The hierarchical geographical domains you are remembering must have been the 2000 '.geo' Top Level Domain (TLD) proposal from SRI. It didn't work out, but I remember thinking at the time that it was a cool idea.

It would have provided geographical information based on a domain encoded grid, not for human but machine consumption (e.g. acme.2e5n.10e30n.geo).

https://en.wikipedia.org/wiki/.geo

In a similar vein there is the 'e164.arpa' domain for mapping telephone numbers.

https://en.wikipedia.org/wiki/Telephone_number_mapping