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带有比例尺控件的 OpenStreetMap 重投影

发布于 2022-11-30 23:36:05 字数 3561 浏览 0 评论 0 收藏 0

这个例子显示了OpenStreetMap到NAD83 Indiana East的客户端再投影。

这个例子显示了OpenStreetMap到NAD83 Indiana East的客户端再投影，包括一个带有美国单位的ScaleLine控件。本示例展示客户端从 OpenStreetMap 到 NAD83 Indiana East的重投影，包括一个美国单位的比例尺控件。

main.js

import 'ol/ol.css';
import Map from 'ol/Map';
import OSM from 'ol/source/OSM';
import TileLayer from 'ol/layer/Tile';
import View from 'ol/View';
import proj4 from 'proj4';
import {ScaleLine} from 'ol/control';
import {fromLonLat, transformExtent} from 'ol/proj';
import {register} from 'ol/proj/proj4';

proj4.defs(
  'Indiana-East',
  'PROJCS["IN83-EF",GEOGCS["LL83",DATUM["NAD83",' +
    'SPHEROID["GRS1980",6378137.000,298.25722210]],PRIMEM["Greenwich",0],' +
    'UNIT["Degree",0.017453292519943295]],PROJECTION["Transverse_Mercator"],' +
    'PARAMETER["false_easting",328083.333],' +
    'PARAMETER["false_northing",820208.333],' +
    'PARAMETER["scale_factor",0.999966666667],' +
    'PARAMETER["central_meridian",-85.66666666666670],' +
    'PARAMETER["latitude_of_origin",37.50000000000000],' +
    'UNIT["Foot_US",0.30480060960122]]'
);
register(proj4);

const map = new Map({
  layers: [
    new TileLayer({
      source: new OSM(),
    }),
  ],
  target: 'map',
  view: new View({
    projection: 'Indiana-East',
    center: fromLonLat([-85.685, 39.891], 'Indiana-East'),
    zoom: 7,
    extent: transformExtent(
      [-172.54, 23.81, -47.74, 86.46],
      'EPSG:4326',
      'Indiana-East'
    ),
    minZoom: 6,
  }),
});

map.addControl(new ScaleLine({units: 'us'}));

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>OpenStreetMap Reprojection with ScaleLine Control</title>
    <!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
    <script src="https://unpkg.com/elm-pep"></script>
    <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
    <script src="https://cdn.polyfill.io/v3/polyfill.min.js?features=fetch,requestAnimationFrame,Element.prototype.classList,URL,TextDecoder,Number.isInteger"></script>
    <style>
      .map {
        width: 100%;
        height:400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <script src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "scaleline-indiana-east",
  "dependencies": {
    "ol": "7.1.0",
    "proj4": "^2.7.5"
  },
  "devDependencies": {
    "parcel": "^2.0.0-beta.1"
  },
  "scripts": {
    "start": "parcel index.html",
    "build": "parcel build --public-url . index.html"
  }
}

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