> For the complete documentation index, see [llms.txt](https://docs.mapbox.com/mapbox-gl-js/llms.txt)
# Add live realtime data
This example queries an external data feed for the realtime location of the International Space Station (ISS) and displays it on a map. [`setInterval`](https://developer.mozilla.org/en-US/docs/Web/API/setInterval) is used to fetch the latest location every second. The ISS is moving at a speed of 28,000 km/h (17,500 mph), so the location updates often.
The longitude and latitude coordinates are converted to GeoJSON, which is used to update [`GeoJSONSource`](https://docs.mapbox.com/mapbox-gl-js/api/sources/#geojsonsource). A [`symbol`](https://docs.mapbox.com/style-spec/reference/layers/#symbol) layer with a custom icon shows the location of the ISS on the map.
> Example code:
**JavaScript**
```html
Add live realtime data
```
**React**
```jsx
import React, { useEffect, useRef, useState } from 'react';
import * as mapboxgl from 'mapbox-gl/esm';
import 'mapbox-gl/dist/mapbox-gl.css';
const MapboxExample = () => {
const mapContainerRef = useRef();
const mapRef = useRef();
const [data, setData] = useState();
useEffect(() => {
mapRef.current = new mapboxgl.Map({
// TO MAKE THE MAP APPEAR YOU MUST
// ADD YOUR ACCESS TOKEN FROM
// https://account.mapbox.com
accessToken: 'YOUR_MAPBOX_ACCESS_TOKEN',
container: mapContainerRef.current,
style: 'mapbox://styles/mapbox/standard',
zoom: 1.5
});
mapRef.current.on('load', () => {
mapRef.current.loadImage(
'/mapbox-gl-js/assets/iss.png',
async (error, image) => {
if (error) throw error;
// Add the image to the map style.
mapRef.current.addImage('iss', image);
// Get the initial location of the International Space Station (ISS).
const geojson = await getLocation();
// Add the ISS location as a source.
mapRef.current.addSource('iss', {
type: 'geojson',
data: geojson
});
// Add the rocket symbol layer to the mapRef.current.
mapRef.current.addLayer({
id: 'iss',
type: 'symbol',
source: 'iss',
layout: {
'icon-image': 'iss'
}
});
// Update the source from the API every 2 seconds.
const updateSource = setInterval(async () => {
const geojson = await getLocation(updateSource);
mapRef.current.getSource('iss').setData(geojson);
}, 2000);
async function getLocation(updateSource) {
// Make a GET request to the API and return the location of the ISS.
try {
const response = await fetch(
'https://api.wheretheiss.at/v1/satellites/25544',
{ method: 'GET' }
);
const { latitude, longitude } = await response.json();
// Fly the map to the location.
mapRef.current.flyTo({
center: [longitude, latitude],
speed: 0.5
});
// Return the location of the ISS as GeoJSON.
return {
type: 'FeatureCollection',
features: [
{
type: 'Feature',
geometry: {
type: 'Point',
coordinates: [longitude, latitude]
}
}
]
};
} catch (err) {
// If the updateSource interval is defined, clear the interval to stop updating the source.
if (updateSource) clearInterval(updateSource);
throw new Error(err);
}
}
}
);
});
return () => {
mapRef.current.remove();
};
}, []);
useEffect(() => {
if (!data) return;
mapRef.current.getSource('iss').setData(data);
mapRef.current.flyTo({
center: data.features[0].geometry.coordinates,
speed: 0.5
});
}, [data]);
return ;
};
export default MapboxExample;
```