Porto

What the code says

The Grid Point Code for Porto is #HXD2N-DF7MX. It names a cell 2.56 m north to south and 2.58 m east to west, centred on 41°08'54.63"N, 8°36'39.55"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 Porto, near its centre.

Code

#HXD2N-DF7MX

With a check character

#HXD2N-DF7MX*K

Short form

DF7MX

Cell centre

41.148507, -8.610985

Cell size

2.56 m by 2.58 m

Country

Portugal

Population

252,687

How to give this address

On a sign, a form or a delivery note

The whole code, #HXD2N-DF7MX. It needs nothing else: no city, no street, no network to read it back.

Said aloud, in Portugal

Porto DF7MX: 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 4.0 km east or west of Porto. 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

#HXD2N-DF7MX*K. 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 40.2 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.

1. 2HXD2Metropolitan area40 km by 40.2 km
2. NHXD2NDistrict8 km by 8.05 km
3. DHXD2NDSuburb1.6 km by 1.61 km
4. FHXD2NDFA few streets320 m by 322 m
5. 7HXD2NDF7Building64 m by 64.4 m
6. MHXD2NDF7MEntrance12.8 m by 12.9 m
7. XHXD2NDF7MXDoorway2.56 m by 2.58 m

More in Portugal

• Feira da Ladra
• Lisbon
• Ponta da Piedade
• Mount Pico