Synthetic Lines

Synthetic lines example.

main.js

import Feature from 'ol/Feature.js';
import LineString from 'ol/geom/LineString.js';
import Map from 'ol/Map.js';
import VectorLayer from 'ol/layer/Vector.js';
import VectorSource from 'ol/source/Vector.js';
import View from 'ol/View.js';
import {Stroke, Style} from 'ol/style.js';

const count = 10000;
const features = new Array(count);

let startPoint = [0, 0];
let endPoint;

let delta, deltaX, deltaY;
let signX = 1;
let signY = -1;

// Create a square spiral.
let i;
for (i = 0; i < count; ++i) {
  delta = (i + 1) * 2500;
  if (i % 2 === 0) {
    signY *= -1;
  } else {
    signX *= -1;
  }
  deltaX = delta * signX;
  deltaY = delta * signY;
  endPoint = [startPoint[0] + deltaX, startPoint[1] + deltaY];
  features[i] = new Feature({
    'geometry': new LineString([startPoint, endPoint]),
  });
  startPoint = endPoint;
}

const vector = new VectorLayer({
  source: new VectorSource({
    features: features,
    wrapX: false,
  }),
  style: new Style({
    stroke: new Stroke({
      color: '#666666',
      width: 1,
    }),
  }),
});

const view = new View({
  center: [0, 0],
  zoom: 0,
});

const map = new Map({
  layers: [vector],
  target: 'map',
  view: view,
});

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Synthetic Lines</title>
    <link rel="stylesheet" href="node_modules/ol/ol.css">
    <style>
      .map {
        width: 100%;
        height: 400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>

    <script type="module" src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "synthetic-lines",
  "dependencies": {
    "ol": "9.1.0"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}