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JavaScript Quickstart

Get started with A5 in JavaScript by installing the package and running a simple example.

Installation​

Install the A5 package using npm:

npm install a5-js

Or using yarn:

yarn add a5-js

Code Example: Generate A5 Cells​

Here's a complete example that generates A5 cells at a specified resolution and outputs them as GeoJSON:

import { cellToBoundary, bigIntToHex, cellToChildren } from "a5-js";

// Generate all cells at the specified resolution
const resolution = 2;
const cells = [];
const cellIds = cellToChildren(0n, resolution);

// Generate boundary for each cell
for (let cellId of cellIds) {
  const cellIdHex = bigIntToHex(cellId);
  const boundary = cellToBoundary(cellId);

  cells.push({
    type: "Feature",
    geometry: { type: "Polygon", coordinates: [boundary] },
    properties: { cellIdHex }
  });
}

// Create GeoJSON FeatureCollection
const geojson = { type: "FeatureCollection", features: cells };

Example Output​

The above code will produce a collection of cells that cover the whole world.

Note that the cells all have the same area (approximately) shape - they are just warped by the map projection

A5 Wireframe Example
Cells shown: 240
Hover over cells to see their IDs

CLI Usage​

The code above in CLI form is available here.

node index.js 2 a5.geojson

This will generate A5 cells at resolution 2 and save them as GeoJSON in a5.geojson.

Next Steps​