Three words that replace coordinates on a map

By MUNGAI KIHANYA

The Sunday Nation

Nairobi,

01 November 2020

In September 2009, I explained in this column why I believe I am the only person in the whole world with the name Mungai Kihanya. There are very many Mungais and a few Kihanyas, but there is only one Mungai Kihanya – me!

In Kenya, it is customary for people to have three names – or, as Philip Ochieng would insist, three words in their name. In this case, the chances of meeting two people with the exact same three names are extremely low.

Still, I had two classmates in school who shared three names. Both were called James Kaberia Mbugua. They were not related. In fact, one hailed from Murang’a and the other from Kiambu.

There uniqueness of three words has been applied ingeniously in navigation. In 2013, a company called What3Words came up with a brilliant idea. They subdivided the entire surface of the Earth into squares measuring 3m by 3m.

Each of these squares was assigned a unique set of three words. For example, the main entrance to the Nation Centre Building is designated “flight.changed.tabs” while the rear entrance is “decorated.trying.fizzy”.

The question that begs an answer is: are there enough words to cover the entire surface of the Earth? To find out, we start by working out the number of 3m-by-3m squares required.

Knowing the diameter of the planet (about 12,800km), it is easy to calculate its surface area (four times pi times the square of the radius). The answer is about 515 million square kilometres. This translates to about 515 trillion square metres.

This is then divided into 3m-by-3m square (9 square metres); so, there are about 57 trillion blocks to assign three words to.

Next, we ask: how many words are enough to make 57 trillion unique sets of three words each? The answer is approximately cube-root of 57 trillion. That is, about 39,000. Are there that many words?

Well, the Oxford Advanced Learner’s Dictionary has over 185,000 English words. Therefore, getting 39,000 out of it is quite easy. In fact, one can choose the easier ones.

Indeed, the What3Words map is available in 43 languages, including Kiswahili. The main entrance of Nation Centre is also “sidhani.kutafutia.wamiliki” in the Kiswahili version.

In other maps, the same location is identified by its coordinates (-1.283256, 36.822345). So, which is easier to remember: three random words or the string of digits in the coordinates?