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Why wouldn't they use 36 (Letters+digits) to break it down in a 6x6 area instead? Much more precise at the same length. At 6 length, you're already down to the
by bufferoverflow 8y ago
Why wouldn't they use 36 (Letters+digits) to break it down in a 6x6 area instead? Much more precise at the same length.
At 6 length, you're already down to the kilometer precision at the equator. At 9 length you're down to 4 meters.
And that's with a dumb grid division, which is very uneven on the globe, the cube projection is probably a better way to deal with it.
- tonyg 8y agoThe larger the alphabet, the larger the risk of glyph confusion. Here's the alphabet they chose: // The character set used to encode the values. var CODE_ALPHABET_ = '23456789CFGHJMPQRVWX'; It omits easily-confused glyphs like "0oOD", "1lLI" etc.
- awirth 8y agoThis is an interesting alphabet, even Base58 (Bitcoin addresses) have "o" and "1". There's some information on how they generated it here in the spec[1]. The characters that are used in Open Location Codes were chosen by computing all possible 20 character combinations from 0-9A-Z and scoring them on how well they spell 10,000 words from over 30 languages. This was to avoid, as far as possible, Open Location Codes being generated that included recognisable words. The selected 20 character set is made up of "23456789CFGHJMPQRVWX". [1]: https://github.com/google/open-location-code/blob/master/docs/olc_definition.adoc#open-location-code https://github.com/google/open-location-code/blob/master/doc...
- richthegeek 8y agohttps://github.com/google/open-location-code/wiki/Evaluation-of-Location-Encoding-Systems https://github.com/google/open-location-code/wiki/Evaluation... One of the design decisions was to avoid ambiguous characters, so that cuts out at least 9 (I1L 0OB8).
- kiriakasis 8y agoOthers have noted ambiguous character, but an equally important factor was to avoid swear words in all the languages that use the Latin alphabet (or have a latinized form like Russian, Chinese and others) It is almost impossible to make words out of the allowed characters