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Vector Map

Custom Projection

This demo illustrates how to implement a custom projection. To do it, set the aspectRatio, to, and from options. The Wagner-VI projection is used in this example.

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import React from 'react'; import Map, { Layer, Export } from 'devextreme-react/vector-map'; import * as mapsData from 'devextreme/dist/js/vectormap-data/world.js'; import { coordLinesData } from './data.js'; const RADIANS = Math.PI / 180; const WAGNER_6_P_LAT = Math.PI / Math.sqrt(3); const WAGNER_6_U_LAT = 2 / Math.sqrt(3) - 0.1; const customProjection = { aspectRatio: 2, to([l, lt]) { const x = l * RADIANS; const y = Math.min(Math.max(lt * RADIANS, -WAGNER_6_P_LAT), +WAGNER_6_P_LAT); const t = y / Math.PI; return [ x / Math.PI * Math.sqrt(1 - 3 * t * t), y * 2 / Math.PI ]; }, from([x, y]) { y = Math.min(Math.max(y, -WAGNER_6_U_LAT), +WAGNER_6_U_LAT); const t = y / 2; return [ x * Math.PI / Math.sqrt(1 - 3 * t * t) / RADIANS, y * Math.PI / 2 / RADIANS ]; } }; const App = function() { return ( <Map id={'vector-map'} projection={customProjection} title={'Wagner VI projection'} > <Layer dataSource={mapsData.world} /> <Layer dataSource={coordLinesData} color={'#aaa'} borderWidth={1} hoverEanbled={false} /> <Export enabled={true}></Export> </Map> ); }; export default App;
import React from 'react'; import ReactDOM from 'react-dom'; import App from './App.js'; ReactDOM.render( <App />, document.getElementById('app') );
<!DOCTYPE html> <html> <head> <title>DevExtreme Demo</title> <meta http-equiv="X-UA-Compatible" content="IE=edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0" /> <link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/19.2.3/css/dx.common.css" /> <link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/19.2.3/css/dx.light.css" /> <link rel="stylesheet" type="text/css" href="styles.css" /> <script src="https://unpkg.com/core-js@2.4.1/client/shim.min.js"></script> <script src="https://unpkg.com/systemjs@0.21.3/dist/system.js"></script> <script type="text/javascript" src="config.js"></script> <script type="text/javascript"> System.import('./index.js'); </script> </head> <body class="dx-viewport"> <div class="demo-container"> <div id="app"></div> </div> </body> </html>
#vector-map { height: 400px; }
export const coordLinesData = { type: 'FeatureCollection', features: [] }; //add meridians for (let longitude = -180; longitude <= 180; longitude += 30) { const lineCoords = []; for (let latitude = -90; latitude <= 90; latitude += 5) { lineCoords.push([longitude, latitude]); } coordLinesData.features.push({ geometry: { type: 'LineString', coordinates: lineCoords } }); } //add parallels for (let latitude = -90; latitude <= 90; latitude += 30) { coordLinesData.features.push({ geometry: { type: 'LineString', coordinates: [[ -180, latitude ], [ 180, latitude]] } }); }
System.config({ transpiler: 'plugin-babel', meta: { 'devextreme/dist/js/vectormap-data/*': { esModule: true } }, paths: { 'npm:': 'https://unpkg.com/' }, defaultExtension: 'js', map: { 'react': 'npm:react@16/umd/react.development.js', 'react-dom': 'npm:react-dom@16/umd/react-dom.development.js', 'prop-types': 'npm:prop-types/prop-types.js', 'devextreme': 'npm:devextreme@19.2', 'devextreme/dist/js/vectormap-data': 'npm:devextreme@19.2/dist/js/vectormap-data', 'devextreme-react': 'npm:devextreme-react@19.2', 'jszip': 'npm:jszip@3.1.3/dist/jszip.min.js', 'quill': 'npm:quill@1.3.7/dist/quill.js', 'devexpress-diagram': 'npm:devexpress-diagram', 'devexpress-gantt': 'npm:devexpress-gantt', // SystemJS plugins 'plugin-babel': 'npm:systemjs-plugin-babel@0/plugin-babel.js', 'systemjs-babel-build': 'npm:systemjs-plugin-babel@0/systemjs-babel-browser.js' }, packages: { 'devextreme': { defaultExtension: 'js' }, 'devextreme-react': { main: 'index.js' } }, babelOptions: { sourceMaps: false, stage0: true, react: true } });