And there is at least one known instance of such system: many car navigation systems in Japan have support for Denso Mapcode [1]. Its algorithm is almost trivia

And there is at least one known instance of such system: many car navigation systems in Japan have support for Denso Mapcode [1]. Its algorithm is almost trivial but has a private mapping which effectively makes its entirty proprietary. [1] https://www.denso-communications.jp/mapcode/ https://www.denso-communications.jp/mapcode/