A geo: URI, defined in RFC 5870, is a uniform way to identify a physical location by its coordinates. Many phones treat a geo: link as a request to open a map at that point, so it works as a location share or a clickable map pin.

What order are the coordinates in?

The format is geo:latitude,longitude with an optional third value for altitude in metres. Latitude comes first, then longitude, separated by commas — the opposite order from how many web map APIs accept query strings.

What does the u parameter mean?

The u parameter is the uncertainty, an accuracy radius in metres around the point. geo:48.2,16.3;u=25 means the true position is within roughly 25 metres of the stated coordinates. Omit it when the position is exact.

How precise should the numbers be?

Decimal degrees with six places resolve to about 0.1 metres, which is more than enough for any practical location. The encoder keeps the digits you enter and validates that latitude is within plus or minus ninety and longitude within plus or minus one hundred eighty degrees.

Is my location uploaded?

No. The geo: URI is built entirely in your browser, so your coordinates are never sent to a server.

Geo URI Encoder — Gera Tools

The geo: URI encoder turns latitude, longitude and an optional altitude into a valid RFC 5870 geo: URI — the standard, app-neutral way to point at a physical location. Many mobile platforms open a map when a geo: link is tapped, so it doubles as a share link or QR-code map pin.

How it works

RFC 5870 defines the syntax geo:lat,lon[,alt][;crs=...][;u=...]. Latitude (-90 to 90) comes first, then longitude (-180 to 180), both in decimal degrees on the WGS-84 coordinate reference system that is the default. An optional third comma-separated value is the altitude in metres. The u parameter records positional uncertainty as a radius in metres.

The encoder validates that the two angles are real numbers in range, then assembles the components. Because numeric coordinates and standard parameters need no escaping, the output is the plain geo: string. Altitude and u are appended only when supplied.

Example

Lat 48.2010, Lon 16.3695, alt 183, u 25
-> geo:48.201,16.3695,183;u=25

A coordinate at the equator and prime meridian is simply geo:0,0.

Notes

Remember the order is latitude-then-longitude, which is the reverse of some web map query strings — getting it backwards drops the pin in the wrong hemisphere. WGS-84 is assumed, so you rarely need a crs parameter. The output fits directly in an <a href="geo:..."> link. Everything runs locally; your coordinates are never uploaded.