Rio de Janeiro

Brazil

With a code: #9GFJN-P580G
Said aloud: Rio de Janeiro P580G

What the code says

The Grid Point Code for Rio de Janeiro is #9GFJN-P580G. It names a cell 2.56 m north to south and 3.15 m east to west, centred on 22°54'23.13"S, 43°10'56.02"W, and it turns back into that cell on any phone or computer by arithmetic alone: no network, no account, no lookup table.

The point used is the one GeoNames records for Rio de Janeiro, near its centre.

Code: #9GFJN-P580G
With a check character: #9GFJN-P580G*D
Short form: P580G
Cell centre: -22.906426, -43.182228
Cell size: 2.56 m by 3.15 m
Country: Brazil
Population: 6,747,815

How to give this address

On a sign, a form or a delivery note: The whole code, #9GFJN-P580G. It needs nothing else: no city, no street, no network to read it back.
Said aloud, in Brazil: Rio de Janeiro P580G: a name both people know, then the last five characters. They give back the exact code for anywhere within 4.0 km north or south and 4.9 km east or west of Rio de Janeiro. Further away the same five name somewhere else, which is why the whole code is what goes on a sign.
Copied by hand, or read over a phone: #9GFJN-P580G*D. The character on the end catches any single mistyped symbol and any two neighbours swapped.
As a link or a square code: Open it on the map, move to the exact door, and add directions if the code needs help: "blue gate, second floor". The link and the square code carry them. Nothing is kept on this site.

From the city to the door

The first four characters name a cell about 40 km by 49.2 km here. Each one after that picks one of 25 inside the last, so the whole ten name a spot about the size of a doorway.

9GFJMetropolitan area40 km by 49.2 km
9GFJNDistrict8 km by 9.84 km
9GFJNPSuburb1.6 km by 1.97 km
9GFJNP5A few streets320 m by 394 m
9GFJNP58Building64 m by 78.8 m
9GFJNP580Entrance12.8 m by 15.8 m
9GFJNP580GDoorway2.56 m by 3.15 m

More in Brazil

City, region and population from GeoNames, under CC BY 4.0.