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The evolution of mapping technology from cartography to GPS

The tech behind finding the right path has evolved to almost pinpoint level accuracy over the years, thanks to contributions from Ptolemy as well as the Sputnik

Maps, in one form or another, have been crucial in the story of human civilisations. Travelling vast distances, prehistoric man communicated the details of the route back to the people left behind, and that is where mapping began in its true sense. Over the years, maps have evolved to a point where we can trust our smartphone navigation apps more than we would trust our own sense of direction. In fact, today everyone with a smartphone can become a cartographer with programs such as Google maps local guides. But this journey started long ago, when most of the roads in the world were unmapped.

catal huyuk
Some archaeologists have speculated that this represents a leopard skin

Tracing the horizon

Baylonianmaps
Another contender for the earliest map available

While it is well known that the Egyptians had made maps and city plans on papyrus long ago, very little evidence of the same made it to our time due to the fragile nature of the medium. The earliest known instance is more of a town plan that was discovered in the 1960s. The wall painting discovered there by James Mellaart was carbon dated to 6200BCE and it appears to represent a crude layout of the town and the nearby stratovolcano Mount Hasan. While there is speculation whether this is a map at all to begin with, this serves as an interesting example of what mapping was all about back then – subjective interpretation.

Another helpful instance is a Babylonian map from about 600 BC. In the representation, Babylon was represented at the centre of the map, which was a common practice of the time, while several other cities like Assyria and Urartu were represented around it.

A science

It was the Greeks who pushed cartography from a subjective art-form to a science necessary for the society. Eminent scholars like Ptolemy, Herodotus, Anaximander and Eratosthenes had significant impact on the field of geography. Anaximander, for instance, was the first to draw a map of the known world, while Pythagoras of Samos speculated about a spherical Earth with a central fire at its core. These maps were made and improved over the years. Based on Anaximander’s map, Hecataeus of Miletus created a new, more expansive map.

As the next major upgrade to mapping techniques, Eratosthenes incorporated parallels and meridians in 2nd Century BC, which indicated his understanding of the spherical earth theory, something some of us are apparently still struggling with. Around a century later, Posidonius, in his work “about the ocean and the adjacent areas” calculated earth’s circumference at 240,000 stadia, close to the actual value of 24,901 miles.

A tool

While Ptolemy’s original maps were never found, he had described, in his work, a system of using latitudes and longitudes as well as astronomical observations from particular areas to develop better maps. His work was informative enough for cartographers of 1300AD to recreate the Ptolemy map. This was the first time cartography was a numerical science.

PtolemyWorldMap
The Ptolemy map would guide cartographers for years

Over the next few centuries, the mapping technique didn’t change much. However, maps were increasingly detailed as the known world was explored further. The next big cartographic milestone came with the popularisation of printing.

Around the 16th century, tools like the pendulum clock, telescopes, as well as established theoretical tools like the logarithmic tables, calculus, law of gravity helped scientists make significant progress. A major improvement came through the publication of Mercator’s maps. These maps were the very first to take into account the spherical-to-flat conversion that needs to happen when representing earth on a flat surface. As a result, these became crucial tools for naval navigation because of the straight lines of latitudes and longitudes.

Mercator 1569
Mercator Projection represented the most accurate spherical-to-flat depiction of the Earth

In the 18th century, mathematics and astronomy, particularly the work of Sir Isaac Newton, gave a boost to the method of determining longitude to the degree. Eventually, developments in lithographic and photo-chemical technologies led to maps with greater levels of detail being printed. But the next true revolution in mapping came in the 20th century.

A weapon

Sputnik 1
Sputnik 1 can effectively be given credit for kick-starting modern mapping technology

Most of early 20th century, advances in printing and photographic technology allowed for physical maps to become more accurate. But as the 1950s passed, computer-based mapping software saw a rise in development, especially due to progress in nuclear weapon research. After Russia launched the Sputnik 1 in 1957, two American physicists at the Johns Hopkins Applied Physics Laboratory (APL), decided to monitor its radio transmissions. Thanks to Doppler effect, they realised quite soon that they could track the location of the satellite along their orbit. The very next problem they got working on was the inverse – tracking the location of the user if that of the satellite is known. This led to the development of the TRANSIT system, the first satellite navigation system which was used by the US Navy and tested successfully in 1960.
The next decade saw multiple systems like the Project 621B, Transit, Timatian, SECOR use different approaches to fix the exact location problem. While none of them entirely succeeded, a superior system was eventually developed using the best technology from each of these, resulting in the Navstar-GPS system. Keep in mind that all of this was restricted military technology, which was about to change soon due to a tragic event.

A technology

After a Korean Air Lines Boeing 747 was shot down for straying into USSR airspace in 1983, US President Ronald Reagan issued a directive instructing GPS to be made available for public use. For quite a few years, the highest quality signal was still reserved for military use while the civilian signal was subjected to ‘selective availability’ or SA.

Claas Baseline
A transportable station equipped with a single-frequency GPS receiver and a radio antenna

Ground-based navigational systems that were being used so far by civilian services had poorer accuracy and greater costs involved. While this could be solved with GPS, the S.A signal was not good enough for the same. The United States military received multiple requests over the years from the Federal Aviation Administration (FAA), United States Coast Guard (USCG) and the United States Department of Transportation (DOT) to remove the restrictions of S.A but it was refused on the grounds of security.

The 1980s and 90s saw the gradual rise of Differential GPS (DGPS), which increased the accuracy of the S.A signal by taking into account the offset in the poorer signal, along with efforts by the US Coast Guard to make high-quality signals available across the US. Eventually, most GPS vendors were offering receivers capable of using DGPS signals. By the mid-90s, DGPS was being used enough to render the S.A signal’s purpose ineffective in the US. Additionally, during the Gulf War, the US forces had to use a large number of civilian receivers. These factors saw to the removal of the S.A restriction with an executive order from President Bill Clinton in 2000. By then, DGPS had evolved to provide more accuracy than a non-SA GPS signal, to the point where the best implementations offer an accuracy of up to 10cm.

Around the same time, Russian President Vladimir Putin paid special attention into reviving GLONASS, the Russian equivalent of GPS which had followed a similar trajectory to GPS until it fell into disrepair at a time of Russian economic crisis. By 2006, the signal was available for civilian use and by 2007, all restrictions were lifted.

A way of life

Over the next few years, commercial usage was heavily promoted for both GPS as well as GLONASS. The Russian government even implemented import duties specifically targeted at GPS devices to generate international interest into the GLONASS system. Both systems have seen technological upgrades and are due for more upgrades in the coming years.

Thanks to smartphones and now, cars with navigational capabilities, maps are a part of our lives in a much more integral way than we would have imagined even 10 years ago. Somewhere, along the way, we have developed a habit to not rely on our own sense of direction. Instead, listening to a computerised voice dictating your very steps seems to be a highly reliable way of finding the correct path. Cartography and navigation, as a field of technology, truly reflects the transition to an absolutely technology enabled evolution of humanity.

This article was first published in the June 2017 issue of Digit magazine. To read Digit’s articles first, subscribe here or download the Digit app for Android and iOS. You could also buy Digit’s previous issues here.

Arnab Mukherjee

Arnab Mukherjee

A former tech-support desk jockey, you can find this individual delving deep into all things tech, fiction and food. Calling his sense of humour merely terrible would be a much better joke than what he usually makes.