Archaeogeodesy can be defined as that area of study encompassing prehistoric and ancient place determination, point positioning, navigation (on land or water), astronomy, geodynamic phenomena, and measure and representation of the earth. Archaeogeodesy, by combining fundamental astronomy, geodetic knowledge, applied mathematics, accurate positional data and archaeology, presents a methodology for investigating the placements, interrelationships, spatial properties, arrangements and architecture of prehistoric sites and monuments.
As a new area of inquiry archaeogeodesy presents unique avenues of assessing ancient understandings of geography, of place, and of the earth and the cosmos as evidenced by archaeological remains. Archaeogeodesy studies have revealed some very startling results that may alter our views of prehistory. Some of these results are presented later in this series of articles.
We generally regard temporally, spatially and culturally diverse ancient monuments as unrelated. The many pyramids of Egypt, whether stepped, bent, or true, have interrelationships, however understudied. What of the other pyramids dispersed the world over? Few would argue no relationship between neighboring earthworks in North America, for example, yet similarities to neolithic mounds and circular embankments around and near the stone circles of the British Isles go relatively unnoticed. Visitors to Stonehenge who notice the surrounding earthwork are unlikely to postulate connections to monuments as distant as Ohio. Yet the question, "Did a broadly defined mound-pyramid complex originate and diffuse from a single source or cultural tradition?" is difficult to entirely ignore. With modern cartography, geodetic science and mathematics the question can easily be addressed.
Knowing where you are and wayfinding have always been fundamental tasks of human survival. Of modern geodetic tasks navigation and surveying are the most common and familiar. To methodically explore and chart the earth the need to know the form and size of the geoid arises. Geodetic capabilities involve a determination of coordinates on land or at sea as well as in space with respect to terrestrial reference. Point position is resolved by measurements linking terrestrial and celestial reference in a triangulation net. True and accurate knowledge of celestial dynamics and the spatial properties of the solar system are fundamental to the practice of geodesy. Likewise geodetic arrangement of prehistoric monuments could demonstrate fundamental and/or complex astronomic and cosmographic knowledge not previously ascribed to ancient and prehistoric cultures.
Although five thousand year old references to the true shape of the earth are known from Mesopotamia, twenty centuries later Homeric poems refer to the earth as a disc. Historians credit Pythagoras and Thales of Melitus with hypothesizing a spherical earth. The accuracy of Eratosthenes' determination of the earth's magnitude (by measuring a meridian arc from Alexandria to Assuan) remains debated today. Arabians measured a two degree meridian arc near Baghdad in 827 A. D., determining the globe's size with an error of plus ten percent. In the Netherlands in 1617 W. Snellius deduced from an astronomically determined meridian of over one degree a circumference of 24,010 miles. Seventy years later Isaac Newton recognized that the earth is an oblate ellipsoid flattened at the poles. Not until after 1850 was a near accurate ratio determined. The most recent International Astronomic Union definitions (based in part on satellite measure) rate the equatorial radius at 6,378,140 meters (24,901.4726 miles in circumference) and the flattening factor at 1/298.257. The most recently accepted data is available on the Cosmographic Values Index page.
Written history is a fragile, incomplete and recent record at best. The famed burning of the library of Alexandria or of Native American libraries exemplifies the easy destruction of vast stores of accumulated knowledge. The few surviving prehistoric Mayan codices evidence astronomic periodicities in the date sequences. These recent discoveries demonstrate the advanced astronomic knowledge of the Maya and illustrate the magnitude of lost knowledge. History is subjective and readily altered to suit conquerors. Furthermore, translations are limited by the conceptual limitations of both language and translator. In contrast, the archaeological record is objective, durable and also not temporally bounded. True history is far more than written records and it is never entirely lost; it leaves abundant evidence awaiting those who care to inquire.
Dating from 5,700 to 5,200 years ago, three of the oldest surviving buildings on the earth, the Newgrange, Knowth and Dowth tumuli, dominate the landscape of the Plains of Kildare in Meath County, Ireland. Every year at