Choroplethenkarten erstellen

Eine Choroplethenkarte (Intensitätskarte) ist eine thematische Karte, bei der Verwaltungsgebiete gemäß einem statistischen Bereich eingefärbt bzw. schattiert werden. Mit google.maps.FeatureStyleFunction können Sie den Stil einer Karte basierend auf einem Datensatz definieren, wobei jedem Verwaltungsbereich ein numerischer Wert zugeordnet ist. Die folgende Beispielkarte zeigt eine Choroplethenkarte mit Bevölkerungsdaten der einzelnen Bundesstaaten in den USA.

In diesem Beispiel bestehen die Daten aus einem Array von Schlüssel/Wert-Paaren, bei dem der Anzeigename eines Bundesstaates mit einem numerischen Wert für die Bevölkerung verknüpft ist. Über maps.FeatureStyleFunction wird die Farbe für die einzelnen Regionen je nach Wert im Array unter bestimmten Bedingungen festgelegt.

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
    }
}

// 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
};

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,
  };
};

// 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
};

Vollständiges Codebeispiel

TypeScript

function initMap() {
    const map = new google.maps.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',
    });

    //@ts-ignore
    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
    };
}

declare global {
    interface Window {
        initMap: () => void;
    }
}
window.initMap = initMap;

JavaScript

function initMap() {
  const map = new google.maps.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",
  });
  //@ts-ignore
  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
  };
}

window.initMap = 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>

    <!--
      The `defer` attribute causes the callback to execute after the full HTML
      document has been parsed. For non-blocking uses, avoiding race conditions,
      and consistent behavior across browsers, consider loading using Promises.
      See https://developers.google.com/maps/documentation/javascript/load-maps-js-api
      for more information.
      -->
    <script
      src="https://maps.googleapis.com/maps/api/js?key=AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg&callback=initMap&v=beta"
      defer
    ></script>
  </body>
</html>

Testbeispiel