Sphere Mollweide

graticule 3 Mollweide 1 projection 13 proj4js 6

Example of a Sphere Mollweide map with a Graticule layer.

main.js

import GeoJSON from 'ol/format/GeoJSON.js';
import Graticule from 'ol/layer/Graticule.js';
import Map from 'ol/Map.js';
import Projection from 'ol/proj/Projection.js';
import VectorLayer from 'ol/layer/Vector.js';
import VectorSource from 'ol/source/Vector.js';
import View from 'ol/View.js';
import proj4 from 'proj4';
import {register} from 'ol/proj/proj4.js';

proj4.defs(
  'ESRI:53009',
  '+proj=moll +lon_0=0 +x_0=0 +y_0=0 +a=6371000 ' +
    '+b=6371000 +units=m +no_defs',
);
register(proj4);

// Configure the Sphere Mollweide projection object with an extent,
// and a world extent. These are required for the Graticule.
const sphereMollweideProjection = new Projection({
  code: 'ESRI:53009',
  extent: [
    -18019909.21177587, -9009954.605703328, 18019909.21177587,
    9009954.605703328,
  ],
  worldExtent: [-179, -89.99, 179, 89.99],
});

const map = new Map({
  keyboardEventTarget: document,
  layers: [
    new VectorLayer({
      source: new VectorSource({
        url: 'https://openlayers.org/data/vector/ecoregions.json',
        format: new GeoJSON(),
      }),
      style: {
        'fill-color': ['string', ['get', 'COLOR_BIO'], '#eee'],
      },
    }),
    new Graticule(),
  ],
  target: 'map',
  view: new View({
    center: [0, 0],
    projection: sphereMollweideProjection,
    zoom: 2,
  }),
});

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Sphere Mollweide</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>

    <script type="module" src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "sphere-mollweide",
  "dependencies": {
    "ol": "10.2.1",
    "proj4": "2.12.1"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}