Créer une carte choroplèthe

Sélectionnez une plate-forme : Android iOS JavaScript

Une carte choroplèthe est un type de carte thématique dans laquelle les régions administratives sont colorées ou nuancées en fonction d'une valeur de données. Vous pouvez utiliser GMSFeatureLayer pour styliser une carte en fonction de données où chaque région administrative est associée à une plage de valeurs numériques.

Schéma illustrant une carte choroplèthe de limites

Dans cet exemple, les données sont constituées d'un tableau de paires clé/valeur, correspondant au nom à afficher de chaque État avec une valeur numérique de population.

Swift

//..

let featureLayer = mapView.featureLayer(of: FeatureType.administrativeAreaLevel1)

let populationOfStates = [
"ChIJdf5LHzR_hogR6czIUzU0VV4": 5_039_877,
"ChIJG8CuwJzfAFQRNduKqSde27w": 732673,
"ChIJaxhMy-sIK4cRcc3Bf7EnOUI": 7_276_316,
"ChIJYSc_dD-e0ocR0NLf_z5pBaQ": 3_025_891,
"ChIJPV4oX_65j4ARVW8IJ6IJUYs": 39_237_836,  // California
"ChIJt1YYm3QUQIcR_6eQSTGDVMc": 5_812_069,
"ChIJpVER8hFT5okR5XBhBVttmq4": 3_605_597,
"ChIJO9YMTXYFx4kReOgEjBItHZQ": 1_003_384,
"ChIJvypWkWV2wYgR0E7HW9MTLvc": 21_781_128,
"ChIJV4FfHcU28YgR5xBP7BC8hGY": 10_799_566,
"ChIJBeB5Twbb_3sRKIbMdNKCd0s": 1_441_553,
"ChIJ6Znkhaj_WFMRWIf3FQUwa9A": 1_900_923,
"ChIJGSZubzgtC4gRVlkRZFCCFX8": 12_671_469,
"ChIJHRv42bxQa4gRcuwyy84vEH4": 6_805_985,
"ChIJGWD48W9e7ocR2VnHV0pj78Y": 3_193_079,
"ChIJawF8cXEXo4cRXwk-S6m0wmg": 2_934_582,
"ChIJyVMZi0xzQogR_N_MxU5vH3c": 4_509_394,
"ChIJZYIRslSkIIYRA0flgTL3Vck": 4_624_047,
"ChIJ1YpTHd4dsEwR0KggZ2_MedY": 1_372_247,
"ChIJ35Dx6etNtokRsfZVdmU3r_I": 6_165_129,
"ChIJ_b9z6W1l44kRHA2DVTbQxkU": 6_984_723,
"ChIJEQTKxz2qTE0Rs8liellI3Zc": 10_050_811,
"ChIJmwt4YJpbWE0RD6L-EJvJogI": 5_707_390,
"ChIJGdRK5OQyKIYR2qbc6X8XDWI": 2_949_965,
"ChIJfeMiSNXmwIcRcr1mBFnEW7U": 6_168_187,
"ChIJ04p7LZwrQVMRGGwqz1jWcfU": 1_104_271,
"ChIJ7fwMtciNk4cRxArzDwyQJ6E": 1_963_692,
"ChIJcbTe-KEKmYARs5X8qooDR88": 3_143_991,
"ChIJ66bAnUtEs0wR64CmJa8CyNc": 1_388_992,
"ChIJn0AAnpX7wIkRjW0_-Ad70iw": 9_267_130,
"ChIJqVKY50NQGIcRup41Yxpuv0Y": 2_115_877,
"ChIJqaUj8fBLzEwRZ5UY3sHGz90": 19_835_913,
"ChIJgRo4_MQfVIgRGa4i6fUwP60": 10_551_162,
"ChIJY-nYVxKD11IRyc9egzmahA0": 774948,
"ChIJwY5NtXrpNogRFtmfnDlkzeU": 11_780_017,
"ChIJnU-ssRE5rIcRSOoKQDPPHF0": 3_986_639,
"ChIJVWqfm3xuk1QRdrgLettlTH0": 4_246_155,
"ChIJieUyHiaALYgRPbQiUEchRsI": 12_964_056,
"ChIJD9cOYhQ15IkR5wbB57wYTh4": 1_095_610,
"ChIJ49ExeWml-IgRnhcF9TKh_7k": 5_190_705,
"ChIJpTjphS1DfYcRt6SGMSnW8Ac": 895376,
"ChIJA8-XniNLYYgRVpGBpcEgPgM": 6_975_218,
"ChIJSTKCCzZwQIYRPN4IGI8c6xY": 29_527_941,
"ChIJzfkTj8drTIcRP0bXbKVK370": 3_337_975,
"ChIJ_87aSGzctEwRtGtUNnSJTSY": 645570,
"ChIJzbK8vXDWTIgRlaZGt0lBTsA": 8_642_274,
"ChIJ-bDD5__lhVQRuvNfbGh4QpQ": 7_738_692,
"ChIJRQnL1KVUSogRQzrN3mjHALs": 1_782_959,
"ChIJr-OEkw_0qFIR1kmG-LjV1fI": 5_895_908,
"ChIJaS7hSDTiXocRLzh90nkisCY": 578803,  // Wyoming
]

featureLayer.style = { feature in
  FeatureStyle(
    fill: populationOfStates[feature.placeID].map {
      UIColor(
        hue: log(CGFloat($0) / 5e5) / 7.5,
        saturation: 1,
        brightness: 0.75,
        alpha: 0.5)
    } ?? nil,
    stroke: nil,
    strokeWidth: 0
  )
}

self.view = mapView

Objective-C

//..

GMSFeatureLayer<GMSPlaceFeature *> *featureLayer =
    [mapView featureLayerOfFeatureType:GMSFeatureTypeAdministrativeAreaLevel1];

NSDictionary<NSString *, NSNumber *> *populationOfStates = @{
  @"ChIJdf5LHzR_hogR6czIUzU0VV4" : @(5039877),
  @"ChIJG8CuwJzfAFQRNduKqSde27w" : @(732673),
  @"ChIJaxhMy-sIK4cRcc3Bf7EnOUI" : @(7276316),
  @"ChIJYSc_dD-e0ocR0NLf_z5pBaQ" : @(3025891),
  @"ChIJPV4oX_65j4ARVW8IJ6IJUYs" : @(39237836),  // California
  @"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
};

featureLayer.style = ^(GMSPlaceFeature *feature) {
  NSNumber *population = populationOfStates[feature.placeID];
  UIColor *fillColor = population ? [UIColor colorWithHue:(log(population.doubleValue / 5e5) / 7.5) saturation:1 brightness:0.5 alpha:0.5] : nil;
  return [GMSFeatureStyle styleWithFillColor:fillColor strokeColor:nil strokeWidth:0.0];
};

self.view = mapView;