getCurrentPositionAsync
- React Native course
- Advanced
- Lesson 21/83
- 5 min
Learn the current location with getCurrentPositionAsync.
getCurrentPositionAsync
To get the current location once you call Location.getCurrentPositionAsync. The function returns an object; the coords field carries the location info. coords.latitude is the latitude and coords.longitude is the longitude value.
The function takes an options object; for example { accuracy: Location.Accuracy.High } requests high accuracy. With high accuracy the location is more precise but slower to arrive. Example: const loc = await Location.getCurrentPositionAsync({ accuracy: Location.Accuracy.High }). The result is read with loc.coords.latitude and loc.coords.longitude.
The coords field
The coords field of the location object is the most important part. coords.latitude carries the latitude value (for example 41.0082) and coords.longitude carries the longitude value (for example 28.9784). Together these two values define a point; it can be shown on a map.
coords also carries extra info like altitude (height), accuracy (accuracy radius), speed (speed). The most used are latitude and longitude. You write these values to state and show them as a marker on the map. Since the values are decimals they are processed as numbers.
Practice Get the current location
Complete the getLocation function. Call const loc = await Location.getCurrentPositionAsync({ accuracy: Location.Accuracy.High }). Return an object with return { latitude: loc.coords.latitude, longitude: loc.coords.longitude }.
Starter code
import * as Location from 'expo-location';
export async function getLocation() {
// get the current location and return lat/lng
}Sample solution
const loc = await Location.getCurrentPositionAsync({
accuracy: Location.Accuracy.High,
});
return { latitude: loc.coords.latitude, longitude: loc.coords.longitude };Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Write the location variable
const ____ = await Location.getCurrentPositionAsync({ accuracy: Location.Accuracy.High });const loc = await Location.getCurrentPositionAsync({ accuracy: Location.Accuracy.High });Explanation: The loc variable carries the location object.
2 What does coords.latitude carry?
const lat = loc.???- lat
- coords.latitude Correct answer
- lng
- latitude
Explanation: coords.latitude carries the latitude value.
3 Match each field to its meaning
| Term | Meaning |
|---|---|
coords |
Location object |
latitude |
Latitude |
longitude |
Longitude |
accuracy |
Accuracy |