修改图形要素（Features）

使用 modify 交互编辑图形要素.

本示例演示综合使用 modify 和 select 交互。放大到感兴趣的区域选中一个图形要素进行编辑。拖动想要修改图形要素边界的点。你也可以在编辑之前选中多个图形要素一起进行编辑拓扑（按住Shift+单机鼠标 来选中多个图形要素）。

main.js

import GeoJSON from 'ol/format/GeoJSON.js';
import Map from 'ol/Map.js';
import VectorLayer from 'ol/layer/Vector.js';
import VectorSource from 'ol/source/Vector.js';
import View from 'ol/View.js';
import {
  Modify,
  Select,
  defaults as defaultInteractions,
} from 'ol/interaction.js';
import {fromLonLat} from 'ol/proj.js';

const vector = new VectorLayer({
  background: 'white',
  source: new VectorSource({
    url: 'https://openlayers.org/data/vector/us-states.json',
    format: new GeoJSON(),
    wrapX: false,
  }),
});

const select = new Select({
  wrapX: false,
});

const modify = new Modify({
  features: select.getFeatures(),
});

const map = new Map({
  interactions: defaultInteractions().extend([select, modify]),
  layers: [vector],
  target: 'map',
  view: new View({
    center: fromLonLat([-100, 38.5]),
    zoom: 4,
  }),
});

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Modify Features</title>
    <link rel="stylesheet" href="node_modules/ol/ol.css">
    <style>
      .map {
        width: 100%;
        height: 400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
    <script src="./resources/elm-pep.js"></script>
    <script type="module" src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "modify-features",
  "dependencies": {
    "ol": "7.3.0"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}