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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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<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>
import {
DxVectorMap,
DxLayer,
DxExport,
} from 'devextreme-vue/vector-map';
import { coordLinesData } from './data.js';
import * as mapsData from 'devextreme/dist/js/vectormap-data/world.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;
export default {
components: {
DxVectorMap,
DxLayer,
DxExport
},
data() {
return {
coordLinesData,
world: mapsData.world,
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
];
}
}
};
}
};
</script>
<style>
#vector-map {
height: 400px;
}
</style>
import { createApp } from 'vue';
import App from './App.vue';
createApp(App).mount('#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/20.2.4/css/dx.common.css" />
<link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/20.2.4/css/dx.light.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>
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: {
'*.vue': {
loader: 'vue-loader'
},
'devextreme/dist/js/vectormap-data/*': {
'esModule': true
},
},
paths: {
'npm:': 'https://unpkg.com/'
},
map: {
'vue': 'npm:vue@3.0.0/dist/vue.esm-browser.js',
'vue-loader': 'npm:dx-systemjs-vue-browser@1.0.15/index.js',
'devextreme/dist/js/vectormap-data': 'js/vectormap-data',
'mitt': 'npm:mitt/dist/mitt.umd.js',
'rrule': 'npm:rrule@2.6.6/dist/es5/rrule.js',
'luxon': 'npm:luxon@1.25.0/build/global/luxon.min.js',
'es6-object-assign': 'npm:es6-object-assign@1.1.0',
'devextreme': 'npm:devextreme@20.2.4',
'devextreme-vue': 'npm:devextreme-vue@20.2.4',
'jszip': 'npm:jszip@3.5.0/dist/jszip.min.js',
'devextreme-quill': 'npm:devextreme-quill@0.9.7/dist/dx-quill.min.js',
'devexpress-diagram': 'npm:devexpress-diagram@2.0.5/dist/dx-diagram.js',
'devexpress-gantt': 'npm:devexpress-gantt@2.0.8/dist/dx-gantt.js',
'preact': 'npm:preact@10.5.7/dist/preact.js',
'preact/hooks': 'npm:preact@10.5.7/hooks/dist/hooks.js',
'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'
},
packages: {
'devextreme-vue': {
main: 'index.js'
},
'devextreme': {
defaultExtension: 'js'
},
'devextreme/events/utils': {
main: 'index'
},
'devextreme/events': {
main: 'index'
},
'es6-object-assign': {
main: './index.js',
defaultExtension: 'js'
}
},
babelOptions: {
sourceMaps: false,
stage0: true
}
});