Locate the User's Position

The HTML Geolocation API is used to get the geographical position of a user.

Since this can compromise privacy, the position is not available unless the user approves it.

Note: Geolocation is most accurate for devices with GPS, like smartphone.


Using the Geolocation API

The getCurrentPosition() method is used to return the user's position.

The example below returns the latitude and longitude of the user's position:

EXAMPLE ❯


Handling Errors and Rejections

The second parameter of the getCurrentPosition() method is used to handle errors. It specifies a function to run if it fails to get the user's location:

EXAMPLE ❯


Displaying the Result in a Map

To display the result in a map, you need access to a map service, like Google Maps.

In the example below, the returned latitude and longitude is used to show the location in a Google Map (using a static image):

Example:

function showPosition(position) {
  let latlon = position.coords.latitude + "," + position.coords.longitude;

  let img_url = "https://maps.googleapis.com/maps/api/staticmap?center=
  "
+latlon+"&zoom=14&size=400x300&sensor=false&key=YOUR_KEY";

  document.getElementById("mapholder").innerHTML = "<img src='"+img_url+"'>";
}


Location-specific Information

This page has demonstrated how to show a user's position on a map.

Geolocation is also very useful for location-specific information, like:

Up-to-date local information

Showing Points-of-interest near the user

Turn-by-turn navigation (GPS)


The getCurrentPosition() Method - Return Data

The getCurrentPosition() method returns an object on success. The latitude, longitude and accuracy properties are always returned. The other properties are returned if available:

Property Returns
coords.latitude The latitude as a decimal number (always returned)
coords.longitude The longitude as a decimal number (always returned)
coords.accuracy The accuracy of position (always returned)
coords.altitude The altitude in meters above the mean sea level (returned if available)
coords.altitudeAccuracy The altitude accuracy of position (returned if available)
coords.heading The heading as degrees clockwise from North (returned if available)
coords.speed The speed in meters per second (returned if available)
timestamp The date/time of the response (returned if available)


Geolocation Object - Other interesting Methods

The Geolocation object also has other interesting methods:

watchPosition() - Returns the current position of the user and continues to return updated position as the user moves (like the GPS in a car).

clearWatch() - Stops the watchPosition() method.

The example below shows the watchPosition() method. You need an accurate GPS device to test this (like smartphone):

EXAMPLE ❯