heatmap - how to generate random Lat-lng values with known center and radius in javascript? - Stack Overflow

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i want to create a heatmap layer over a 100 meters radius and so i want to generate random lat-long values in that specific radius and so want to replace it with

 var taxiData = [
{location: new google.maps.LatLng(41.8819, -87.6278),weight: 2},
{location: new google.maps.LatLng(41.8820, -87.6279),weight: 1},
 new google.maps.LatLng(41.8821, -87.6280),
{location: new google.maps.LatLng(41.8822, -87.6281),weight: 2},
{location: new google.maps.LatLng(41.8823, -87.6282),weight: 5},
{location: new google.maps.LatLng(41.8824, -87.6283),weight: 3},
];

please help

i want to create a heatmap layer over a 100 meters radius and so i want to generate random lat-long values in that specific radius and so want to replace it with

 var taxiData = [
{location: new google.maps.LatLng(41.8819, -87.6278),weight: 2},
{location: new google.maps.LatLng(41.8820, -87.6279),weight: 1},
 new google.maps.LatLng(41.8821, -87.6280),
{location: new google.maps.LatLng(41.8822, -87.6281),weight: 2},
{location: new google.maps.LatLng(41.8823, -87.6282),weight: 5},
{location: new google.maps.LatLng(41.8824, -87.6283),weight: 3},
];

please help

• javascript
• heatmap

Share Improve this question Follow asked Aug 17, 2014 at 15:44 nish soninish soni 4111 silver badge33 bronze badges

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1 Answer 1

Sorted by: Reset to default 10

This should allow you to do that.

What the code does:

First we generate a fairly uniform random point within a triangle and convert that to a point within the circle of a radius. Then we convert that point to offset coordinates and add them to the original.

An object containing two values latitude and longitude is returned.

var getRandomLocation = function (latitude, longitude, radiusInMeters) {

    var getRandomCoordinates = function (radius, uniform) {
        // Generate two random numbers
        var a = Math.random(),
            b = Math.random();

        // Flip for more uniformity.
        if (uniform) {
            if (b < a) {
                var c = b;
                b = a;
                a = c;
            }
        }

        // It's all triangles.
        return [
            b * radius * Math.cos(2 * Math.PI * a / b),
            b * radius * Math.sin(2 * Math.PI * a / b)
        ];
    };

    var randomCoordinates = getRandomCoordinates(radiusInMeters, true);

    // Earths radius in meters via WGS 84 model.
    var earth = 6378137;

    // Offsets in meters.
    var northOffset = randomCoordinates[0],
        eastOffset = randomCoordinates[1];

    // Offset coordinates in radians.
    var offsetLatitude = northOffset / earth,
        offsetLongitude = eastOffset / (earth * Math.cos(Math.PI * (latitude / 180)));

    // Offset position in decimal degrees.
    return {
        latitude: latitude + (offsetLatitude * (180 / Math.PI)),
        longitude: longitude + (offsetLongitude * (180 / Math.PI))
    }
};

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