> For the complete documentation index, see [llms.txt](https://docs.mapbox.com/mapbox-gl-js/llms.txt)
# Add a line to a map using a GeoJSON source
Add a GeoJSON `LineString` to a map using [`addSource`](https://docs.mapbox.com/mapbox-gl-js/api/map/#map#addsource), then style it using [`addLayer`](https://docs.mapbox.com/mapbox-gl-js/api/map/#map#addlayer)'s [`paint`](https://docs.mapbox.com/style-spec/reference/layers/#line) properties.
> **Related content (related): [Learn more about GeoJSON](null)**
>
> GeoJSON is a format for encoding geographic data structures and includes support for different geometry types including points, linestrings, polygons and more.
> Example code:
**JavaScript**
```html
Add a line to a map using a GeoJSON source
```
**React**
```jsx
import React, { useEffect, useRef } from 'react';
import * as mapboxgl from 'mapbox-gl/esm';
import 'mapbox-gl/dist/mapbox-gl.css';
const MapboxExample = () => {
const mapContainerRef = useRef(null);
const mapRef = useRef(null);
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',
center: [-122.486052, 37.830348],
zoom: 14
});
mapRef.current.on('load', () => {
mapRef.current.addSource('route', {
type: 'geojson',
data: {
type: 'Feature',
properties: {},
geometry: {
type: 'LineString',
coordinates: [
[-122.483696, 37.833818],
[-122.483482, 37.833174],
[-122.483396, 37.8327],
[-122.483568, 37.832056],
[-122.48404, 37.831141],
[-122.48404, 37.830497],
[-122.483482, 37.82992],
[-122.483568, 37.829548],
[-122.48507, 37.829446],
[-122.4861, 37.828802],
[-122.486958, 37.82931],
[-122.487001, 37.830802],
[-122.487516, 37.831683],
[-122.488031, 37.832158],
[-122.488889, 37.832971],
[-122.489876, 37.832632],
[-122.490434, 37.832937],
[-122.49125, 37.832429],
[-122.491636, 37.832564],
[-122.492237, 37.833378],
[-122.493782, 37.833683]
]
}
}
});
mapRef.current.addLayer({
id: 'route',
type: 'line',
source: 'route',
layout: {
'line-join': 'round',
'line-cap': 'round'
},
paint: {
'line-color': '#888',
'line-width': 8
}
});
});
});
return (
);
};
export default MapboxExample;
```