Style polygon data features with color

This example shows an approach to styling polygon geometry based data features.

Read the documentation.

TypeScript

const mapElement = document.querySelector('gmp-map')!;
let innerMap: google.maps.Map;
const setStyle: google.maps.FeatureStyleFunction = (params) => {
    const datasetFeature = params.feature as google.maps.DatasetFeature;
    // 'typecategory' is an attribute in this Dataset.
    const typeCategory = datasetFeature.datasetAttributes.typecategory;

    switch (typeCategory) {
        case 'Undeveloped': // Color undeveloped areas blue.
            return {
                strokeColor: 'blue',
                strokeWeight: 2,
                strokeOpacity: 1,
                fillColor: 'blue',
                fillOpacity: 0.3,
            };
            break;
        case 'Parkway': // Color historical house sites red.
            return {
                strokeColor: 'red',
                strokeWeight: 2,
                strokeOpacity: 1,
                fillColor: 'red',
                fillOpacity: 0.5,
            };
            break;
        default: // Color other type categories green.
            return {
                strokeColor: 'green',
                strokeWeight: 2,
                strokeOpacity: 1,
                fillColor: 'green',
                fillOpacity: 0.3,
            };
            break;
    }
};

async function init() {
    // Request needed libraries.
    await google.maps.importLibrary('maps');

    // Get the inner map.
    innerMap = mapElement.innerMap;

    // Dataset ID for NYC park data.
    const datasetId = 'a75dd002-ad20-4fe6-af60-27cd2ed636b4';
    const datasetLayer = innerMap.getDatasetFeatureLayer(datasetId);
    datasetLayer.style = setStyle;
}

void init();
index.ts

Note: Read the guide on using TypeScript and Google Maps.

JavaScript

const mapElement = document.querySelector('gmp-map');
let innerMap;
const setStyle = (params) => {
    const datasetFeature = params.feature;
    // 'typecategory' is an attribute in this Dataset.
    const typeCategory = datasetFeature.datasetAttributes.typecategory;

    switch (typeCategory) {
        case 'Undeveloped': // Color undeveloped areas blue.
            return {
                strokeColor: 'blue',
                strokeWeight: 2,
                strokeOpacity: 1,
                fillColor: 'blue',
                fillOpacity: 0.3,
            };
            break;
        case 'Parkway': // Color historical house sites red.
            return {
                strokeColor: 'red',
                strokeWeight: 2,
                strokeOpacity: 1,
                fillColor: 'red',
                fillOpacity: 0.5,
            };
            break;
        default: // Color other type categories green.
            return {
                strokeColor: 'green',
                strokeWeight: 2,
                strokeOpacity: 1,
                fillColor: 'green',
                fillOpacity: 0.3,
            };
            break;
    }
};

async function init() {
    // Request needed libraries.
    await google.maps.importLibrary('maps');

    // Get the inner map.
    innerMap = mapElement.innerMap;

    // Dataset ID for NYC park data.
    const datasetId = 'a75dd002-ad20-4fe6-af60-27cd2ed636b4';
    const datasetLayer = innerMap.getDatasetFeatureLayer(datasetId);
    datasetLayer.style = setStyle;
}

void init();
index.js

CSS

/* 
 * Optional: Makes the sample page fill the window. 
 */
html,
body {
    height: 100%;
    margin: 0;
    padding: 0;
}

#attribution {
    background-color: rgba(255, 255, 255, 0.7);
    font-family: 'Roboto', 'Arial', sans-serif;
    font-size: 10px;
    padding: 2px;
    margin: 2px;
}
style.css

HTML

<html>
    <head>
        <title>Style a polygon data feature with more detail</title>

        <link rel="stylesheet" type="text/css" href="./style.css" />
        <script type="module" src="./index.js"></script>
        <script>
            // prettier-ignore
            (g=>{var h,a,k,p="The Google Maps JavaScript API",c="google",l="importLibrary",q="__ib__",m=document,b=window;b=b[c]||(b[c]={});var d=b.maps||(b.maps={}),r=new Set,e=new URLSearchParams,u=()=>h||(h=new Promise(async(f,n)=>{await (a=m.createElement("script"));e.set("libraries",[...r]+"");for(k in g)e.set(k.replace(/[A-Z]/g,t=>"_"+t[0].toLowerCase()),g[k]);e.set("callback",c+".maps."+q);a.src=`https://maps.${c}apis.com/maps/api/js?`+e;d[q]=f;a.onerror=()=>h=n(Error(p+" could not load."));a.nonce=m.querySelector("script[nonce]")?.nonce||"";m.head.append(a)}));d[l]?console.warn(p+" only loads once. Ignoring:",g):d[l]=(f,...n)=>r.add(f)&&u().then(()=>d[l](f,...n))})({
                key: "GOOGLE_MAPS_API_KEY"
            });
        </script>
    </head>
    <body>
        <gmp-map
            center="40.580732, -74.152826"
            zoom="14"
            map-id="5cd2c9ca1cf05670">
            <div id="attribution" slot="control-block-end-inline-start">
                Data source: NYC Open Data
            </div>
        </gmp-map>
    </body>
</html>
index.html

Clone Sample

Git and Node.js are required to run this sample locally. Follow these instructions to install Node.js and NPM. You will also need a Google Maps API key.

The following commands clone the repository, install dependencies, and copy the environment file.

  git clone https://github.com/googlemaps-samples/js-api-samples.git
  cd js-api-samples
  npm i
  cp .env.template .env

Once you copy the environment file, make sure to open the .env file and replace <Insert your own development API key here> with your actual API key before starting the sample.

  cd samples/dds-datasets-polygon-colors
  npm start