数据驱动的拉伸

此示例演示如何应用大小可视变量以基于数字字段值以主题方式拉伸要素。使用连续的尺寸渐变以主题方式可视化要素主题中审查的尺寸视觉变量的相同基本原则也适用于 3D 主题可视化。

但是，在使用诸如 ExtrudeSymbol3DLayer ， PathSymbol3DLayer 和 ObjectSymbol3DLayer 等体积符号图层时，大小值始终以实际单位（米）表示。

const renderer = {
  type: "simple", // autocasts as new SimpleRenderer()
  symbol: {
    type: "polygon-3d", // autocasts as new PolygonSymbol3D()
    symbolLayers: [{ type: "extrude" }] // autocasts as new ExtrudeSymbol3DLayer()
  },
  label: "% population in poverty by county",
  visualVariables: [
    {
      type: "size", // indicates this is a size visual variable
      field: "POP_POVERTY", // total population in poverty
      normalizationField: "TOTPOP_CY", // total population
      stops: [
        {
          value: 0.1, // features where < 10% of the pop in poverty
          size: 10000 // will be extruded by this height in meters
        },
        {
          value: 0.5, // features where > 50% of the pop in poverty
          size: 500000 // will be extruded by this height in meters
        }
      ]
    },
    {
      type: "color",
      field: "POP_POVERTY",
      normalizationField: "TOTPOP_CY",
      stops: [
        {
          value: 0.1,
          color: "#FFFCD4"
        },
        {
          value: 0.35,
          color: [153, 83, 41]
        }
      ]
    }
  ]
};