Vue Vector Map - 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

Backend API

<template> <DxVectorMap id="vector-map" :projection="customProjection" title="Wagner VI projection" > <DxLayer :data-source="world" /> <DxLayer :data-source="coordLinesData" :hover-enabled="false" :border-width="1" color="#aaa" /> <DxExport :enabled="true"/> </DxVectorMap> </template> <script setup lang="ts"> import { DxVectorMap, DxLayer, DxExport, } from 'devextreme-vue/vector-map'; // @ts-ignore import * as mapsData from 'devextreme-dist/js/vectormap-data/world.js'; import { coordLinesData } from './data.ts'; const world = mapsData.world; 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: [number, number]) { 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: [number, number]) { 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, ]; }, }; </script> <style> #vector-map { height: 400px; } </style>

export const coordLinesData: { type: string; features: { geometry: { type: string; coordinates: number[][]; }; }[]; } = { type: 'FeatureCollection', features: [], }; // add meridians for (let longitude = -180; longitude <= 180; longitude += 30) { const lineCoords: number[][] = []; 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]], }, }); }

import { createApp } from 'vue'; import App from './App.vue'; createApp(App).mount('#app');

<!DOCTYPE html> <html lang="en"> <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=5.0" /> <link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/26.1.5/css/dx.light.css" /> <link rel="stylesheet" type="text/css" href="./bundle.css" /> </head> <body class="dx-viewport"> <div class="demo-container"> <div id="app"></div> </div> <script src="bundles/vendor/vue.vendor.js"></script> <script src="./bundle.js"></script> </body> </html>