Custom Projection
This demo illustrates how to implement a custom projection. To do it, set the aspectRatio, to, and from properties. The Wagner-VI projection is used in this example.
www.wikipedia.org
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import React from 'react';
import VectorMap, {
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(coordinates) {
const x = coordinates[0] * RADIANS;
const y = Math.min(Math.max(coordinates[1] * 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(coordinates) {
const x = coordinates[0];
const y = Math.min(Math.max(coordinates[1], -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,
];
},
};
export default function App() {
return (
<VectorMap
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>
</VectorMap>
);
}
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/22.2.6/css/dx.light.css" />
<link rel="stylesheet" type="text/css" href="styles.css" />
<script src="https://unpkg.com/core-js@2.6.12/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]],
},
});
}
window.config = {
transpiler: 'plugin-babel',
meta: {
'devextreme/localization.js': {
'esModule': true,
},
'devextreme/dist/js/vectormap-data/*': {
'esModule': true,
},
},
paths: {
'npm:': 'https://unpkg.com/',
},
defaultExtension: 'js',
map: {
'react': 'npm:react@17.0.2/umd/react.development.js',
'react-dom': 'npm:react-dom@17.0.2/umd/react-dom.development.js',
'prop-types': 'npm:prop-types@15.8.1/prop-types.js',
'devextreme/dist/js/vectormap-data': 'js/vectormap-data',
'rrule': 'npm:rrule@2.6.4/dist/es5/rrule.js',
'luxon': 'npm:luxon@1.28.0/build/global/luxon.min.js',
'es6-object-assign': 'npm:es6-object-assign@1.1.0',
'devextreme': 'npm:devextreme@22.2.6/cjs',
'devextreme-react': 'npm:devextreme-react@22.2.6',
'jszip': 'npm:jszip@3.7.1/dist/jszip.min.js',
'devextreme-quill': 'npm:devextreme-quill@1.5.20/dist/dx-quill.min.js',
'devexpress-diagram': 'npm:devexpress-diagram@2.1.72/dist/dx-diagram.js',
'devexpress-gantt': 'npm:devexpress-gantt@4.1.43/dist/dx-gantt.js',
'@devextreme/runtime': 'npm:@devextreme/runtime@3.0.11',
'inferno': 'npm:inferno@7.4.11/dist/inferno.min.js',
'inferno-compat': 'npm:inferno-compat/dist/inferno-compat.min.js',
'inferno-create-element': 'npm:inferno-create-element@7.4.11/dist/inferno-create-element.min.js',
'inferno-dom': 'npm:inferno-dom/dist/inferno-dom.min.js',
'inferno-hydrate': 'npm:inferno-hydrate@7.4.11/dist/inferno-hydrate.min.js',
'inferno-clone-vnode': 'npm:inferno-clone-vnode/dist/inferno-clone-vnode.min.js',
'inferno-create-class': 'npm:inferno-create-class/dist/inferno-create-class.min.js',
'inferno-extras': 'npm:inferno-extras/dist/inferno-extras.min.js',
// SystemJS plugins
'plugin-babel': 'npm:systemjs-plugin-babel@0.0.25/plugin-babel.js',
'systemjs-babel-build': 'npm:systemjs-plugin-babel@0.0.25/systemjs-babel-browser.js',
// Prettier
'prettier/standalone': 'npm:prettier@2.8.4/standalone.js',
'prettier/parser-html': 'npm:prettier@2.8.4/parser-html.js',
},
packages: {
'devextreme': {
defaultExtension: 'js',
},
'devextreme-react': {
main: 'index.js',
},
'devextreme/events/utils': {
main: 'index',
},
'devextreme/events': {
main: 'index',
},
'es6-object-assign': {
main: './index.js',
defaultExtension: 'js',
},
},
packageConfigPaths: [
'npm:@devextreme/*/package.json',
'npm:@devextreme/runtime@3.0.11/inferno/package.json',
],
babelOptions: {
sourceMaps: false,
stage0: true,
react: true,
},
};
System.config(window.config);