4 ms·

Will two close-by locations eg. just a meter apart have any part of the phrase in common?

• thelittlenag 7y ago
  A five word phrase is roughly a 5m x 5m region, so 1m wouldn't be enough to move into the next block. But in general yes, locations that are "close by" will share the same set of words. The mapping itself is extremely simple. A geohash is encoded as string of alphanumeric characters where each character is in base-32. This means each character encodes 5-bits of coordinate information. To get to a 5m x 5m region you need 45-bits worth or 9 geohash characters. To map this 9 character geohash to a phrase is simple - we simply use the binary representation of the characters as a numeric index into a fixed dictionary of words. The first character is mapped to a word in a dictionary containing 32 entries. After that we map characters in pairs to dictionaries of 1024 words; 2 geohash characters being 5-bits we get a 10-bit index. So two geohashes that share the same prefix will also share the same words, modulo our grouping scheme.