From coconuts to GPS: A brief history of navigation

It's good, but it's no coconut. Image: Getty.

If I ask Google:

It helpfully displays a map of where I used to live:

Google is very good at knowing where I used to be. My phone is constantly keeping track of my location and uploading it to their servers. It has stored my location 579,088 times since September 2013.

Each location stored looks like this:

 “timestampMs” : “1431497952458”,
 “latitudeE7” : 513453840,
 “longitudeE7” : -1015043,
 “accuracy” : 27,

This isn’t that easy to read. The E7 is an instruction to divide by 10,000,000, to reach a traditional set of latitude and longitude coordinates. “timestampMs” tells us that wherever 51.345384° N -0.1015043° E is, I was there at 1,4314,9795,2458 milliseconds after midnight on the 1st January 1970.

Even knowing what each of those numbers represent, we need to do some work to get these back into a human context. By putting the numbers through mapping software I can find out that “51.345384°, -0.1015043°” is Purley Oaks station in South Croydon. By running the timestamp through a conversion system, I can see I was apparently there at 7:19:12 AM on the 13 May 2015. This makes perfect sense, it was part of my daily commute at the time — I’d have been there most days at that time.

Most of the data stored about my location places me somewhere I lived or somewhere I worked. Just occasionally, I do something interesting and the database gets to store whole new sets of coordinates. If I take several years of this data I can produce maps of the sums of my positions over time:

This is my life as latitude and longitude, expressed in a way that can be easily understood by a human. Where I’ve spent any amount of time the map is redder; journeys appear as snail trails across the country.

Google’s algorithms don’t require any of this “coloured in map” nonsense. After a few weeks, your Android phone can make a reasonable guess at where your work and home are, based on where you spend most of your days and where you spend most of your nights. It doesn’t need to ask — that would be intrusive.

To determine a position on a globe while inconveniently being stuck on that globe you need fixed external references. Fortunately the universe is full of these.

One of simpler means sailors used to work out their relative position from destination was a kamal – a board with a hole in the middle. By putting a string through the hole and holding one end of the string in your teeth, you position the lower edge of the board on the horizon and move it further away until the board obscures your target star (typically Polaris — if visible).

An enthusiastic Wikipedia editor showing how the kamal works. Image: Markus Nielbock/Wikimedia Commons.

The length of the string between your teeth and the board tells you your latitude. By knowing the length of string required for certain ports, you could adjust course to navigate to a place. Using nothing more than your teeth, a string, a plank of wood, a star – and the horizon.

In Polynesia (lacking in a helpful pole star) titiro ‘ētū – “star peekers” – made of nothing but coconuts and seawater were used to navigate to specific islands. To use these, you cut off the top of the coconut and make a ring of holes around the base. You then make a hole near the top for the target star and fill it with water up to the holes (with coconut oil to maintain surface tension). You look through the device at the star at its highest point; if the water inside the device is flat, you are on the same latitude as your destination. The stars will guide you with the simplest of tools, if you know how to use them.

Progression east-west (longitude) can be understood if you know the difference between high-noon on a clock set at a fixed location (Greenwich) and a clock set at the current location. Each hour difference represents 15° of travel longitudinally (1/24 of 360°). Simple enough, if you have a clock that can keep time on the ocean – but that was a complicated problem to solve. Before that, all sailors could really do is line up on the right latitude and go for it.

To make use of more markers than the sun and North Star, you could use nautical almanacs and sextants. These almanacs were essentially large lists of what celestial objects should appear at certain points of the sky, and at what time they can be expected to do so. By using the sextant to compare predicted appearances to actual locations, you can determine the distance to fixed positions.

The Global Positioning System (GPS) has mostly replaced the need for these tables. Reliable but not available on-demand stars have been replaced by artificial celestial bodies that spend their whole lives yelling about where they are and what time they think it is. By comparing signals from several different satellites to the time your GPS device thinks it is, you can triangulate your position on the earth within a few meters.

Few mobile phones contain true GPS: mostly they use aGPS or WPS. aGPS uses the resources of the mobile network to speed up reconciliation based on fragmented signals, but WPS (Wireless Positioning System) is something different altogether. It takes advantage of the fact that we littered our world (especially urban areas, where GPS struggles) with millions of radio location beacons, in the form of Wi-Fi access points.

While the vans with the weird cameras were taking pictures of every road in the world, they were also mapping the radio landscape we have made: each house with a Wi-Fi access point, broadcasting a unique identifier. By mapping these to a true GPS reading, location services can provide a guide to any device with a wifi chip. If you read Device #1053443 with 50 per cent strength and Device #10232321 with 74 per cent strength and Device #24324239 with 60 per cent strength, the chances are you are “here” — the most likely place where those signals converge at that strength.

These vans are no longer necessary: while walking around your phone will pick up on any new or unknown access points. With sufficient logs of these devices, their location can be deduced by comparison to known devices and used for future navigation. As well as recording our every step, our phones are automated radio cartographers. This is still ultimately working on similar principles to the nautical almanac and sextant, it just has a much larger look-up table and uses thousands of man-made stars to light the way.

As navigation has become much easier there is also the risk of becoming too dependent on what might turn out to be fragile technology. The US Navy is currently re-introducing celestial navigation training. so that its sailors can figure out where they are in the event of an attack on the GPS system. After the apocalypse, we might find ourselves getting around by holding a bricked phone up to the horizon and measuring the length of the headphone cord to our teeth. 


The smartphone app placing virtual statues of women on the map

A virtual Edith Wharton in Central Park, New York City. Image: The Whole Story Project.

If you’re a woman, then in order for you to be immortalised in stone, bronze or whatever once you’ve shuffled off this mortal coil, you should either have royal blood or be willing to be sculpted naked. That is the rule of thumb.

A statue that actually celebrates a woman’s achievements is a rare sight. Writing in the New Statesman last year, equality campaigner Caroline Criado-Perez found that out of 925 statues in Britain, as listed by the Public Monuments and Sculpture Association, only 158 are of solo women. Of these, 46 are of royalty, including 29 of Queen Victoria. Fourteen depict the Virgin Mary.

There are signs of change, albeit slow. The suffragist Millicent Fawcett is set to be honoured with a statue in Parliament Square, where currently all 11 of the statues are of men. (They include Nelson Mandela and a nine-foot Gandhi.) The monument is to be unveiled next year to celebrate the centenary of British women receiving the right to vote.

Elsewhere, the late comedian Victoria Wood is being honoured with a statue that’ll be erected in Bury, Greater Manchester. In the Moss Side area of the city, a statue of Emmeline Pankhurst will be unveiled in 2019. Unlike the Fawcett one, neither of these is expected to receive public money, relying on crowdfunding and other sources instead.

So how many more statues of women, regardless of how they’re funded, would we need to build in order to reduce the gender gap? Well, according to Jonathan Jones, art critic at the Guardian, the magic number is: zero.

Jones’s argument, back in March, was that building statues doesn’t advance feminism, but simply traps us in the past. He wrote:

Statues don’t hold public memory. They politely bury it. These well-meaning images melt into the background scenery of our lives.

Whether this is empirically true is questionable, but it’s true that we tend not to erect them as often as we used to anyway. This is partly because there is less space available for such monuments – a noticeable disadvantage cities of the present have compared to those of the past. In order to reduce the imbalance, statues of men would probably have to be removed; many would no doubt be okay with that, but it would mean erasing history.

One partial answer to the problem is augmented reality. It can’t close the gender gap, but it could shine a spotlight on it.

To that end, an advertising agency in New York launched an app at the beginning of May. The Whole Story allows users to place virtual statues of women on a map; other uses can then view and find out more about the individuals depicted at their real-world locations, using their smartphone cameras.

Currently, users have to upload their own virtual statues using 3D-modelling software. But going forward, the project aims for an open collaboration between designers, developers and organisations, which it hopes will lead to more people getting involved.

Contributions submitted so far include a few dozen in New York, several in Washington and one of Jane Austen in Hyde Park. There are others in Italy and the Czech Republic.

Okay, it’s an app created by a marketing firm, but there are legitimate arguments for it. First, the agency’s chief creative office has herself said that it’s important to address the gender imbalance in a visual way in order to inspire current and future generations: you can’t be what you can’t see, as the saying going.

Second, if the physical presence of statues really is diminishing and they don’t hold public memory, as Jones argues, then smartphones could bridge the gap. We live our lives through our devices, capturing, snapping and storing moments, only to forget about them but then return to and share them at a later date. These memories may melt away, but they’ll always be there, backed up to the cloud even. If smartphones can be used to capture and share the message that a gender imbalance exists then that’s arguably a positive thing.  

Third, with the success of Pokemon Go, augmented reality has shown that it can encourage us to explore public spaces and heighten our appreciation for architectural landmarks. It can also prove useful as a tool for learning about historical monuments.

Of course no app will replace statues altogether. But at the very least it could highlight the fact that women’s achievements are more than just sitting on a throne or giving birth to the son of God.

Rich McEachran tweets as @richmceachran.

Want more of this stuff? Follow CityMetric on Twitter or Facebook.