KEYPAD 1–9 Open location code · spec v4

Every place on Earth,
named from its nearest airport.

No word lists. No random letters. An AirportVector code tells you which airport, which direction and how far — before you even open a map.

Try the live map Read a code in 10 seconds

DEPARTURESLOCATION CODE--:--

5.5 km north-west of Tiruchirappalli International Airport

Near Trichy Central Bus Stand, India

01 Live map

Click anywhere — land, sea, even Antarctica. Or paste a code. Everything runs in your browser; nothing is sent to a server.

Click the map to get a code

Location code

Pick a spot on the map to see its code.

Every place on Earth, named from its nearest airport. Tap the map or use My location. What is this?

Your location and saved places stay on this device. Nothing is uploaded.

Try these

02 Read a code in 10 seconds

A code is an airport and ten digits, read like a phone number. That's all.

TRZ 55511 79566

TRZ The nearest airport — Tiruchirappalli, India.
55511 The 1 km square. Three 5s in front: within 4.5 km of the airport, then north-west.
79566 The exact spot inside that square, down to about 4 m.

Say it like a phone number: T-R-Z, five-five-five-one-one, seven-nine-five-six-six.

Every digit is a key on a phone keypad

1NW2N3NE 4W5AIRPORT6E 7SW8S9SE

The area round the airport is split into 9 squares, numbered like a keypad. Each square is split into 9 again, and again: 81 km → 27 km → 9 km → 3 km → 1 km.

5 is always the middle, so it always holds the airport. Count the 5s at the start to know how close a place is:

TRZ 5····within 40 km
TRZ 55···within 13.5 km
TRZ 555··within 4.5 km
TRZ 5555·within 1.5 km

Far from any airport? The first group just gets longer — 6 digits past 121 km, more in the deep ocean.

Shorter code, bigger square

TRZ 555111 km
TRZ 55511 79111 m
TRZ 55511 79537 m
TRZ 55511 795664 m

A short code is the start of the long one — trimming digits just zooms out. Places that share a start share a square.

03 No gaps. Anywhere.

4,133 commercial airports anchor the whole planet. The farthest any point gets from its nearest airport is about 5,150 km — deep in Antarctica.

World map coloured by the length of the code's first group: green within 121 km of an airport (5 digits), yellow 121 to 364 km (6 digits), orange farther (7 or more digits, mostly ocean and Antarctica). — 5 digits · 22% of the globe, 58% of land 6 digits · 24% / 38% 7+ digits · 54% / 4%

Human context

“NW of Trichy airport, 5 km” means something to a person. A string of random letters or three random words doesn't tell you where on Earth to start.

Exact distances

The grid is azimuthal-equidistant on the WGS84 ellipsoid, so √(X² + Y²) is the true ground distance to the airport.

Open & offline

A small anchor file and plain maths. No lookups, no accounts, no network — the demo above runs entirely in your browser.

04 Developers

Reference implementations in Python and JavaScript, tested against each other on 120,000+ checks.

Pythonairportvector.py

import airportvector as av

av.encode(10.7950461, 78.6793020)
# 'TRZ-55511-79566'
av.describe("TRZ 55511 79566")
# '5.5 km NW of TRZ (Tiruchirappalli International Airport)'
av.decode("TRZ 55511 79566")
# (10.795057, 78.679284)

JavaScriptoavg.js

OAVG.loadRegistry(await (await fetch("/anchors.json")).json());

OAVG.encode(51.5074, -0.1278);         // "LCY-55444-38173"
OAVG.display("LCY-55444-38173");       // "LCY 55444 38173"
OAVG.neighbors("TRZ-55511");           // the 8 squares around it
OAVG.shorten("TRZ-55511-79566", "1km"); // "TRZ-55511"

GitHub repository ↗ Specification v4 ↗ Download oavg.js Download anchors.json