---
title: "How to create a countries map with your own data | JavaScript maps SDK"
description: "Join custom data with MapTiler Countries for choropleth maps."
---

> For AI agents: a documentation index is available at [/llms.txt](https://docs.maptiler.com/llms.txt). Markdown versions of all pages are available by appending .md to any URL.

# How to create a countries map with your own data

This tutorial demonstrates the process of merging your own personalized data with the [MapTiler Countries](https://www.maptiler.com/countries/) dataset, allowing you to create a [choropleth map](../choropleth-geojson/). The MapTiler Countries dataset primarily consists of information regarding the administrative divisions of countries and their territories around the world.

For this specific example, we will be creating a choropleth map that showcases the population of some European countries.

## NPM module setup

1.  Install the npm package.
    
    ```bash
    npm install --save @maptiler/sdk
    ```
    
2.  Include the CSS file.
    
    If you have a bundler that can handle CSS, you can `import` the CSS
    
    ```js
    import "@maptiler/sdk/dist/maptiler-sdk.css";
    ```
    
    or include it with a `<link />` in the head of the document via the CDN
    
    ```html
    <link href='https://cdn.maptiler.com/maptiler-sdk-js/v4.2.0/maptiler-sdk.css' rel='stylesheet' />
    ```
    
3.  Include the following code in your JavaScript file (Example: app.js).
    
    ```js
    import * as maptilersdk from '@maptiler/sdk';
    
     maptilersdk.config.apiKey = 'YOUR_MAPTILER_API_KEY_HERE';
     const map = new maptilersdk.Map({
       container: 'map', // container's id or the HTML element to render the map
       style: maptilersdk.MapStyle.DATAVIZ.LIGHT,
          
       center: [13.39, 52.51], // starting position [lng, lat]
       zoom: 2, // starting zoom
          
     });
    ```
    
4.  Replace `YOUR_MAPTILER_API_KEY_HERE` with [your own API key](https://cloud.maptiler.com/account/keys/). Make sure to [secure the key](https://docs.maptiler.com/guides/credentials/api-key/#secure-key) before you publish it.
    
5.  The next is up to you. You can center your map wherever you desire (modifying the `starting position`) and set an appropriate zoom level (modifying the `starting zoom`) to match your users’ needs. Additionally, you can change the map’s look (by updating the `source URL`); choose from a range of visually appealing map styles from our extensive [MapTiler standard maps](https://cloud.maptiler.com/maps/), or create your own to truly differentiate your application.
    
6.  Add event handler for map `load` event. You will add code to create a vector source and a vector layer in this handler.
    
    ```js
    map.on('load', function() {
    
     });
    ```
    
7.  Create vector source. The following snippet creates vector source for the MapTiler Countries dataset.
    
    ```js
    map.on('load', function() {
       map.addSource('statesData', {
         type: 'vector',
         url: `https://api.maptiler.com/tiles/countries/tiles.json`
       });
     });
    ```
    
8.  Get the id of the first symbol layer. We want to include the vector layer below the map labels. That means we need to know the id of the first symbol layer so we can include the vector layer before this layer.
    
    ```js
    // Find the id of the first symbol layer in the map style
     const layers = map.getStyle().layers;
     const firstSymbolId = layers.find(layer => layer.type === 'symbol').id;
    ```
    
9.  Add the vector layer. We need to include `firsSymbolId` to the `map.addLayer` function to display the vector under the maps labels
    
    ```js
    map.addLayer(
       {
         'id': 'countries',
         'source': 'statesData',
         'source-layer': 'administrative',
         'type': 'fill',
         'paint': {
             'fill-color': '#6B7C93',
             'fill-opacity': 1,
             'fill-outline-color': '#000'
         }
       },
       firstSymbolId   
     );
    ```
    
10.  Filter the data to only show the countries. Add a filter to the layer to only display level 0 items.
     
     ```js
     map.addLayer(
        {
          'id': 'countries',
          'source': 'statesData',
          'source-layer': 'administrative',
          'type': 'fill',
          'filter': ['==', 'level', 0],
          'paint': {
              'fill-color': '#6B7C93',
              'fill-opacity': 1,
              'fill-outline-color': '#000'
          }
        },
        firstSymbolId   
      );
     ```
     
11.  Prepare your data. Each feature in the dataset has its own identification for pairing. You need to mark your data with the same identifiers as is stored by features. We will use the iso\_n3 identifier for countries. Alternatively, you can use one of the properties: name, country codes (ISO A2), or wiki data-id. Check out the [Countries dataset schema](https://docs.maptiler.com/schema/countries/#administrative) to see the available fields.
     
     ```js
     const vizData = {
        "8":{"name":"Albania","population":2829741},
        "40":{"name":"Austria","population":8932664},
        "56":{"name":"Belgium","population":11566041},
        "100":{"name":"Bulgaria","population":6916548},
        "191":{"name":"Croatia","population":4036355},
        "196":{"name":"Cyprus","population":896005},
        "203":{"name":"Czechia","population":10701777},
        "208":{"name":"Denmark","population":5840045},
        "233":{"name":"Estonia","population":1330068},
        "246":{"name":"Finland","population":5533793},
        "250":{"name":"France","population":67439599},
        "276":{"name":"Germany","population":83155031},
        "300":{"name":"Greece","population":10682547},
        "348":{"name":"Hungary","population":9730772},
        "352":{"name":"Iceland","population":368792},
        "372":{"name":"Ireland","population":5006907},
        "380":{"name":"Italy","population":59257566},
        "428":{"name":"Latvia","population":1893223},
        "438":{"name":"Liechtenstein","population":39055},
        "440":{"name":"Lithuania","population":2795680},
        "442":{"name":"Luxembourg","population":634730},
        "470":{"name":"Malta","population":516100},
        "499":{"name":"Montenegro","population":620739},
        "528":{"name":"Netherlands","population":17475415},
        "578":{"name":"Norway","population":5391369},
        "616":{"name":"Poland","population":37840001},
        "620":{"name":"Portugal","population":10298252},
        "642":{"name":"Romania","population":19186201},
        "688":{"name":"Serbia","population":6871547},
        "703":{"name":"Slovakia","population":5459781},
        "705":{"name":"Slovenia","population":2108977},
        "724":{"name":"Spain","population":47394223},
        "752":{"name":"Sweden","population":10379295},
        "756":{"name":"Switzerland","population":8667088},
        "792":{"name":"Turkey","population":83614362},
        "807":{"name":"North Macedonia","population":2068808}
      };
     ```
     
12.  Join the data to coresponding features. Use `querySourceFeatures` to get all features from the layer for visualization. We are also filtering for all countries with `['==', 'level', 0]` using style expressions. The second part of the following code goes throw these features and adds attributes from our data array (vizData) to relevant features.
     
     ```js
     function setStates() {
        const countries = map.querySourceFeatures('statesData', {
          sourceLayer: 'administrative',
          filter: ['all', ['==', 'level', 0]],
        });
        countries.forEach(country => {
          if(country.id && vizData[country.id]) {
            map.setFeatureState({
              source: 'statesData',
              sourceLayer: 'administrative',
              id: country.id
            }, {
              population: vizData[country.id].population
            });
          }
        });
        if (countries.length !== 0) {
          map.off('data', afterLoad);
        }
      }
     ```
     
13.  Create a function that validates that the country dataset is loaded to call the `setStates` function.
     
     ```js
     function afterLoad() {
        if (map.getSource('statesData') && map.isSourceLoaded('statesData')) {
          setStates();
        }
      }
     ```
     
14.  Add event handler for map `data` event. Call the `afterLoad` function
     
     ```js
     map.on('data', afterLoad);
     ```
     
15.  Create a choropleth map based on the population attribute. Change the `fill-color` property of the layer.
     
     ```js
     map.addLayer(
        {
          'id': 'countries',
          'source': 'statesData',
          'source-layer': 'administrative',
          'type': 'fill',
          'filter': ['==', 'level', 0],
          'paint': {
              'fill-color': ['case',
                ['!=', ['to-number', ['feature-state', 'population']], 0],
                ['interpolate', ['linear'], ['feature-state', 'population'], 
                  5000000, 'rgba(222,235,247,1)', 90000000, 'rgba(49,130,189,1)'
                ],
                'rgba(0, 0, 0, 0)'
              ],
              'fill-opacity': 1,
              'fill-outline-color': '#000'
          }
        },
        firstSymbolId   
      );
     ```
     
16.  Display a popup when clicking on the vector layer and show the information of the age attribute.
     
     ```js
     map.on('click', 'countries', function (e) {
        new maptilersdk.Popup()
          .setLngLat(e.lngLat)
          .setHTML(`<h3>Population</h3><p>${e.features[0].state.population.toLocaleString()}</p>`)
          .addTo(map);
      });
     ```
     
17.  To make our map more user friendly, we will change the cursor when hovering over a geometry in the vector layer to indicate to the user that they can click on it.
     
     ```js
     // Change the cursor to a pointer when the mouse is over the layer.
      map.on('mouseenter', 'countries', function () {
          map.getCanvas().style.cursor = 'pointer';
      });
     
      // Change it back to a pointer when it leaves.
      map.on('mouseleave', 'countries', function () {
          map.getCanvas().style.cursor = '';
      });
     ```
     

## Basic JavaScript setup

1.  Copy the following code, paste it into your favorite text editor, and save it as a `.html` file.
    
    ```html
    <!DOCTYPE html>
     <html lang="en">
     <head>
       <meta charset="UTF-8">
       <meta name="viewport" content="width=device-width, initial-scale=1.0">
       <title>Display a countries choropleth map with your own data</title>
       <script src="https://cdn.maptiler.com/maptiler-sdk-js/v4.2.0/maptiler-sdk.umd.min.js"></script>
       <link href="https://cdn.maptiler.com/maptiler-sdk-js/v4.2.0/maptiler-sdk.css" rel="stylesheet" />
       <style>
         body { margin: 0; padding: 0; }
         #map { position: absolute; top: 0; bottom: 0; width: 100%; }
       </style>
     </head>
     <body>
       <div id="map"></div>
       <script>
           maptilersdk.config.apiKey = 'YOUR_MAPTILER_API_KEY_HERE';      
           const map = new maptilersdk.Map({
             container: 'map', // container's id or the HTML element to render the map
             style: maptilersdk.MapStyle.DATAVIZ.LIGHT,
                
             center: [13.39, 52.51], // starting position [lng, lat]
             zoom: 2, // starting zoom
                
           });
       </script>
     </body>
     </html>
    ```
    
2.  Replace `YOUR_MAPTILER_API_KEY_HERE` with [your own API key](https://cloud.maptiler.com/account/keys/). Make sure to [secure the key](https://docs.maptiler.com/guides/credentials/api-key/#secure-key) before you publish it.
    
3.  The next is up to you. You can center your map wherever you desire (modifying the `starting position`) and set an appropriate zoom level (modifying the `starting zoom`) to match your users’ needs. Additionally, you can change the map’s look (by updating the `source URL`); choose from a range of visually appealing map styles from our extensive [MapTiler standard maps](https://cloud.maptiler.com/maps/), or create your own to truly differentiate your application.
    
4.  Add event handler for map `load` event. You will add code to create a vector source and a vector layer in this handler.
    
    ```js
    map.on('load', function() {
    
     });
    ```
    
5.  Create vector source. The following snippet creates vector source for the MapTiler Countries dataset.
    
    ```js
    map.on('load', function() {
       map.addSource('statesData', {
         type: 'vector',
         url: `https://api.maptiler.com/tiles/countries/tiles.json`
       });
     });
    ```
    
6.  Get the id of the first symbol layer. We want to include the vector layer below the map labels. That means we need to know the id of the first symbol layer so we can include the vector layer before this layer.
    
    ```js
    // Find the id of the first symbol layer in the map style
     const layers = map.getStyle().layers;
     const firstSymbolId = layers.find(layer => layer.type === 'symbol').id;
    ```
    
7.  Add the vector layer. We need to include `firsSymbolId` to the `map.addLayer` function to display the vector under the maps labels
    
    ```js
    map.addLayer(
       {
         'id': 'countries',
         'source': 'statesData',
         'source-layer': 'administrative',
         'type': 'fill',
         'paint': {
             'fill-color': '#6B7C93',
             'fill-opacity': 1,
             'fill-outline-color': '#000'
         }
       },
       firstSymbolId   
     );
    ```
    
8.  Filter the data to only show the countries. Add a filter to the layer to only display level 0 items.
    
    ```js
    map.addLayer(
       {
         'id': 'countries',
         'source': 'statesData',
         'source-layer': 'administrative',
         'type': 'fill',
         'filter': ['==', 'level', 0],
         'paint': {
             'fill-color': '#6B7C93',
             'fill-opacity': 1,
             'fill-outline-color': '#000'
         }
       },
       firstSymbolId   
     );
    ```
    
9.  Prepare your data. Each feature in the dataset has its own identification for pairing. You need to mark your data with the same identifiers as is stored by features. We will use the iso\_n3 identifier for countries. Alternatively, you can use one of the properties: name, country codes (ISO A2), or wiki data-id. Check out the [Countries dataset schema](https://docs.maptiler.com/schema/countries/#administrative) to see the available fields.
    
    ```js
    const vizData = {
       "8":{"name":"Albania","population":2829741},
       "40":{"name":"Austria","population":8932664},
       "56":{"name":"Belgium","population":11566041},
       "100":{"name":"Bulgaria","population":6916548},
       "191":{"name":"Croatia","population":4036355},
       "196":{"name":"Cyprus","population":896005},
       "203":{"name":"Czechia","population":10701777},
       "208":{"name":"Denmark","population":5840045},
       "233":{"name":"Estonia","population":1330068},
       "246":{"name":"Finland","population":5533793},
       "250":{"name":"France","population":67439599},
       "276":{"name":"Germany","population":83155031},
       "300":{"name":"Greece","population":10682547},
       "348":{"name":"Hungary","population":9730772},
       "352":{"name":"Iceland","population":368792},
       "372":{"name":"Ireland","population":5006907},
       "380":{"name":"Italy","population":59257566},
       "428":{"name":"Latvia","population":1893223},
       "438":{"name":"Liechtenstein","population":39055},
       "440":{"name":"Lithuania","population":2795680},
       "442":{"name":"Luxembourg","population":634730},
       "470":{"name":"Malta","population":516100},
       "499":{"name":"Montenegro","population":620739},
       "528":{"name":"Netherlands","population":17475415},
       "578":{"name":"Norway","population":5391369},
       "616":{"name":"Poland","population":37840001},
       "620":{"name":"Portugal","population":10298252},
       "642":{"name":"Romania","population":19186201},
       "688":{"name":"Serbia","population":6871547},
       "703":{"name":"Slovakia","population":5459781},
       "705":{"name":"Slovenia","population":2108977},
       "724":{"name":"Spain","population":47394223},
       "752":{"name":"Sweden","population":10379295},
       "756":{"name":"Switzerland","population":8667088},
       "792":{"name":"Turkey","population":83614362},
       "807":{"name":"North Macedonia","population":2068808}
     };
    ```
    
10.  Join the data to coresponding features. Use `querySourceFeatures` to get all features from the layer for visualization. We are also filtering for all countries with `['==', 'level', 0]` using style expressions. The second part of the following code goes throw these features and adds attributes from our data array (vizData) to relevant features.
     
     ```js
     function setStates() {
        const countries = map.querySourceFeatures('statesData', {
          sourceLayer: 'administrative',
          filter: ['all', ['==', 'level', 0]],
        });
        countries.forEach(country => {
          if(country.id && vizData[country.id]) {
            map.setFeatureState({
              source: 'statesData',
              sourceLayer: 'administrative',
              id: country.id
            }, {
              population: vizData[country.id].population
            });
          }
        });
        if (countries.length !== 0) {
          map.off('data', afterLoad);
        }
      }
     ```
     
11.  Create a function that validates that the country dataset is loaded to call the `setStates` function.
     
     ```js
     function afterLoad() {
        if (map.getSource('statesData') && map.isSourceLoaded('statesData')) {
          setStates();
        }
      }
     ```
     
12.  Add event handler for map `data` event. Call the `afterLoad` function
     
     ```js
     map.on('data', afterLoad);
     ```
     
13.  Create a choropleth map based on the population attribute. Change the `fill-color` property of the layer.
     
     ```js
     map.addLayer(
        {
          'id': 'countries',
          'source': 'statesData',
          'source-layer': 'administrative',
          'type': 'fill',
          'filter': ['==', 'level', 0],
          'paint': {
              'fill-color': ['case',
                ['!=', ['to-number', ['feature-state', 'population']], 0],
                ['interpolate', ['linear'], ['feature-state', 'population'], 
                  5000000, 'rgba(222,235,247,1)', 90000000, 'rgba(49,130,189,1)'
                ],
                'rgba(0, 0, 0, 0)'
              ],
              'fill-opacity': 1,
              'fill-outline-color': '#000'
          }
        },
        firstSymbolId   
      );
     ```
     
14.  Display a popup when clicking on the vector layer and show the information of the age attribute.
     
     ```js
     map.on('click', 'countries', function (e) {
        new maptilersdk.Popup()
          .setLngLat(e.lngLat)
          .setHTML(`<h3>Population</h3><p>${e.features[0].state.population.toLocaleString()}</p>`)
          .addTo(map);
      });
     ```
     
15.  To make our map more user friendly, we will change the cursor when hovering over a geometry in the vector layer to indicate to the user that they can click on it.
     
     ```js
     // Change the cursor to a pointer when the mouse is over the layer.
      map.on('mouseenter', 'countries', function () {
          map.getCanvas().style.cursor = 'pointer';
      });
     
      // Change it back to a pointer when it leaves.
      map.on('mouseleave', 'countries', function () {
          map.getCanvas().style.cursor = '';
      });
     ```
     

### Complete source code

```html
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Display a countries choropleth map with your own data</title>
  <script src="https://cdn.maptiler.com/maptiler-sdk-js/v4.2.0/maptiler-sdk.umd.min.js"></script>
  <link href="https://cdn.maptiler.com/maptiler-sdk-js/v4.2.0/maptiler-sdk.css" rel="stylesheet" />
  <style>
    body {
      margin: 0;
      padding: 0;
    }
    #map {
      position: absolute;
      top: 0;
      bottom: 0;
      width: 100%;
    }
  </style>
</head>
<body>
  <div id="map"></div>
  <script>
      const vizData = {
        "8":{"name":"Albania","population":2829741},
        "40":{"name":"Austria","population":8932664},
        "56":{"name":"Belgium","population":11566041},
        "100":{"name":"Bulgaria","population":6916548},
        "191":{"name":"Croatia","population":4036355},
        "196":{"name":"Cyprus","population":896005},
        "203":{"name":"Czechia","population":10701777},
        "208":{"name":"Denmark","population":5840045},
        "233":{"name":"Estonia","population":1330068},
        "246":{"name":"Finland","population":5533793},
        "250":{"name":"France","population":67439599},
        "276":{"name":"Germany","population":83155031},
        "300":{"name":"Greece","population":10682547},
        "348":{"name":"Hungary","population":9730772},
        "352":{"name":"Iceland","population":368792},
        "372":{"name":"Ireland","population":5006907},
        "380":{"name":"Italy","population":59257566},
        "428":{"name":"Latvia","population":1893223},
        "438":{"name":"Liechtenstein","population":39055},
        "440":{"name":"Lithuania","population":2795680},
        "442":{"name":"Luxembourg","population":634730},
        "470":{"name":"Malta","population":516100},
        "499":{"name":"Montenegro","population":620739},
        "528":{"name":"Netherlands","population":17475415},
        "578":{"name":"Norway","population":5391369},
        "616":{"name":"Poland","population":37840001},
        "620":{"name":"Portugal","population":10298252},
        "642":{"name":"Romania","population":19186201},
        "688":{"name":"Serbia","population":6871547},
        "703":{"name":"Slovakia","population":5459781},
        "705":{"name":"Slovenia","population":2108977},
        "724":{"name":"Spain","population":47394223},
        "752":{"name":"Sweden","population":10379295},
        "756":{"name":"Switzerland","population":8667088},
        "792":{"name":"Turkey","population":83614362},
        "807":{"name":"North Macedonia","population":2068808}
      };
      function setStates() {
        const countries = map.querySourceFeatures('statesData', {
          sourceLayer: 'administrative',
          filter: ['all', ['==', 'level', 0]],
        });
        countries.forEach(country => {
          if(country.id && vizData[country.id]) {
            map.setFeatureState({
              source: 'statesData',
              sourceLayer: 'administrative',
              id: country.id
            }, {
              population: vizData[country.id].population
            });
          }
        });
        if (countries.length !== 0) {
          map.off('data', afterLoad);
        }
      }
      function afterLoad() {
        if (map.getSource('statesData') && map.isSourceLoaded('statesData')) {
          setStates();
        }
      }
      maptilersdk.config.apiKey = 'YOUR_MAPTILER_API_KEY_HERE';
      const map = new maptilersdk.Map({
        container: 'map', // container's id or the HTML element to render the map
        style: maptilersdk.MapStyle.DATAVIZ.LIGHT,
        center: [13.39, 52.51], // starting position [lng, lat]
        zoom: 2, // starting zoom
      });
      map.on('load', function() {
        map.addSource('statesData', {
          type: 'vector',
          url: `https://api.maptiler.com/tiles/countries/tiles.json?`
        });

        // Find the id of the first symbol layer in the map style
        const layers = map.getStyle().layers;
        const firstSymbolId = layers.find(layer => layer.type === 'symbol').id;
        
        map.addLayer(
          {
            'id': 'countries',
            'source': 'statesData',
            'source-layer': 'administrative',
            'type': 'fill',
            'filter': ['==', 'level', 0],
            'paint': {
                'fill-color': ['case',
                  ['!=', ['to-number', ['feature-state', 'population']], 0],
                  ['interpolate', ['linear'], ['feature-state', 'population'], 
                    5000000, 'rgba(222,235,247,1)', 90000000, 'rgba(49,130,189,1)'
                  ],
                  'rgba(0, 0, 0, 0)'
                ],
                'fill-opacity': 1,
                'fill-outline-color': '#000'
            }
          },
          firstSymbolId
        );
      });
      map.on('data', afterLoad);
      map.on('click', 'countries', function (e) {
        new maptilersdk.Popup()
          .setLngLat(e.lngLat)
          .setHTML(`<h3>Population</h3><p>${e.features[0].state.population.toLocaleString()}</p>`)
          .addTo(map);
      });
      // Change the cursor to a pointer when the mouse is over the layer.
      map.on('mouseenter', 'countries', function () {
          map.getCanvas().style.cursor = 'pointer';
      });

      // Change it back to a pointer when it leaves.
      map.on('mouseleave', 'countries', function () {
          map.getCanvas().style.cursor = '';
      });
  </script>
</body>
</html>
```

## Learn more

Check out the tutorials [How to use and filter data for MapTiler Countries](../countries-filter/) and [How to display an interactive choropleth map legend control](../control-legend-choropleth/).

Visit the [MapTiler Countries schema](https://docs.maptiler.com/schema/countries/) to know how it is organized into different thematic layers and which attribute and values each layer contains.

Read the following How-tos related to choropleth maps:

[How to style a choropleth map in Edit Tool](https://docs.maptiler.com/sdk-js/examples/countries-with-own-data/)

[Prepare GeoJSON with attributes for choropleth map and upload GeoJSON to MapTiler](https://docs.maptiler.com/guides/maps-apis/maps-platform/prepare-geojson-with-attributes-for-choropleth-map-and-upload-geojson-to-maptiler-cloud)

## Related examples

### [Countries filter](https://docs.maptiler.com/sdk-js/examples/countries-filter/)

Tutorials

Filter MapTiler Countries data to create choropleth maps.

### [Point filtering by property](https://docs.maptiler.com/sdk-js/examples/point-filtering/)

Examples

Filter features in real time by property.

### [Interactive choropleth map](https://docs.maptiler.com/sdk-js/examples/interactive-choropleth/)

Examples

Use events and feature states to create a interactive choropleth map.