Word-Based Location Systems Explained

A word-based location system replaces coordinates with a short combination of ordinary words. The world is divided into a very large number of small cells, and each cell is assigned a unique word sequence. Instead of saying 51.50073, -0.12463, you would give a set of three words that stand for the same small square.

The idea

Numbers are accurate but hard to remember, easy to mistype and awkward to say aloud. Words are the opposite: people recall them well, spell them reasonably, and can read them over the phone. A word-based system tries to combine the precision of coordinates with the convenience of language.

How it is typically built

1. Divide the world into cells of a fixed size, so every point falls into exactly one cell.
2. Number the cells. There can be tens of trillions of them at a few metres' size.
3. Map each number to a word combination using a word list and a fixed algorithm. Three words from a list of about 40,000 entries give roughly 64 trillion combinations, which is enough to cover the globe at a few metres per cell.

The mapping is deterministic, so the same words always return the same cell.

Benefits

• Memorable and speakable: useful for informing a driver, a friend or an emergency service.
• Language-friendly in principle: different word lists can be used for different languages.
• Accessible to people who struggle with long number strings.

Trade-offs

• Different languages give different words, so a code in one language is not recognisable in another unless a translation is provided.
• Close words do not mean close places. Changing a single word can move the location to the other side of the world, while a numeric code typically keeps nearby places similar.
• Error detection: a mistyped or misheard word can still be a valid combination that points somewhere else.
• Proprietary mappings: some systems keep their word lists or algorithms closed, which affects reuse and long-term dependency.

Words, numbers and letters

Not every compact code uses dictionary words. Some use letters and digits, such as Plus Codes and geohash, because these formats are language-neutral and can show nearness through shared prefixes. UPCS uses a country prefix and two short blocks of letters and digits, for example PK-1A2B-3C4D, so that a code can be typed on any keyboard and checked quickly.

Choosing the right approach

The right system depends on who will use it and where. Think about languages, how the code will be communicated, whether it must be open or can be proprietary, and whether it should hint at the general area. For how any of these codes come from coordinates, read how location codes are generated from coordinates.