How to use it
- Press Find me and allow the browser to use your location.
- Read the country in the first card. The map shows its outline, code and time zone.
- To check another place, type it in the box, or click the map, or drag the pin.
- Copy the link in the address bar to share the result.
5 practical uses
- Confirm which side of a border you are on when a road, a trail or a river crossing is the frontier.
- Check the country a photo or a GPS log was taken in from its coordinates.
- Know the local time zone and the country code before a call or a customs form.
- Settle a pub argument on a ferry, a flight or a long-distance train.
- Check where a shipment or a vehicle tracker is reporting from.
The maths behind it
The device gives a latitude and longitude. The page tests the point against every country outline with a point-in-polygon test: a ray from the point crosses the outline an odd number of times when the point is inside. A bounding-box check first rules out most countries. The geocoder does the same on the full-resolution OpenStreetMap boundaries and names the place.
How accurate it is
A phone with GPS is accurate to a few metres outdoors; a laptop on Wi-Fi is often within a hundred metres, and a wired desktop may be placed at the nearest exchange, a town away. Near a boundary, drag the pin to check. The outline comes from Natural Earth (1:50m), which is drawn for a world map and can be a little off at a coast or a land border. Disputed areas follow the mapmaker's convention.
Privacy
The page never stores your position. The link in the address bar carries the coordinates so you can share or bookmark the result; clear it if you would rather not.