Comment by adambyrtek | Hacker News Reader

Comment by adambyrtek | Hacker News Reader

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I inherited a property management system where previous developers used what3words for storing location of homes (since reverse geocoding based on address is not reliable in some countries we support).

However, after an internal review we realised that a lot of our UK properties have locations in Asia or the US... It turned out that typos in what3words often result in a valid location on the other side of the world. The most common mistakes we found were plural words instead of singular ones (e.g. "cats" not "cat") or the other way around.

Of course we could have improved the user interface or added some extra validations, but at this point we realised that what3words is more trouble than it's worth, and decided to migrate to storing lat/long directly. That allowed us to avoid a third-party dependency and simplify the code, since we had to cache lat/long anyway in order to plot properties on a map or calculate distances between them.

The behaviour you're describing is actually supposed to be a feature. They call it "Error detection" on https://what3words.com/about, which apparently it's not.

I imagine that a single digit typo in latitude could also result in a valid location on the other side of the world

Sure, but none of the numbers are homophones or even particularly easy to confuse (in English, anyway) when giving a location verbally. W3W marketing claims none of their words are either, but the evidence suggests otherwise...

Latitude errors are also much easier to correct if you incorrectly memorise it but know other information (country/city). But if you find out that arbitrary.word.cat gives you an obviously incorrect location, you've got very little chance of realising that actually it must have been arbitrary.world.cats

This is true, but the structure of the number itself carries a connotation to the reader to pay extra attention to their accuracy.

We expect numbers to be number-like where every little digit is important. We expect words to be word-like where plurals and sometimes even synonyms mean the same or similar things.

But bounds checking is a lot simpler.

...in which we learn that the previous developers hated everyone.

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