The ancient astro-geometrists thought of the earth as a sphere within the celestial sphere, that is, the sky can be conceived of as being a dome over the earth, meeting the earth at the horizon from a given vantage point. And because the earth wobbles at a rate known to the ancients, 72 years/degree (of 360), they could predict where on earth after a given number of years the stars would appear in the same positions in the sky relative to the horizon. For instance, at the rate of 72 years/degree, after 4,320 years, the stars would appear in the same positions on a given annual date in the sky which would be 1/6th of the way around the globe, the length of the radius of the earth, and so, they calculated the dimensions of the earth, revealing this knowledge in the dimensions of the Great Pyramid of Giza (see article #2 at http://IceAgeCivilizations.com).
The Great Pyramid is a reduced embodiment of an earth hemisphere’s dimensions by a factor of 43,200, the base perimeter length of which just happens to be half a nautical mile, the ancient root of the numbering system for our modern nautical mile mapping system, based on solar time now, because we have the precise instrumentation to calculate distances accurately by solar time, but they didn’t have such precise measuring instrumentation as Harrison’s chronometer, which was invented in the 1850’s, so the ancients used the much slower precession rate of time to measure east west distances (longitudes) accurately, for geometry, meaning earth measure.
Relatively simple ancient mechanical devices were constructed to measure the progession of the constellations through the years because of precession, devices such as the Celtic Cross, Maui’s Tanawa, the Mayan Staff of Power, and the Antikythera Device, and thereby, they could measure earth distances by stars’ positions vis-a-vis the rate of precession, with the celestial “sphere,” its 12 constellations of stars, as the backdrop for measures, so they could boldly navigate to all parts of the globe, accurately mapping it, as they dialed their positions by the stars, simple geometry based on timekeeping as described in article #2. Read on here too under Category Ancient Navigation, to see that the ancients were indeed skillfully navigating and mapping the globe during the Ice Age, clearly evident, yet denied my mainstream science, so please refer this material to your interested associates.
And see http://genesisveracityfoundation.com.