The Problem With W3W

Photo by ali elliott on Unsplash

Navigating is tricky. Even in fair weather and with good visibility, getting from point A to B requires some degree of skill and attention. The consequences of navigating poorly can easily result in exhaustion, injury, or worse in adverse weather conditions. Today, technology augments user skill and assists in many scenarios, but it’s far from an easy or complete solution to the problem.

Modern mobiles can and do save lives on hills and in remote places. Even on a good day, outdoor navigation can often be responsible for preventing disaster and keeping user’s on track. Compared to similar devices a decade ago they’re an order of magnitude more capable and more reliable. They should be commended as part of a complete package where they’re often vilified for mere use in online forums and social media in particular.

Looking at how they’re used and in what scenario they are deployed is a more interesting question to ask, however. Highly capable hardware can tempt users into depending on a device entirely to stay safe and find their way through remote places.

Relying on any regular consumer device to take up a safety-critical role is a dangerous and risky strategy. Neither the hardware or software of a mobile application has ever been designed to take up this role. Often, one or both are less than capable of taking up the challenge and, in many cases, even less capable than advertised.

Navigation Software for Mobile Devices

In 2013 What3words(W3W) launched a navigation and location finding service that quickly spread in adoption and day-to-day use. Designed to make communicating GPS coordinates more convenient, easier, and foolproof; W3W regularly boasts of performing life-saving interventions in safety-critical scenarios through their website and marketing materials.

Source: what3words

Since its launch, the app has seen tens of millions of downloads across both mobile app platforms. Today, more than 100 UK emergency services use the application to communicate locations between callers and crews.

It’s precisely this emergency use case, however, that is causing concern amongst researchers and mountain rescue teams.

How What3words Works

The technical solution of W3W is an ingenious one. By assigning 3×3 meter squares to divide up the earth’s surface, the app can assign a unique and almost random three-word address to each location. With your phone’s location-finding capability, your device can look up its current address and provide the three-word phrase that corresponds to precisely where you are on the grid.

These three-word addresses make locations easy to communicate, whether describing them verbally to another English speaker, sending them via text, or linking with a hyperlink over messenger.

The service doesn’t need continuous data to support finding addresses. An algorithm uses GPS data to convert conventional latitude and longitude addresses into the corresponding three-word phrase using a database stored on the device.

Compare, for example, the address for the centre of Edinburgh:

  • Lat/lon:
    • 55.95324064637, -3.189719243209
  • What 3 Words:
    • Headed.reach.prep
Source: what3words

Easier to type in, easier to describe, and faster to look up than the cumbersome GPS coordinates provided by the phone. In day-to-day use, this location finding tool is more attractive, easier to use, and relatively foolproof for both recipient and sender.

It’s when the application is used in a safety-critical role, some if its more glaring errors could turn the platform from a powerful ally to a dangerous enemy.

The Problems With What3Words

One of the platform’s biggest and most dangerous problems lies in the potential for similar sounding words to lead to vastly different locations. In daily use, this isn’t an issue that should regularly prove catastrophic.

It may simply lead to a longer walk or drive, or maybe a diversion that adds a few minutes on to your journey. Most can forgive such rare small errors. Non-recurring much more regularly than advertised however, it’s a well-documented issue that can have devastating potential in emergencies.

The platform’s solution to the homonym problem is to group similar sounding words with vast distances between them. Doing this allows for potential mistakes to be easily noticed and amended before users take action. For the platform too, it’s a solution that can be easily implemented by an automated algorithm rather than manual intervention.

Consider, for example, while we found Headed.reach.prep in the centre of Edinburgh:

  • Headed.reach.preps is located in Western Australia
  • Head.reach.prep is in Beverly Hills, California

A widely spaced grouping is a fantastic technical solution and one that should alert users with an estimated time of arrival in days rather than minutes. However, real-world use has turned up situations where the algorithm’s capabilities aren’t as complete or as capable as advertised.

Users of the app have quickly found an absurd number of gaps and omissions when used to address locations in practice. Similar sounding names were being separated by just 5, 10, or 50 miles at many points. The delays caused by these phrases would be significant enough to add vital minutes onto a response time, but potentially small enough to go unnoticed noticed by users.

Spurred on by these user reports, Cyber security researchers posted a detailed breakdown of the algorithm, detailing precisely how it performs and the chances of falling into one of these pitfalls.

In their analysis, researchers estimated the odds of an address having a similar sounding twin within 20 kilometres to be less than 1 in 1000. W3W published data and marketing advertises these odds at less than 1 in 2.5 million.

Examples of W3W mixups

Trying to describe an incident on the correct side of the Clyde could lead to disaster for crews using a 3-word address separated only by a plural.

Potentially worse still: Two sides of Beinn Maol Chaluim separated by about 2km and a sizeable glen in between. In poor visibility, it would be easy to guide crews up the wrong slope.

Stumbling across an address with a similar sounding twin nearby is an unlucky occurrence. At odds of less than 1 in 1000, however, and with the booming popularity of the app, it’s one that will happen fairly regularly in the real world. When it does, the consequences can be potentially fatal with potentially fatal consequences.

In practical use, mountain rescue teams have found a number of issues resulting from users relying on the proprietary app to pinpoint their location. Mark Lewis, head of ICT at Mountain Rescue England and Wales (MREW), cited several incidents to BBC news where rescue teams were sent to the wrong location as a result of spelling errors and difficulties with local accents.

Scottish Mountain Rescue has also reported seeing similar incidents, highlighting the need for users to gain self-reliance and the skills necessary to navigate remote places safely.

It’s this over-reliance on “smart” devices that represents one of the biggest dangers to the general public today. Deepening this reliance more with a proprietary navigation solution that turns navigation skills into a black box solution can only ever serve to compound this problem.

What3words Vs Lat/Lon

What about the problem that W3W is attempting to solve? A 3-word address is demonstrably easier to communicate than the long string of numbers churned out by a GPS device. The coordinates posted above for Edinburgh city centre, all 27 digits of them, are longer than a credit card number and similarly prone to mispronunciation, digit errors, and simple typos. Surely a 3-word address is going to improve on that.

Technically, yes. But also no. The argument against the raw data that comes out of a GPS device is facetious at best. Eleven digits after the decimal place is not only a degree of precision that is absurdly unnecessary; it’s one that the GPS embedded on your phone can’t really hope to achieve.

The address listed above is good enough to point to a period on a page of a book left open and read from low earth orbit. For comparison:

  • 55.9532, -3.1897 is functionally identical, getting you well within the precision range of a W3W address
  • 55.952, -3.189 will get you well within throwing distance. Narrowing the search range down to less than a single street
FAA radiotelephony alphabet and Morse code chart

There’s no doubt that numbers are less visually attractive or as easy to remember as a 3-word address. However, they are also entirely meaning neutral, easy to pronounce well and based on a standard that is public, universal, and designed for learning and scrutiny.

The problems inherent in the platform become more significant when considering multiple languages. While numbers have a straightforward and direct translation between languages, W3W addresses certainly do not.

Now available in over 50 languages, each one has its own book of addresses for every square. Adding more ways to miss-match addresses and describe a single location, the use of words rather than numbers invites almost as many problems as it solves.

Similarly, an over-reliance on a proprietary platform in any form of public service is rarely a sound technical idea. What3Words is thoroughly locked down with lengthy terms and conditions and a comprehensive privacy policy designed around their business model.

An organisation using more than 10,000 address lookups is subject to a sales agreement that isn’t publicly available or able to be disclosed. If you were looking for a solution less well-suited for the emergency services or public service, then you’d be hard-pressed to find it.

The root of the problem doesn’t lie in any one single app, however. A much wider problem is in users being unfamiliar with navigation at all.

Relying on a smartphone to get you out of trouble in an emergency will always be an idea filled with difficulty and vulnerability.

There’s a delicate and difficult balancing act to be taken in making the hills and wild places as accessible and welcoming as possible while also encouraging visitors to take note of the skills and tools to do so safely.

Learning to navigate with a map and compass is a skill that can be learned in a day and practised in a handful of fair-weather outings. A small investment of time and money; it’s one with a rich pay-off that leaves you less vulnerable to battery drain, app outages, or any other outside influences.

Alternatives to What3Words

Source: OS Locate

Having a means of instantly locating yourself, on or off the hills, is an invaluable resource. Smartphone solutions developed in conjunction with Mountain Rescue can pinpoint your location and give you a way to quickly take a grid reference.

  • Sarloc and Phone Finder are tools developed by mountain rescue team members and used whenever possible to obtain an accurate location.
  • Ordinance Survey produce the app OS Locate, allowing people to locate themselves using GPS latitude, longitude, and altitude even without a mobile signal

Of course, mountain rescue teams are particularly keen to encourage anyone planning a lengthy or difficult day in the outdoors to carry a map and compass and the skills to use them. It’s also encouraged that users register their device for the text 999 service for situations where poor mobile signal or audio issues may make calling for assistance all but practically impossible.

What3Words is a remarkable app and even more remarkable technology solution. It has abundant uses and a strong place in day-to-day life.

The company have been keen to point out that they have aided in numerous rescues and saved lives on and off the hills. However, it’s hard to ignore the glaring issues in practical use, proprietary technology, and poor internationalisation that make it poorly suited to safety-critical scenarios.

Mountain rescue teams are similarly keen to point out that whatever location information is provided will always be converted into a grid reference before crews can take action. Reducing the chances for miscommunication or error, it’s hard to find a compelling reason to move away from such a widely recognised navigation method.

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