Geodesy is usually defined as the measurement and mapping of the Earth. As a science it is traced back to Pythagoras (6th cent. BC), who was thought to be the first to propose the sphericity of the Earth. Later, Eratosthenes (276 BC– 195 BC) was one of the earliest to attempt to determine the dimensions of our Earth and succeeded with remarkable accuracy.
A controversial aspect of modern geodesy is the claim that many ancient sites were deliberately established at locations that had specific geodetic relationship to each other and/or the dimensions of the Earth. For example(a) in ancient Egypt, from Giza to the Equator is 1/12th the circumference of the Earth, Amarna to the Equator is 1/13th, Luxor 1/14th and Philae 1/15th! Graham Hancock in his Heaven’s Mirror pointed to similar relationships around the globe suggesting a possible world grid. This idea of a world grid has a number of supporters, but is often classified as a ‘fringe’ interest due to the attempt by some to link gridlines with UFOs and their use of the grid as a power source(w).
Possibly related features may be the ley lines identified by Alfred Watkins in Britain(c)(g), the Alesia alignments in France discovered by Xavier Guichard(b) and/or the Heilige Linien of Germany claimed by Wilhelm Teudt(aa).
Heinz Kaminski had claimed to have discovered a megalithic grid system that stretched from Stonehenge across Europe with an east-west and north-south orientation and referred to as the Stonehenge/Wormbach System(h).
Ashley Cowie has published a paper(ac) related to Alesia and the work of Guichard and others, as well as his own investigations.
I should also point out that Marcel Mestdagh also identified a form of road system, laid out in giant ovals with radials in France. At the centre of these ovals was the ancient city of Sens. Philip Coppens informs us [1275.184] that a further strange discovery by Mestdagh was that this ancient road network, centred on Sens, was mirrored by a similar network of roads in England centred on Nottingham!
‘The Way of Virachoca’ in the Andes which runs through Tiwanaku and is oriented exactly 45° west of true north and runs for over 1000 miles, has been studied by Maria Scholten d’Ebneth  in the 1970’s and expanded on by a number of Spanish speaking commentators and is now the subject of an article by Dave Truman(x).
In 1973, three Russians, engineers Valery Makarov and Vyacheslav Morozov along with Nikolay Goncharov, an artist, published in Russian an article with the eye-catching title of Is the Earth a Giant Crystal? (y) This was probably the earliest presentation of an earth grid based on ancient historical sites. A brief history of the earth grid theories that emerged around this time is available online(z). There is now a Russian geodesy website with an English translation(ab).
David Hatcher Childress published his Anti-Gravity and the World Grid  in 1993, with the modest claim that he “proves that the earth is surrounded by an intricate electronic grid network offering free energy.” Obviously, Childress’ understanding of ‘proof’ is different to mine, as the only proof required is the production of some of this free energy, which he has not done.
Tom Brooks has entered the fray with a study of 1500 prehistoric sites and his conclusion that the inhabitants of ancient Britain had a designed a navigation system based on a grid of isosceles triangles(i). Brooks has gone a step further and speculatively claimed that the accuracy of this geometry-based system could only have been designed through “extraterrestrial intervention”(r). This concept is explored more fully in his latest book, Seeing Around Corners: Geometry in Stone Age Britain  and in a series of video clips(s). A more critical view of Brooks’ ideas is also available on the Internet(j).
Some years ago a former employee of a NASA sub-contractor, Maurice Chatelain claimed that within a 450-mile radius of the Aegean island of Delos that 13 mystical sites, when connected by straight lines formed a perfect Maltese Cross(u)!
Others such as Livio Stecchini(d) and Jim Alison(e) using geodetic calculations have identified São Tomé and Cape Verde respectively as the location of Atlantis. I must also include Hugo Kennes, a Belgian researcher with a passionate interest in global grids and sacred geometry(l)(p). Kennes has also informed me of a new Facebook group(q) deal with all aspects of the subject, as well as another(v) that includes submerged cities and other features.
Anyone interested in pursuing a study of this subject might like to look over James Q. Jacobs’ archaeogeodesy website(f) as well as the BioGeometry website (m).
If you have pursued all the links so far, you can pamper yourself further with a paper(k) by William Becker and Beth Hagens(n). Another researcher in this field is Dan Shaw whose website(o) give a good overview of the subject.
Jean-Pierre Lacroix added his weight to the debate with his 1998 paper entitled The Mapmakers from the Ice Age(t).
A global network of sacred sites was also put forward by Rand Flem-Ath & Colin Wilson in The Atlantis Blueprint . This book was intended as a sequel to When the Sky Fell , but generally wandered off into other areas after the first couple of chapters.
I am somewhat sceptical about certain aspects of geodesy, particularly some of the claims of a world grid. However, it does raise many questions that require further study and explanation. In this connection, I would recommend John Sase’s Curious Alignments  as a good starting point.
In February 2020, Frank Maglione Nicholson, Ken Phungrasamee & David Grimason, collectively known as The Nazca Group(ad), published The Nazca Great Circle Map Hypothesis. Their claim is that “The lines and geoglyphs carved into the Nazca plateau represent a map of the Earth. The map is a Great Circle Map: a gnomonic projection with the center of the Earth as its cartographic view point. Each line on the Nazca Plateau represents a great circle of navigation centered at the center of the Earth and encircling the entire planet. The majority of the lines on the Nazca Plateau radiate from five loci of origin called radial centers.” I found this rather esoteric proposition difficult to absorb.
(r) http://www.prehistoric-geometry.co.uk/ [See (i)]
Italian Atlantology can be traced back to the 16th century when Fracastoro, Garimberto and Ramusio, identified the Americas as Atlantis. In fact we should look to the 15th century when Ficino was the first to translate Plato’s entire works into Latin giving medieval Europe its first access to the complete Atlantis texts. Not much happened until 1788 when Carli attributed the destruction of Atlantis to a close encounter with a comet. In 1840, Angelo Mazzoldi proposed Italy as the location of Atlantis and as the hyper-diffusionist mother culture of the great civilisations of the Eastern Mediterranean region. He was followed by others such as Giuseppe Brex(b).
Not much developed in pre-war Italy apart from Russo’s journal which ran from 1930 until 1932. After the war other Atlantis journals was established by Gianni Belli in 1956 and Bettini in 1963. After that there was a wide range of theories advanced by Italian researchers. Spedicato located Atlantis in Hispaniola, Stecchini opted for São Tomé, Barbiero, who although Croatian by birth was an admiral in the Italian Navy nominated the Antarctic as the home of Atlantis before the Flem-Aths published their Antarctic ideas. Bulloni chose the Arctic, Pincherle identified the Mandaeans as the last of the Atlanteans and Monte links Thera with Tarshish.
In recent years the most widely reported Atlantis theory to emanate from Italy came from Sergio Frau who advocates Sardinia as the original Atlantis. However, this idea is not new having been promoted by Poddighe in 1982. Frau has subsequently been supported by other commentators such as Tozzi and Novo. I cannot help feeling that there might be a trace of nationalism underlying this theory, a suspicion that I have held regarding writers of other nationalities.
The latter end of the 20th century saw the development of the Internet which enabled the instant promotion of Atlantis theories, both silly and serious, to a global audience. Italy was no exception, where websites, such as Edicolaweb that are sympathetic to the exploration of historical mysteries emerged(a).
More recently, Marin, Minella & Schievenin had The Three Ages of Atlantis published in 2014. This is an English translation of their original 2010 work. In it they suggest that Atlantis had originally existed in Antarctica and after its destruction survivors established two other Atlantises in South America and the Mediterranean. Perhaps more credible is the theory of Capuchin friar, Antonio Moro who, in 2013, suggested that Atlantis had included Iberia, the south coast of France and the west coast of Italy!
Ocean and Sea are words employed by classical writers in a manner different to our present usage. Originally the Greek word Oceanos referred to the ‘Great River’ that was assumed to flow around the then known world. Stecchini wrote that “the existence of a river Oceanus as an extension of the Nile along the Equator was considered a serious reality in Greek times” (e)
Anton Mifsud has pointed out that Homer used the word ocean for the sea and in fact used the same word for the Tyrrhenian ‘Sea’ (a). Both Seneca and Cicero referred to the Mediterranean Sea as the Atlantic Ocean(b)(c). Diodorus Siculus notes further that the word for ocean has even been applied to the Nile(d). Herodotus noted that Homer also called the Nile ‘Okeanòs’(f), as it was generally believed that it began and ended in an ocean (quoted by J.H. Agnew)[1232.123].
Georgeos Diaz-Montexano made a similar point when he commented that the classical writers had three words for bodies of salt water; pontos (small), pelagos (medium) and okeanos (large). Plato always referred to Atlantis being in a pelagos.
We can conclude therefore that since Plato never used the term ‘ocean’ in connection with Atlantis there is no proof that he was referring to our present-day Atlantic, while in all likelihood he was indicating the western basin of the Mediterranean or the reported large inland sea where the chotts of Tunisia and Algeria are all that remain of it today.
(a) Odysseus x. 508,
(b) Quaestiones Naturales,
(c) Somnium Scipioni
(d) Biblioteca Storica i.