From the Great Pyramids to GIS/GPS

November 12, 2019  - By 4 Comments

Connection to the Stars

Pyramids of Giza taken from the International Space Station. (Image: NASA)

Pyramids of Giza taken from the International Space Station. (Image: NASA)

The Great Pyramids still cast their long shadow upon history. It’s been said that even Time kneels before them. They are monuments to the state-of-the-art technology of the builders using their most advanced astronomy, engineering, mathematics and trigonometry as a testament to their understanding of the world.

They are monuments to the builder’s state-of-the-art technology at the time using their most advanced astronomy, engineering, mathematics, and trigonometry as a testament to their advanced understanding of the world.

The pyramids’ corners align perfectly to the four cardinal points. Shafts on the north slope point towards the circumpolar stars, the so-called “Imperishable Ones” because they never set beneath the horizon. The Great Sphinx, eternal companion of the pyramids, is perfectly aligned to face the rising Sun on the morning of the summer solstice.

These constructs defined the physical framework of their cosmogony — ancient Egypt’s center of the world — their prime meridian and equator. References of place were in terms of direction and distance from the pyramids.


The word meridian is a Latin derivative of meridiem, as in a.m. and p.m., meaning midday. The moment is marked by the sundials’ shadow being neither to the west nor to the east and is directly in the middle. It marks an imaginary line running from north to south. The Prime Meridian is synonymous with Greenwich Mean Time (GMT), Universal Time Coordinate (UTC), or the military time zone Zulu.


Bitter Waters, the oldest map in the world. (Photo: British Museum)

Bitter Waters, the oldest map in the world. (Photo: British Museum)

In Mesopotamia in 600 B.C. is a map carved into a clay tablet depicting Babylon in the center surrounded by a circular ocean marking the edge of the known world. Beyond the ocean are eight projections emanating like sunrays. Four of them point to the cardinal directions and the other four towards celestial bodies with mythological significance.

This map, called the Bitter Waters, the name of the circular ocean, is considered the oldest in the world; and thus, the first official cartographer forged together the geography of the physical world with that of the cosmos.

Early maps had few frames of reference. If you wanted to know your whereabouts, you had to already know where you were, otherwise, you’d need the expertise of a seasoned guide.

Celestial bodies were the primary means for finding one’s way, the main one being the Sun, especially at daybreak. In fact, for thousands of years the importance of the sunrise was so essential to getting oneself pointed in the right direction that to this day it remains the principle word for that action.

Consider the following. The way a map is pointed is how it is oriented. If someone is lost, physically or consciously, that person is disoriented. The skill of traversing overland is orienteering. These all stem from the Latin word for east, orientalis; hence, the civilizations beyond Byzantium were considered the Orient, and likewise, the word Asia comes from the Phoenician word for sunrise, Asu. Thus, setting out on a journey required waking up with the sunrise and marking the direction of the shadow and then dead reckon along that line due west, or opposite the line due east.

In fact, many ancient maps were oriented toward the east such as the Mappa Mundi mentioned later in this article. At night, the North Star and knowledge of the constellations were used for travel; but during the day, north was just a general direction. North was derived by drawing a right angle perpendicular to the line between the two points of sunrise and sunset. The term for North under Roman rule was pars caeli septentrionalis, which translated means, The part of the sky towards the seven stars, referring to Ursa Major and Minor. North was not of much use during the day until the invention of the magnetic compass.

The Early Superpowers and the Great Sea Race

The trade routes along the Silk Road collapsed after the fall of Byzantium in 1453, and where there is chaos there is also opportunity. Reestablishing dependable trade with the east was worth billions. Finding a sea route to become Europe’s source of spices and goods was too alluring. The “Sea Race” of nations had begun.

Cantino Planisphere. (1502) (Image: public domain)

Cantino Planisphere. (1502) (Image: public domain)

Portugal won the first round of the Sea Race claiming islands to use for trade routes rounding the Cape of Good Hope in 1488 and reaching India in 1498. Columbus, sailing under the Spanish flag discovered the Americas in 1492. The Mappa Mundi by Spanish explorer Juan de la Cosa in 1500 is the first map to show the Americas.

Navigational maps were closely guarded national secrets; so much so, the Duke of Ferrara hired a spy, Albert Cantino, to steal a Portuguese nautical map, which is now named in his honor, the Cantino Planisphere, and it shows the emerging knowledge of the newly discovered world. It also marks the evolution of travel using celestial navigation. America, unnamed at the time, was a closely guarded secret by the Spanish and of top national interest.

Portugal and Spain dominated the oceans for most of the 15th and 16th centuries to the point that the world was divided between the two along a meridian known as the Tordesillas Line splitting the world between the two superpowers.

Technology Ignites the Golden Age of Sailing Ships

Thanks to early navigation of the Portuguese and the Spanish, the magnetic compass and the sextant came into use, allowing more precise calculations of latitude improving navigation. Cartography and surveying improved as a result. Ingenious approaches for telling time at sea were invented. One method used Jupiter’s four primary moons as a clock.

England, over 100 years late to the global expansion entered the Age of Sail in 1600 when Queen Elizabeth signed the charter establishing the East India Company (EIC). Contrary to both the Portuguese and Spanish models which were funded by their monarchies, the English created a profit-sharing corporate model, which would ultimately account for half of all the world’s trade.

The EIC remains the most profitable company in history (inflation adjusted), but the costs of running such a vast enterprise were also great. The EIC lost nearly 220 ships. Every ship lost was the loss of a captain, the crew, the cargo, and the ship itself. Shipping was a costly venture. Not counting pirates, storms and war, the primary cause of shipwrecks was incorrect location. Distances could be off by hundreds of miles, enough to end up in the shallows or the rocks.

The problem wasn’t latitude. That could be determined with a great degree of certainty using angular measurements of the sun and celestial bodies above the horizon. Longitude was the culprit. Knowing position on an east west axis proved much more difficult. Longitude was thought to be an astronomical problem, and in order to solve it King Charles II established the Royal Observatory in Greenwich, England in 1675, which happened to be at the height of Europe’s scientific revolution, the primary scientist at the time being Isaac Newton.

However, as many of the greatest minds attempted to solve the problem, none were able to do so. Thirty years’ later the Royal Society presented the challenge to the public offering a reward of £20,000, which is equivalent to approximately $3.1 million in 2019. It was known as the Longitude Act of 1714. The solution finally came in 1736.

The John Harrison Marine Chronometer.

The John Harrison Marine Chronometer. (Photo: National Maritime Museum, Greenwich)

John Harrison, a clockmaker, understood that space and time are inextricably connected. Longitude was solved by having two chronometers, which literally means an instrument to measure time. One chronometer was set to local time each day at noon. The other was set to Greenwich Mean Time. The difference in hours between the two pinpointed the time zone and the corresponding longitude. The original time zones were not the political ones represented today. There were 24 of them around the circumference of the earth and each time zone corresponded to a different letter of the alphabet.

Time zones traverse in increments of -1 hour to the west and towards the east +1 hour for 12 hours in each direction totaling 24 in all. The Greenwich Observatory lies within time zone 0 which is the military time zone Z. In the military phonetic alphabet Z is Zebra but it used to be Zulu.. The more precise time could be measured, the more accurate the position, thus, location coordinates are measured in degrees, minutes and seconds.

Today, the world’s primary chronometer is called the Master Clock and is housed at the United States Naval Observatory (USNO) in Washington, D.C. The USNO’s primary mission is position, navigation and timing (PNT). The grounds of the USNO is the home of the Vice President indicating the importance time is to commerce and the welfare of a nation.

GPS satellites set their internal clocks to the USNO Master Clock. PNT is so precise location can be determined down to the sub-millimeter level. Every smartphone’s geolocation is tied into this network. The U.S. Naval Observatory Master Clock has a phone number, (202)762-1401, and every 15 seconds the voice of Time proclaims the exact moment, translating the decay of cesium-133 into the same language of the pyramids, the Sphinx and Stonehenge.

A final thought. Heraclitus said we cannot step into the same river twice. The river changes by the flow of itself. But, Time itself is a river and with each passing moment our lives forever change. Look back. It is the past — the place of regret and glory. Look forward. It is the future where hope and fear reside. Look at the present. It is the only place we are.

William Tewelow, GISP

About the Author:

William Tewelow is a manager for the Federal Aviation Administration (FAA). He is a graduate of the FAA management fellowship program and a mentor with the FAA's National Mentor Program. While on special assignment to the U.S. Department of Transportation, Tewelow led the project to crowdsource the National Address Database for the White House Open Data Partnership. He is a geographic information systems professional (GISP) and a Maryland Scholar STEMnet speaker. He has a degree in geographic information technology and intelligence studies from American Military University and is currently enrolled earning a degree in Organizational Leadership. Tewelow retired from the U.S. Navy after serving 23 years as a geospatial and imagery intelligence specialist, a naval aviator, a meteorologist and a tactical oceanographer. He was among the first in the nation to earn a Geospatial Specialist Certification from the U.S. Department of Labor while working at NASA Stennis Space Center in Mississippi.

4 Comments on "From the Great Pyramids to GIS/GPS"

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  1. Alain Tanguay says:

    Thanks for this article.

    • William Tewelow says:

      Thank you for reading Alain and please, feel free to connect with me on LinkedIn. I always support geospatial enthusiasts. Kind regards.

  2. Eric Foster says:

    Great article that brings GIS and geospatial technology issues relevancy and ties them to our historical world. It’s Amazing how much knowledge we have amassed throughout history and amazing how much we have lost and regained. Best regards.

  3. Craig Roberts says:

    Great article William. I will surely share with my students, but I do have a question. If the Egyptians aligned the pyramids with the north star around 5,000 years ago, the Earth’s spin axis has subsequently precessed considerably (26,000 yr cycle). Does this mean that currently the pyramids do not align with the north star due to this precession? Thanks

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