样式数据地图项示例

此页面介绍如何以程序化方式访问数据集并设置其地图项的样式。 并逐步讲解基于点、多边形和各种数据地图项的样式设置示例， 以及多段线几何图形

在对数据集进行数据驱动型样式设置时，系统会基于创建数据集时所用的地理空间数据文件中提供的经纬度坐标来渲染数据地图项。

点数据的样式设置示例

本例演示了如何为基于点几何图形的数据地图项设置样式。

将样式应用于表示松鼠颜色的地图项。

关于数据集

本例中使用的数据集是 2018 年松鼠调查 美国纽约市中央公园的景点。 在 CSV 数据文件的以下代码段中，我们看到 x 和 y 列 用于表示地理位置；包含 LatLng 列，但此列未用于 因为数据集仅支持 WKT 格式 如果列名为 WKT。如需详细了解支持的格式 有关位置，请参阅 CSV 要求。

松鼠普查数据集包含大量不同的数据点 与观察到的松鼠毛色和行为相关（请务必滚动浏览 水平可查看所有内容）。

X Y UniqueSquirrelID Hectare Shift Date Hectare SquirrelNumber Age PrimaryFurColor HighlightFurColor CombinationofPrimaryandHighlightColor Colornotes Location AboveGroundSighter Measurement SpecificLocation Running Chasing Climbing Eating Foraging Other Activities Kuks Quaas Moans Tailflags Tailtwitches Approaches Indifferent Runsfrom OtherInteractions LatLng
-73.9561344937861 40.7940823884086 37F-PM-1014-03 37F PM 10142018 3 + false false false false false false false false false false false false false POINT (-73.9561344937861 40.7940823884086)
-73.9688574691102 40.7837825208444 21B-AM-1019-04 21B AM 10192018 4 + false false false false false false false false false false false false false POINT (-73.9688574691102 40.7837825208444)
-73.9742811484852 40.775533619083 11B-PM-1014-08 11B PM 10142018 8 Gray Gray+ Above Ground 10 false true false false false false false false false false false false false POINT (-73.97428114848522 40.775533619083)
-73.9596413903948 40.7903128889029 32E-PM-1017-14 32E PM 10172018 14 Adult Gray Gray+ Nothing selected as Primary. Gray selected as Highlights. Made executive adjustments. false false false true true false false false false false false false true POINT (-73.9596413903948 40.7903128889029)
-73.9702676472613 40.7762126854894 13E-AM-1017-05 13E AM 10172018 5 Adult Gray Cinnamon Gray+Cinnamon Above Ground on tree stump false false false false true false false false false false false false false POINT (-73.9702676472613 40.7762126854894)
-73.9683613516225 40.7725908847499 11H-AM-1010-03 11H AM 10102018 3 Adult Cinnamon White Cinnamon+White false false false false true false false false false true false true false POINT (-73.9683613516225 40.7725908847499)
-73.9541201789795 40.7931811701082 36H-AM-1010-02 36H AM 10102018 2 Adult Gray Gray+ just outside hectare Ground Plane FALSE false false false false true false false false false false false false false POINT (-73.9541201789795 40.7931811701082)

设置点数据地图项的样式

此示例中的代码采用设置填充颜色样式的方法， 根据 CombinationofPrimaryandHighlightColor 为每个点的描边颜色 属性，该属性组合了每件商品的主要和次要的皮草颜色 松鼠。

Swift

let mapView = GMSMapView(frame: .zero, mapID: GMSMapID(identifier: "YOUR_MAP_ID"), camera: GMSCameraPosition(latitude: 40.7, longitude: -74.0, zoom: 12))

let layer = mapView.datasetFeatureLayer(of: "YOUR_DATASET_ID")

// Define a point style with fill and radius.
// Apply the style to the datasets features.
layer.style = { feature in
    switch(feature.datasetAttributes["CombinationofPrimaryandHighlightColor"]){
      case "Black+"  :
        let style = MutableFeatureStyle()
        style.fillColor = .black;
        style.pointRadius = 8;
        return style
      case "Cinnamon+"  :
        let style = MutableFeatureStyle()
        style.fillColor = UIColor(red: 139/255, green: 0, blue: 0, alpha: 1);
        style.pointRadius = 8;
        return style
      ...
      default :
        let style = MutableFeatureStyle()
        style.fillColor = .yellow;
        style.pointRadius = 8;
        return style
    }
}

Objective-C

GMSMapView *mapView = [GMSMapView mapWithFrame:CGRectZero mapID:[GMSMapID mapIDWithIdentifier:@"MAP_ID"] camera:[GMSCameraPosition cameraWithLatitude: 40.7 longitude: -74.0 zoom:12]];

GMSDatasetFeatureLayer *layer = [mapView datasetFeatureLayerOfDatasetID:@"YOUR_DATASET_ID"];

// Define a point style with fill and radius.
// Apply the style to the datasets features.
layer.style = ^(GMSDatasetFeature *feature) {
  NSString *attrib = feature.datasetAttributes[@"CombinationofPrimaryandHighlightColor"];
  if ([attrib isEqualToString:@"Black+"])  {
    GMSMutableFeatureStyle *style = [GMSMutableFeatureStyle style];
    style.fillColor = [UIColor blackColor];
    style.pointRadius = 8;
    return style;
  } else if([attrib isEqualToString:@"Cinnamon+"]) {
    GMSMutableFeatureStyle *style = [GMSMutableFeatureStyle style];
    style.fillColor = [UIColor colorWithRed:139.0f/255.0f
                                      green:0.0f
                                        blue:0.0f
                                      alpha:1.0f];
    style.pointRadius = 8;
    return style;
  }
  ...
  else {
    GMSMutableFeatureStyle *style = [GMSMutableFeatureStyle style];
    style.fillColor = [UIColor yellowColor];
    style.pointRadius = 8;
    return style;
  }
};

多边形数据的样式设置示例

本例演示了如何为基于多边形几何图形的数据地图项设置样式。

将样式应用于表示公园类型的地图项。

关于数据集

本例中使用的数据集描述的是 纽约市的公园。 以下内容摘录自 GeoJSON 数据集文件，显示了一个具有代表性的地图项条目。

{
  "type": "Feature",
  "properties": {
    "jurisdiction": "DPR",
    "mapped": "False",
    "zipcode": "11356",
    "acres": "0.05",
    "location": "College Pl., College Pt. Blvd., bet. 11 Ave. and 12 Ave.",
    "nys_assembly": "27",
    "councildistrict": "19",
    "url": "http://www.nycgovparks.org/parks/Q042/",
    "typecategory": "Triangle/Plaza",
    "us_congress": "14",
    "eapply": "Poppenhusen Park",
    "parentid": "Q-07",
    "gispropnum": "Q042",
    "retired": "false",
    "communityboard": "407",
    "objectid": "6248",
    "globalid": "F4810079-CBB9-4BE7-BBFA-B3C0C35D5DE5",
    "name311": "Poppenhusen Park",
    "department": "Q-07",
    "pip_ratable": "true",
    "subcategory": "Sitting Area/Triangle/Mall",
    "precinct": "109",
    "permit": "true",
    "acquisitiondate": null,
    "omppropid": "Q042",
    "gisobjid": "100000301",
    "signname": "Poppenhusen Park",
    "address": null,
    "permitparent": "Q-07",
    "class": "PARK",
    "nys_senate": "11",
    "permitdistrict": "Q-07",
    "borough": "Q",
    "waterfront": "false"
  },
  "geometry": {
    "type": "MultiPolygon",
    "coordinates": [
      [
        [
          [
            -73.84575702371716,
            40.78796240884273
          ],
          [
            -73.84593393292693,
            40.78796857347548
          ],
          [
            -73.84577256469657,
            40.787651355629556
          ],
          [
            -73.84575702371716,
            40.78796240884273
          ]
        ]
      ]
    ]
  }
},

设置多边形数据地图项的样式

本例中的代码将特殊颜色应用于 typecategory 为“Undeveloped”或“Parkway”的数据地图项，并将所有其他地图项的颜色设为绿色。

Swift

let mapView = GMSMapView(frame: .zero, mapID: GMSMapID(identifier: "YOUR_MAP_ID"), camera: GMSCameraPosition(latitude: 40.7, longitude: -74.0, zoom: 12))

let layer = mapView.datasetFeatureLayer(of: "YOUR_DATASET_ID")

// Define a polygon style with fill and stroke.
// Apply the style to the datasets features.
layer.style = { feature in
  switch(feature.datasetAttributes["typecategory"]){
    case "Undeveloped"  :
      let style = MutableFeatureStyle()
      style.fillColor = .blue.withAlphaComponent(0.3);
      style.strokeColor = .blue;
      style.strokeWidth = 2.0;
      return style
    case "Parkway"  :
      let style = MutableFeatureStyle()
      style.fillColor = .red.withAlphaComponent(0.3);
      style.strokeColor = .red;
      style.strokeWidth = 2.0;
      return style
    default :
      let style = MutableFeatureStyle()
      style.fillColor = .green.withAlphaComponent(0.3);
      style.strokeColor = .green;
      style.strokeWidth = 2.0;
      return style
  }
}

Objective-C

GMSMapView *mapView = [GMSMapView mapWithFrame:CGRectZero mapID:[GMSMapID mapIDWithIdentifier:@"MAP_ID"] camera:[GMSCameraPosition cameraWithLatitude: 40.7 longitude: -74.0 zoom:12]];

GMSDatasetFeatureLayer *layer = [mapView datasetFeatureLayerOfDatasetID:@"YOUR_DATASET_ID"];

// Define a polygon style with fill and stroke.
// Apply the style to the datasets features.
layer.style = ^(GMSDatasetFeature *feature) {
  NSString *attrib = feature.datasetAttributes[@"typecategory"];
  if ([attrib isEqualToString:@"Undeveloped"]) {
        GMSMutableFeatureStyle *style = [GMSMutableFeatureStyle style];
        style.fillColor = [[UIColor blueColor] colorWithAlphaComponent:0.3];
        style.strokeColor = [UIColor blueColor];
        style.strokeWidth = 2.0;
        return style;
  } else if([attrib isEqualToString:@"Parkway"]) {
        GMSMutableFeatureStyle *style = [GMSMutableFeatureStyle style];
        style.fillColor = [[UIColor redColor] colorWithAlphaComponent:0.3];
        style.strokeColor = [UIColor redColor];
        style.strokeWidth = 2.0;
        return style;
  } else {
        GMSMutableFeatureStyle *style = [GMSMutableFeatureStyle style];
        style.fillColor = [[UIColor greenColor] colorWithAlphaComponent:0.3];
        style.strokeColor = [UIColor greenColor];
        style.strokeWidth = 2.0;
        return style;
    }
  };

多段线数据的样式设置示例

本例演示了如何为基于多段线几何图形的数据地图项设置样式。

对表示多段线的地图项应用样式。

关于数据集

本例中使用的数据集显示 西雅图地区的桥梁。 以下内容摘录自 GeoJSON 数据集文件，显示了一个具有代表性的地图项条目。

{
  "type": "Feature",
  "properties": {
      "OBJECTID": 1,
      "COMPTYPE": 66,
      "COMPKEY": 515774,
      "HANSEGKEY": 489781,
      "UNITID": "BRG-935",
      "UNITTYPE": " ",
      "BRGUNITID": "BRG-935",
      "UNITDESC_BRG": "YALE AVE BR REV LANE OC                                                                                                                                                                                                                                        ",
      "UNITDESC_SEG": "HOWELL ST ON RP BETWEEN HOWELL ST AND I5 SB                                                                                                                                                                                                                    ",
      "INSTDATE": null,
      "EXPDATE": null,
      "STATUS": " ",
      "STATUSDT": null,
      "CONDITION": " ",
      "CONDDT": null,
      "OWN": " ",
      "LSTVERIFY": null,
      "MAINTBY": " ",
      "ADDBY": "GARCIAA",
      "ADDDTTM": "2010-01-21T00:00:00Z",
      "MODBY": null,
      "MODDTTM": null,
      "BR_NBR": 935,
      "BR_CODE": " 935",
      "BR_TYPE": "ST",
      "BR_NAME": "YALE AVE BR REV LANE OC",
      "BR_FACILITIES": "YALE AVE-SR 5 ON RAMP",
      "BR_FEATURES": "SR 5 REV LANE",
      "BR_RATING": 0,
      "BR_INSET": 1,
      "BR_GEO": "DT",
      "BR_OWNER": "DOT",
      "BR_OWNER_NAME": "State of Washington",
      "GEOBASID": 0,
      "XGEOBASID": 0,
      "GISSEGKEY": 489781,
      "EARTHQUAKE_RESPONSE_TEAM": " ",
      "SHAPE_Length": 220.11891836147655
  },
  "geometry": {
      "type": "LineString",
      "coordinates": [
          [
              -122.329201929090928,
              47.616910448708538
          ],
          [
              -122.329206483407461,
              47.616976719821004
          ],
          [
              -122.32921802149356,
              47.617042137515213
          ],
          [
              -122.329236413912909,
              47.617105967923777
          ],
          [
              -122.329261454336034,
              47.617167494985758
          ],
          [
              -122.329292861855023,
              47.617226028479571
          ],
          [
              -122.329330284134699,
              47.617280911766009
          ],
          [
              -122.329373301365223,
              47.617331529154569
          ],
          [
              -122.329421430971635,
              47.617377312810319
          ],
          [
              -122.329474133027375,
              47.617417749124023
          ],
          [
              -122.32953081631139,
              47.617452384473893
          ]
      ]
  }
},

设置多段线数据地图项的样式

以下代码段会将相同的样式直接应用于所有数据地图项。

Swift

// Define a style with green fill and stroke.
// Apply the style to the datasets features.
layer.style = { feature in
  let style = MutableFeatureStyle()
  style.fillColor = .green.withAlphaComponent(0.5);
  style.strokeColor = [UIColor greenColor];
  style.strokeWidth = 2.0;
  return style
}

Objective-C

// Define a style with green fill and stroke.
// Apply the style to the datasets features.
layer.style = ^(GMSDatasetFeature *feature) {
  GMSMutableFeatureStyle *style = [GMSMutableFeatureStyle style];
  style.fillColor = [[UIColor greenColor] colorWithAlphaComponent:0.5];
  style.strokeColor = [UIColor greenColor];
  style.strokeWidth = 2.0;
  return style;
};