figure 3.  The north coast of Locris with BA sites as white squares.

Here the sites are represented by white squares.  The problem now is to create a straight line from each site to the nearest seashore irrespective of any land obstacles, mountains, canyons, rivers, etc.  The algorithm adopted should be sufficiently rigorous to be reasonably convincing.  To draw a line to a point withing 30 m of the ‘ideal and perfect’ location should be rigorous enough.  In most cases we can do better than that.  But how should  this be done?

The algorithm I chose was as follows:

a.    Trace by hand the outline of the several land masses

b.   Each node in this line had to be 30 m or less from the next node.

c.    Produce software that would try each (and every) site against all the outline nodes until it found the smallest distance. 

d.   The output of this software would be a set of sql insert statements for a new table, coast, that would hold, for each site, the minimum distance to the shore along with the lat/lon coordinates for the location on the shore closest to the site.

e.    Modifying the production software to generate a distance to shoreline report from the  coast table.  I described this report in my last blog post.

What did this process look like.  In Google Earth Professional I generated a ‘path’ structure that would follow the coast.  When visible, I followed the wet sand mark along the coast.  It looked like this:

Figure 4. Kamares Beach on Sifnos. 
The red dots are interpolated coastal points.

In this figure we see the Paralia Kamares on Sifnos (36.990171° N, 24.678167° E).  I have interpolated a coastline for this beach (blue line).  My interpolated points are the red dots.  The beach is 525 m long (I used the yellow segmented line to measure it) and the dots divide the beach into 67 segments.  Each node (dot) therefore is separated from the next by ~7.83 m.  The next figure shows a detailed view:

Figure 5.  Detail of Kamares Beach.

In figure 4 the yellow measuring line has been removed and the reader will get a better idea of the spaces between the nodes (red dots on the blue coast line).

The site closest to Kamares Beach is C7406, which is a Sanctuary of the Nymphs on Sifnos.  The minimum distance from this sanctuary to the closest shoreline is ~508.8 m.  Given tides, erosion, and other factors the figure should be accurate to +/- 5 m (503.8 to 513.8 m) at worst.

Figure 6. Detail of closest marker to C7406.

In this extreme closeup we see the specific node that marks the closest approach of the shoreline to C7406.  Its next nearest node on the left is  ~15 m.  From C7406 to the closest node is an angle of 332.56°.  To the next closest point on the left the azimuth is 330.81°.  So, an angular displacement of something over 1.75° per node and a lateral error distance of about 15 m. arises from this scheme.   Other sites will provide widely varying parameters of distance and angle but I present this example of C7406 as a typical case and it is this sort of accuracy or better which I have striven for in all the coast tracing exercises I have undertaken.

Which Approach?

I began this extended coastal exercise with the assumption that the entire coastline of the several land masses and islands had to be traced in detail.  In Crete I attempted to trace the entire coastline.  The yellow outline in the next picture represents what I was able to accomplish:

Figure 7.   Crete.  The yellow outline represents my attempt to trace the coast.

Even this (not entirely satisfactory) outline required 8000 points placed by hand.  It required several days of steady work but, in the end, I decided that this approach has serious drawbacks.  First of all the human factor of such eye-straining repetitive work is a drawback.  Second, even 8000 points do not result in the accuracy which I desired to achieve.  The coastline of Crete is about 985 km (985000 m).  Dividing this figure by 8000 gives an average distance between nodes of about 123.1 m.  This is about six times worse than the accuracy given for the Sifnos example above.   There would need to be at least 48000 nodes in the outline of Crete in order to render both a complete outline of Crete and one which was of sufficient accuracy to use for closest shoreline point determination.  I was forced to abandon one criterion or the other and I decided to jettison the idea of creating complete outlines of the landmasses the eastern Mediterranean and just concentrating of those stretches of coastline most likely to be closest to BA sites.

To create an accurate least-distance placing (and with minimal effort) it is necessary to center a circle on each site and note where that circle touches the coast.  Then we draw detailed coastline nodes only at these specific points.  This approach immediately dispenses with having to outline projecting capes and peninsulas since these are highly unlikely to be the closest points to anything.  Here is an example.

Figure 8. Eupalion (C562) in Phocis. Corinthian Gulf

In figure 8 the site of Eupalion/Gouva (C562) is represented by the square rectangle in the center.  Centered on that rectangle is a red circle that just touches the shoreline.  The coastal outline (blue line) is only elaborated in the vicinity of the red circle.  Now it is only necessary to place one or more nodes around the tangent of circle/line segment.  This results in considerable time savings and accuracy is enhances.  In the neighborhood of the intersection of the red circle and the coast it might pay to lay  down points that are much closer together and so ensure greater accuracy.

.  Figure 9.  Southern Phocis on the Gulf of Corinth

In figure 9 C562 (Eupalion) is on the left and two more sites in southern Phocis (C563, C564) are on the right (east).  The coast outline only touches the coast at spots where the closest shoreline has already been determined by circles centered on the sites themselves.  Proceeding in this way means that most the rugged south coast of Phocis will not require modeling in this typical example.

In the example of Crete that I mentioned achieving the desired accuracy with the ‘whole coast model’ approach requires about 48000 points in the shore outline.   As there are 1500+ sites on Crete the computational cost will be 48000 * 1500 or 72,000,000 separate distance computation routine calls.  If we allow only 10 points per site using the previously described circle-focus method then it would require only 15000 outline points and so 1500 * 15000 = 22,500,000 routine calls – a computational savings of about 2/3.   This would run is something under 2 minutes on GoDaddy's servers which is where I run this utility-type software.

Another approach is to take advantage of the fact that Crete is divided into subregions in the Mycenaean Atlas database and so it's possible to model just one region at a time.  This would considerably reduce and spread out the workload into manageable chunks.

Figure 10.  Gulf of Atalantis.  Northern Locris.

 

Figure 10 is an example of the circle-focus method as I applied it to Northern Locris.  Here the sites are represented by white squares.  Each is the center of a circle which extends to the closest coastline.  The blue line is the coast outline.  Notice that it only touches the shoreline where the circles do.  Only those segments are carefully modelled.  The rest of the line is ‘armature’.  The software algorithm adopted for calculating the minimal distance traverses this entire blue outline (node to node) and, for each site, returns that distance along with the lat/lon  pair of that specific closest point on the coast.  In figure 11 we see what that this same region of Locris looks like after processing and with the shortest distance lines properly placed.

Figure 11. North coast of Locris with lines
drawn from sites to nearest seashore.

I represent the nearest approach of site to seashore with a blue line that starts at the site (indicated by a diamond) and ends at the closest seashore point (indicated by a red circle).

These are some of the considerations that I had in mind when performing the task of automating the task of finding the closest seashore to every BA site.  The reader should keep in mind that the ‘shortest distance’ is not from the site, exactly.  It measures the distance from my site marker to the seashore.

In another blog post I would like to discuss what algorithm my software used and whether there are any other useful coastal outline databases available.

 

 

Footnotes

[1] Tartaron [2017] 140.

 

 

Bibliography

Tartaron [2017] : Tartaron, Thomas F.,  Maritime Networks in the Mycenaean World.  Cambridge University Press,  ISBN: 978-1-108-43136-1.  Paperback edition of 2017.