Angular 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

<dx-vector-map id="vector-map" [projection]="customProjection" title="Wagner VI projection" > <dxo-vector-map-export [enabled]="true"></dxo-vector-map-export> <dxi-vector-map-layer [dataSource]="worldMap"></dxi-vector-map-layer> <dxi-vector-map-layer [dataSource]="coordLinesData" [hoverEnabled]="false" [borderWidth]="1" color="#aaa" ></dxi-vector-map-layer> </dx-vector-map>

import { bootstrapApplication } from '@angular/platform-browser'; import { Component, enableProdMode, provideZoneChangeDetection } from '@angular/core'; import { DxVectorMapModule } from 'devextreme-angular'; import * as mapsData from 'devextreme-dist/js/vectormap-data/world.js'; import { FeatureCollection, Service } from './app.service'; 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; if (!/localhost/.test(document.location.host)) { enableProdMode(); } @Component({ selector: 'demo-app', providers: [Service], templateUrl: './app.component.html', styleUrls: ['./app.component.css'], imports: [ DxVectorMapModule, ], }) export class AppComponent { worldMap = mapsData.world; customProjection = { aspectRatio: 2, to(coordinates: 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[]) { 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, ]; }, }; coordLinesData: FeatureCollection; constructor(service: Service) { this.coordLinesData = service.getCoordLinesData(); } } bootstrapApplication(AppComponent, { providers: [ provideZoneChangeDetection({ eventCoalescing: true, runCoalescing: true }), ], });

::ng-deep #vector-map { height: 400px; }

import { Injectable } from '@angular/core'; export class FeatureCollection { type: string; features: Feature[]; } export class Feature { geometry: FeatureGeometry; } export class FeatureGeometry { type: string; coordinates: number[][]; } const coordLinesData: FeatureCollection = { 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]], }, }); } @Injectable() export class Service { getCoordLinesData(): FeatureCollection { return coordLinesData; } }

<!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" /> <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script> <script>window.jQuery || document.write(decodeURIComponent('%3Cscript src="js/jquery.min.js"%3E%3C/script%3E'))</script> </head> <body class="dx-viewport"> <div class="demo-container"> <demo-app>Loading...</demo-app> </div> <script src="https://cdn.jsdelivr.net/npm/zone.js@0.16.2/bundles/zone.umd.js"></script> <script src="./bundle.js" type="module"></script> </body> </html>