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, chaque région administrative étant associée à une plage de valeurs numériques.
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;