JavaScript.geo

function distance(from, to) {
    let R = 6371000;
    let dLat = (to.lat - from.lat).toRad();
    let dLon = (to.lon - from.lon).toRad();
    let lat1 = from.lat.toRad();
    let lat2 = to.lat.toRad();

    let a = Math.sin(dLat / 2) * Math.sin(dLat / 2) + Math.sin(dLon / 2) * Math.sin(dLon / 2) * Math.cos(lat1) * Math.cos(lat2);
    let c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));

    return R * c;
}

Number.prototype.toRad = function() {
    return this * Math.PI / 180;
}

function geo2polar(from, to) {
    let p = {};
    let x = to.lon - from.lon;
    let y = to.lat - from.lat;

    p.r     = Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2));
    p.theta = 0;

    if (x > 0 && y >= 0) {
        p.theta = Math.atan(y / x);
    } else if (x > 0 && y < 0) {
        p.theta = Math.atan(y / x) + 2 * Math.PI;
    } else if (x < 0) {
        p.theta = Math.atan(y / x) + Math.PI;
    } else if (x == 0 && y > 0) {
        p.theta = Math.PI / 2;
    } else if (x == 0 && y < 0) {
        p.theta = 3 * Math.PI / 2;
    } else if (x == 0 && y == 0) {
        p.theta = 0;
    }

    return p;
}