San Juan

What the code says

The Grid Point Code for San Juan is #GHTLK-DJ09R. It names a cell 2.56 m north to south and 3.24 m east to west, centred on 18°27'58.83"N, 66°06'20.55"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 San Juan, near its centre, and San Juan is the capital of Puerto Rico.

Code

#GHTLK-DJ09R

With a check character

#GHTLK-DJ09R*3

Short form

DJ09R

Cell centre

18.466341, -66.105708

Cell size

2.56 m by 3.24 m

Country

Puerto Rico

Population

418,140

How to give this address

On a sign, a form or a delivery note

The whole code, #GHTLK-DJ09R. It needs nothing else: no city, no street, no network to read it back.

Said aloud, in Puerto Rico

San Juan DJ09R: 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 5.1 km east or west of San Juan. 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

#GHTLK-DJ09R*3. 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 50.7 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.

1. LGHTLMetropolitan area40 km by 50.7 km
2. KGHTLKDistrict8 km by 10.1 km
3. DGHTLKDSuburb1.6 km by 2.03 km
4. JGHTLKDJA few streets320 m by 405 m
5. 0GHTLKDJ0Building64 m by 81.1 m
6. 9GHTLKDJ09Entrance12.8 m by 16.2 m
7. RGHTLKDJ09RDoorway2.56 m by 3.24 m

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