# Arc Layer

This example shows how to use the [ArcLayer](https://deck.gl/docs/api-reference/layers/arc-layer) to **render raised arcs** joining pairs of source and target points.

{% tabs %}
{% tab title="CARTO 3" %}
{% embed url="<https://codesandbox.io/embed/carto-google-maps-examples-w2puou?fontsize=14&hidenavigation=1&initialpath=%2Fadvanced-examples%2Farc-layer.html&module=%2Fadvanced-examples%2Farc-layer.html>" %}

```html
<!DOCTYPE html>
<html>
  <head>
    <title>Arc Layer</title>
    <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>
    <script src="https://unpkg.com/deck.gl@^8.8.0/dist.min.js"></script>
    <script src="https://unpkg.com/@deck.gl/carto@^8.8.0/dist.min.js"></script>
    <style>
      #map {
        height: 100%;
      }

      html,
      body {
        height: 100%;
        margin: 0;
        padding: 0;
      }
    </style>
  </head>

  <body>
    
    <div id="map"></div>

    <script  
      src="https://maps.googleapis.com/maps/api/js?key=AIzaSyDvHtBZM79O5uGTBT1ZOWOKW2_FVMstHNs&callback=initMap&libraries=&v=beta"
      async
    ></script>

  </body>

  <script type="text/javascript">
    let map;

    function initMap() {
      map = new google.maps.Map(document.getElementById("map"), {
        center: { lat: 30, lng: 10 },
        zoom: 2,
        tilt: 30,
        mapId: '74fb72d0338f9316',
        fullscreenControl: false,
        streetViewControl: false,
        zoomControlOptions: {
          position: google.maps.ControlPosition.LEFT_BOTTOM,
        },
      });

      deck.carto.setDefaultCredentials({
        apiBaseUrl: 'https://gcp-us-east1.api.carto.com',
        accessToken: 'eyJhbGciOiJIUzI1NiJ9.eyJhIjoiYWNfbHFlM3p3Z3UiLCJqdGkiOiI1YjI0OWE2ZCJ9.Y7zB30NJFzq5fPv8W5nkoH5lPXFWQP0uywDtqUg8y8c'
      });

      // Fetch Data from CARTO
      const geojsonData = deck.carto.fetchLayerData({
          type: deck.carto.MAP_TYPES.QUERY,
          source: `SELECT geom, scalerank FROM cartobq.public_account.airports_to_london WHERE scalerank > 7`,
          connection: 'bqconn',
          format: deck.carto.FORMATS.GEOJSON
      });

      const deckOverlay = new deck.GoogleMapsOverlay({
        layers: [
          new deck.ArcLayer({
            id: 'arc-layer',
            data: geojsonData.then(({ data }) => data.features),
            getSourcePosition: f => [-0.4531566, 51.4709959], // London
            getTargetPosition: f => f.geometry.coordinates,
            getSourceColor: [0, 128, 200],
            getTargetColor: [200, 0, 80],
            getWidth: 1
          })
        ]
      });

      deckOverlay.setMap(map);
    }

  </script>
</html>
```

{% endtab %}

{% tab title="CARTO 2" %}
{% embed url="<https://codesandbox.io/embed/carto-google-maps-examples-w2puou?fontsize=14&hidenavigation=1&initialpath=%2Fadvanced-examples%2farc-layer-carto2.html&module=%2Fadvanced-examples%2farc-layer-carto2.html>" %}

```html
<!DOCTYPE html>
<html>
  <head>
    <title>Arc Layer</title>
    <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>
    <script src="https://unpkg.com/deck.gl@^8.8.0/dist.min.js"></script>
    <script src="https://unpkg.com/@deck.gl/carto@^8.8.0/dist.min.js"></script>
    <style>
      #map {
        height: 100%;
      }

      html,
      body {
        height: 100%;
        margin: 0;
        padding: 0;
      }
    </style>
  </head>

  <body>
    
    <div id="map"></div>

    <script  
      src="https://maps.googleapis.com/maps/api/js?key=AIzaSyDvHtBZM79O5uGTBT1ZOWOKW2_FVMstHNs&callback=initMap&libraries=&v=beta"
      async
    ></script>

  </body>

  <script type="text/javascript">
    let map;

    function initMap() {
      map = new google.maps.Map(document.getElementById("map"), {
        center: { lat: 30, lng: 10 },
        zoom: 2,
        tilt: 30,
        mapId: '74fb72d0338f9316',
        fullscreenControl: false,
        streetViewControl: false,
        zoomControlOptions: {
          position: google.maps.ControlPosition.LEFT_BOTTOM,
        },
      });

      deck.carto.setDefaultCredentials({
        username: 'public',
        apiKey: 'default_public',
        apiVersion: deck.carto.API_VERSIONS.V2,
      });

      // Fetch Data from CARTO
      // Notice that you can use any Deck.gl layer with CARTO datasets getting GeoJSON data from CARTO's API.
      const fetchData = () => {
        const url = 'https://public.carto.com/api/v2/sql?q=SELECT the_geom, scalerank FROM airports_to_london WHERE scalerank > 7&format=geojson';
        return(fetch(url).then(response => response.json()));
      }

      const deckOverlay = new deck.GoogleMapsOverlay({
        layers: [
          new deck.ArcLayer({
            id: 'arc-layer',
            data: fetchData().then(geojsonData => geojsonData.features),
            getSourcePosition: f => [-0.4531566, 51.4709959], // London
            getTargetPosition: f => f.geometry.coordinates,
            getSourceColor: [0, 128, 200],
            getTargetColor: [200, 0, 80],
            getWidth: 1
          })
        ]
      });

      deckOverlay.setMap(map);
    }

  </script>
</html>
```

{% endtab %}
{% endtabs %}


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.carto.com/carto-for-developers/key-concepts/carto-for-deck.gl/basemaps/carto-google-maps/readme-1/advanced-examples/arc-layer.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.
