Grid Point Code

Play

Chongming

China

With a code
#L9HDT-38MK5
Said aloud
Chongming 38MK5

Get the code for your door

What the code says

The Grid Point Code for Chongming is #L9HDT-38MK5. It names a cell 2.56 m north to south and 2.91 m east to west, centred on 31°37'06.66"N, 121°41'46.39"E, 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 Chongming, near its centre.

Code
#L9HDT-38MK5
With a check character
#L9HDT-38MK5*8
Short form
38MK5
Cell centre
31.618518, 121.696220
Cell size
2.56 m by 2.91 m
Country
China
Population
637,921

How to give this address

On a sign, a form or a delivery note

The whole code, #L9HDT-38MK5. It needs nothing else: no city, no street, no network to read it back.

Said aloud, in China

Chongming 38MK5: 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 4.6 km east or west of Chongming. 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

#L9HDT-38MK5*8. 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 45.5 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. L9HDMetropolitan area40 km by 45.5 km
  2. L9HDTDistrict8 km by 9.1 km
  3. L9HDT3Suburb1.6 km by 1.82 km
  4. L9HDT38A few streets320 m by 364 m
  5. L9HDT38MBuilding64 m by 72.8 m
  6. L9HDT38MKEntrance12.8 m by 14.6 m
  7. L9HDT38MK5Doorway2.56 m by 2.91 m

More in China

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