geo.js

/**
* Generates number of random geolocation points given a center and a radius.
* @param  {Object} center A JS object with lat and lng attributes.
* @param  {number} radius Radius in meters.
* @param {number} count Number of points to generate.
* @return {array} Array of Objects with lat and lng attributes.
*/
function generateRandomPoints(center, radius, count) {
    var points = [];
    for (var i = 0; i < count; i++) {
        points.push(generateRandomPoint(center, radius));
    }
    return points;
}

/**
* Generates number of random GeoJson points given a center and a radius.
* @param  {Object} center A JS object with lat and lng attributes.
* @param  {number} radius Radius in meters.
* @param {number} count Number of points to generate.
* @return {array} Array of Objects with lat and lng attributes.
*/
function generateRandomGeoJsonPoints(center, radius, count) {
    const points = [];
    for (let i = 0; i < count; i++) {
        let point = generateRandomPoint(center, radius);
        let geoPoint = {
            "type" : "Point",
            "coordinates" : [
                point.lng,
                point.lat
            ]
        }
        points.push(geoPoint);
    }
    return points;
}


/**
* Generates number of random geolocation points given a center and a radius.
* Reference URL: http://goo.gl/KWcPE.
* @param  {Object} center A JS object with lat and lng attributes.
* @param  {number} radius Radius in meters.
* @return {Object} The generated random points as JS object with lat and lng attributes.
*/
function generateRandomPoint(center, radius) {
    var x0 = center.lng;
    var y0 = center.lat;
    // Convert Radius from meters to degrees.
    var rd = radius / 111300;

    var u = Math.random();
    var v = Math.random();

    var w = rd * Math.sqrt(u);
    var t = 2 * Math.PI * v;
    var x = w * Math.cos(t);
    var y = w * Math.sin(t);

    var xp = x / Math.cos(y0);

    // Resulting point.
    return { 'lat': y + y0, 'lng': xp + x0 };
}
exports.generateRandomPoints = generateRandomPoints;
exports.generateRandomGeoJsonPoints = generateRandomGeoJsonPoints