A choropleth map is a type of thematic map in which administrative areas are
colored or shaded according to a data value. You can use a
google.maps.FeatureStyleFunction
to style a map based on a dataset where each administrative area is associated
with a range of numeric values. The following example map shows a choropleth map
depicting state population data for the United States.
In this example, the data consists of an array of key-value pairs, matching
the display name of each state with a numeric population value. The
maps.FeatureStyleFunction conditionally colors each region based on the
values in the array.
TypeScript
featureLayer.style = featureStyleFunctionOptions => {
const placeFeature = featureStyleFunctionOptions.feature as google.maps.PlaceFeature;
const population = states[placeFeature.placeId];
let fillColor;
// Specify colors using any of the following:
// * Named ('green')
// * Hexadecimal ('#FF0000')
// * RGB ('rgb(0, 0, 255)')
// * HSL ('hsl(60, 100%, 50%)')
if (population < 2000000) {
fillColor = 'green'
} else if (population < 5000000) {
fillColor = 'red'
} else if (population < 10000000) {
fillColor = 'blue'
} else if (population < 40000000) {
fillColor = 'yellow'
}
return {
fillColor,
fillOpacity: 0.5
}
}
JavaScript
featureLayer.style = (featureStyleFunctionOptions) => {
const placeFeature = featureStyleFunctionOptions.feature;
const population = states[placeFeature.placeId];
let fillColor;
// Specify colors using any of the following:
// * Named ('green')
// * Hexadecimal ('#FF0000')
// * RGB ('rgb(0, 0, 255)')
// * HSL ('hsl(60, 100%, 50%)')
if (population < 2000000) {
fillColor = "green";
} else if (population < 5000000) {
fillColor = "red";
} else if (population < 10000000) {
fillColor = "blue";
} else if (population < 40000000) {
fillColor = "yellow";
}
return {
fillColor,
fillOpacity: 0.5,
};
};
Complete example code
TypeScript
async function initMap() {
// Request needed libraries.
const { Map } = await google.maps.importLibrary("maps") as google.maps.MapsLibrary;
const map = new Map(document.getElementById('map') as HTMLElement, {
center: { lat: 40.76, lng: -101.64 },
zoom: 5,
// In the cloud console, configure this Map ID with a style that enables the
// "Administrative Area Level 1" feature layer.
mapId: '7ba16be0c9375fa7',
});
const featureLayer = map.getFeatureLayer(google.maps.FeatureType.ADMINISTRATIVE_AREA_LEVEL_1);
featureLayer.style = featureStyleFunctionOptions => {
const placeFeature = featureStyleFunctionOptions.feature as google.maps.PlaceFeature;
const population = states[placeFeature.placeId];
let fillColor;
// Specify colors using any of the following:
// * Named ('green')
// * Hexadecimal ('#FF0000')
// * RGB ('rgb(0, 0, 255)')
// * HSL ('hsl(60, 100%, 50%)')
if (population < 2000000) {
fillColor = 'green'
} else if (population < 5000000) {
fillColor = 'red'
} else if (population < 10000000) {
fillColor = 'blue'
} else if (population < 40000000) {
fillColor = 'yellow'
}
return {
fillColor,
fillOpacity: 0.5
}
}
// Population data by state.
const states = {
"ChIJdf5LHzR_hogR6czIUzU0VV4": 5039877, // Alabama
"ChIJG8CuwJzfAFQRNduKqSde27w": 732673, // Alaska
"ChIJaxhMy-sIK4cRcc3Bf7EnOUI": 7276316, // Arizona
"ChIJYSc_dD-e0ocR0NLf_z5pBaQ": 3025891, // Arkansas
"ChIJPV4oX_65j4ARVW8IJ6IJUYs": 39237836, // California
"ChIJt1YYm3QUQIcR_6eQSTGDVMc": 5812069, // Colorado
"ChIJpVER8hFT5okR5XBhBVttmq4": 3605597, // Connecticut
"ChIJO9YMTXYFx4kReOgEjBItHZQ": 1003384, // Delaware
"ChIJvypWkWV2wYgR0E7HW9MTLvc": 21781128, // Florida
"ChIJV4FfHcU28YgR5xBP7BC8hGY": 10799566, // Georgia
"ChIJBeB5Twbb_3sRKIbMdNKCd0s": 1441553, // Hawaii
"ChIJ6Znkhaj_WFMRWIf3FQUwa9A": 1900923, // Idaho
"ChIJGSZubzgtC4gRVlkRZFCCFX8": 12671469, // Illinois
"ChIJHRv42bxQa4gRcuwyy84vEH4": 6805985, // Indiana
"ChIJGWD48W9e7ocR2VnHV0pj78Y": 3193079, // Iowa
"ChIJawF8cXEXo4cRXwk-S6m0wmg": 2934582, // Kansas
"ChIJyVMZi0xzQogR_N_MxU5vH3c": 4509394, // Kentucky
"ChIJZYIRslSkIIYRA0flgTL3Vck": 4624047, // Louisiana
"ChIJ1YpTHd4dsEwR0KggZ2_MedY": 1372247, // Maine
"ChIJ35Dx6etNtokRsfZVdmU3r_I": 6165129, // Maryland
"ChIJ_b9z6W1l44kRHA2DVTbQxkU": 6984723, // Massachussetts
"ChIJEQTKxz2qTE0Rs8liellI3Zc": 10050811, // Michigan
"ChIJmwt4YJpbWE0RD6L-EJvJogI": 5707390, // Minnesota
"ChIJGdRK5OQyKIYR2qbc6X8XDWI": 2949965, // Mississippi
"ChIJfeMiSNXmwIcRcr1mBFnEW7U": 6168187, // Misssouri
"ChIJ04p7LZwrQVMRGGwqz1jWcfU": 1104271, // Montana
"ChIJ7fwMtciNk4cRxArzDwyQJ6E": 1963692, // Nebraska
"ChIJcbTe-KEKmYARs5X8qooDR88": 3143991, // Nevada
"ChIJ66bAnUtEs0wR64CmJa8CyNc": 1388992, // New Hampshire
"ChIJn0AAnpX7wIkRjW0_-Ad70iw": 9267130, // New Jersey
"ChIJqVKY50NQGIcRup41Yxpuv0Y": 2115877, // New Mexico
"ChIJqaUj8fBLzEwRZ5UY3sHGz90": 19835913, // New York
"ChIJgRo4_MQfVIgRGa4i6fUwP60": 10551162, // North Carolina
"ChIJY-nYVxKD11IRyc9egzmahA0": 774948, // North Dakota
"ChIJwY5NtXrpNogRFtmfnDlkzeU": 11780017, // Ohio
"ChIJnU-ssRE5rIcRSOoKQDPPHF0": 3986639, // Oklahoma
"ChIJVWqfm3xuk1QRdrgLettlTH0": 4246155, // Oregon
"ChIJieUyHiaALYgRPbQiUEchRsI": 12964056, // Pennsylvania
"ChIJD9cOYhQ15IkR5wbB57wYTh4": 1095610, // Rhode Island
"ChIJ49ExeWml-IgRnhcF9TKh_7k": 5190705, // South Carolina
"ChIJpTjphS1DfYcRt6SGMSnW8Ac": 895376, // South Dakota
"ChIJA8-XniNLYYgRVpGBpcEgPgM": 6975218, // Tennessee
"ChIJSTKCCzZwQIYRPN4IGI8c6xY": 29527941, // Texas
"ChIJzfkTj8drTIcRP0bXbKVK370": 3337975, // Utah
"ChIJ_87aSGzctEwRtGtUNnSJTSY": 645570, // Vermont
"ChIJzbK8vXDWTIgRlaZGt0lBTsA": 8642274, // Virginia
"ChIJ-bDD5__lhVQRuvNfbGh4QpQ": 7738692, // Washington
"ChIJRQnL1KVUSogRQzrN3mjHALs": 1782959, // West Virginia
"ChIJr-OEkw_0qFIR1kmG-LjV1fI": 5895908, // Wisconsin
"ChIJaS7hSDTiXocRLzh90nkisCY": 578803, // Wyoming
};
}
initMap();
JavaScript
async function initMap() {
// Request needed libraries.
const { Map } = await google.maps.importLibrary("maps");
const map = new Map(document.getElementById("map"), {
center: { lat: 40.76, lng: -101.64 },
zoom: 5,
// In the cloud console, configure this Map ID with a style that enables the
// "Administrative Area Level 1" feature layer.
mapId: "7ba16be0c9375fa7",
});
const featureLayer = map.getFeatureLayer(
google.maps.FeatureType.ADMINISTRATIVE_AREA_LEVEL_1,
);
featureLayer.style = (featureStyleFunctionOptions) => {
const placeFeature = featureStyleFunctionOptions.feature;
const population = states[placeFeature.placeId];
let fillColor;
// Specify colors using any of the following:
// * Named ('green')
// * Hexadecimal ('#FF0000')
// * RGB ('rgb(0, 0, 255)')
// * HSL ('hsl(60, 100%, 50%)')
if (population < 2000000) {
fillColor = "green";
} else if (population < 5000000) {
fillColor = "red";
} else if (population < 10000000) {
fillColor = "blue";
} else if (population < 40000000) {
fillColor = "yellow";
}
return {
fillColor,
fillOpacity: 0.5,
};
};
// Population data by state.
const states = {
"ChIJdf5LHzR_hogR6czIUzU0VV4": 5039877,
"ChIJG8CuwJzfAFQRNduKqSde27w": 732673,
"ChIJaxhMy-sIK4cRcc3Bf7EnOUI": 7276316,
"ChIJYSc_dD-e0ocR0NLf_z5pBaQ": 3025891,
"ChIJPV4oX_65j4ARVW8IJ6IJUYs": 39237836,
"ChIJt1YYm3QUQIcR_6eQSTGDVMc": 5812069,
"ChIJpVER8hFT5okR5XBhBVttmq4": 3605597,
"ChIJO9YMTXYFx4kReOgEjBItHZQ": 1003384,
"ChIJvypWkWV2wYgR0E7HW9MTLvc": 21781128,
"ChIJV4FfHcU28YgR5xBP7BC8hGY": 10799566,
"ChIJBeB5Twbb_3sRKIbMdNKCd0s": 1441553,
"ChIJ6Znkhaj_WFMRWIf3FQUwa9A": 1900923,
"ChIJGSZubzgtC4gRVlkRZFCCFX8": 12671469,
"ChIJHRv42bxQa4gRcuwyy84vEH4": 6805985,
"ChIJGWD48W9e7ocR2VnHV0pj78Y": 3193079,
"ChIJawF8cXEXo4cRXwk-S6m0wmg": 2934582,
"ChIJyVMZi0xzQogR_N_MxU5vH3c": 4509394,
"ChIJZYIRslSkIIYRA0flgTL3Vck": 4624047,
"ChIJ1YpTHd4dsEwR0KggZ2_MedY": 1372247,
"ChIJ35Dx6etNtokRsfZVdmU3r_I": 6165129,
"ChIJ_b9z6W1l44kRHA2DVTbQxkU": 6984723,
"ChIJEQTKxz2qTE0Rs8liellI3Zc": 10050811,
"ChIJmwt4YJpbWE0RD6L-EJvJogI": 5707390,
"ChIJGdRK5OQyKIYR2qbc6X8XDWI": 2949965,
"ChIJfeMiSNXmwIcRcr1mBFnEW7U": 6168187,
"ChIJ04p7LZwrQVMRGGwqz1jWcfU": 1104271,
"ChIJ7fwMtciNk4cRxArzDwyQJ6E": 1963692,
"ChIJcbTe-KEKmYARs5X8qooDR88": 3143991,
"ChIJ66bAnUtEs0wR64CmJa8CyNc": 1388992,
"ChIJn0AAnpX7wIkRjW0_-Ad70iw": 9267130,
"ChIJqVKY50NQGIcRup41Yxpuv0Y": 2115877,
"ChIJqaUj8fBLzEwRZ5UY3sHGz90": 19835913,
"ChIJgRo4_MQfVIgRGa4i6fUwP60": 10551162,
"ChIJY-nYVxKD11IRyc9egzmahA0": 774948,
"ChIJwY5NtXrpNogRFtmfnDlkzeU": 11780017,
"ChIJnU-ssRE5rIcRSOoKQDPPHF0": 3986639,
"ChIJVWqfm3xuk1QRdrgLettlTH0": 4246155,
"ChIJieUyHiaALYgRPbQiUEchRsI": 12964056,
"ChIJD9cOYhQ15IkR5wbB57wYTh4": 1095610,
"ChIJ49ExeWml-IgRnhcF9TKh_7k": 5190705,
"ChIJpTjphS1DfYcRt6SGMSnW8Ac": 895376,
"ChIJA8-XniNLYYgRVpGBpcEgPgM": 6975218,
"ChIJSTKCCzZwQIYRPN4IGI8c6xY": 29527941,
"ChIJzfkTj8drTIcRP0bXbKVK370": 3337975,
"ChIJ_87aSGzctEwRtGtUNnSJTSY": 645570,
"ChIJzbK8vXDWTIgRlaZGt0lBTsA": 8642274,
"ChIJ-bDD5__lhVQRuvNfbGh4QpQ": 7738692,
"ChIJRQnL1KVUSogRQzrN3mjHALs": 1782959,
"ChIJr-OEkw_0qFIR1kmG-LjV1fI": 5895908,
"ChIJaS7hSDTiXocRLzh90nkisCY": 578803, // Wyoming
};
}
initMap();
CSS
/*
* Always set the map height explicitly to define the size of the div element
* that contains the map.
*/
#map {
height: 100%;
}
/*
* Optional: Makes the sample page fill the window.
*/
html,
body {
height: 100%;
margin: 0;
padding: 0;
}
HTML
<html>
<head>
<title>Choropleth Map</title>
<script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>
<link rel="stylesheet" type="text/css" href="./style.css" />
<script type="module" src="./index.js"></script>
</head>
<body>
<div id="map"></div>
<!-- prettier-ignore -->
<script>(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: "AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg", v: "weekly"});</script>
</body>
</html>