ArcGIS API for JavaScript：对geometry、Graphic、FeatureLayer的理解

geometry：几何

应该就是几何的意思

AMD:
require(["esri/geometry"], (geometry) => { /* code goes here */ });
ESM:
import * as geometry from "@arcgis/core/geometry";

Graphic：图形

图形Graphic是现实世界地理现象的矢量表示。它可以包含几何geometry、符号symbol和属性attributes。图形将显示在图形层 GraphicsLayer中。

// geometry：几何
let polyline = {  
  type: "polyline",  // autocasts as new Polyline()
    paths: [
      [-111.30, 52.68],
      [-98, 49.5],
      [-93.94, 29.89]
    ]
};
// 符号symbol
let polylineSymbol = {
  type: "simple-line",  // autocasts as SimpleLineSymbol()
  color: [226, 119, 40],
  width: 4
};
// 属性attributes
let polylineAtt = {
  Name: "Keystone Pipeline",
  Owner: "TransCanada"
};
//  Graphic：图形
let polylineGraphic = new Graphic({
  geometry: polyline, // geometry：几何
  symbol: polylineSymbol,
  attributes: polylineAtt
});

view.graphics.add(polylineGraphic);

FeatureLayer：要素图层

AMD：
require(["esri/layers/FeatureLayer"], (FeatureLayer) => { /* code goes here */ });
ESM：
import FeatureLayer from "@arcgis/core/layers/FeatureLayer";

空间图层由离散要素组成，每个要素都有一个几何体Geometry，允许在 2D MapView 或 3D SceneView 中将其渲染为具有空间上下文的Graphic。

// Create featurelayer from client-side graphics
//从graphics图形创建featurelayer要素图层
const layer = new FeatureLayer({
  // graphics图形
  source: graphics,
  fields: [{
    name: "ObjectID",
    alias: "ObjectID",
    type: "oid"
  }, {
    name: "place",
    alias: "Place",
    type: "string"
  }],
  objectIdField: "ObjectID",
  geometryType: "point"
});