function isLatitude(latitude) {
    return (
        latitude != undefined && isFinite(latitude) && Math.abs(latitude) <= 90
    );
}

function isLongitude(longitude) {
    return (
        longitude != undefined &&
        isFinite(longitude) &&
        Math.abs(longitude) <= 180
    );
}

function checkValidCoordinations(coordinations) {
    if (isLatitude(coordinations[0]) && isLongitude(coordinations[1])) {
        return true;
    } else {
        setError(coordinations);
    }
}

function setError(coordinations) {
    alert("Coordinations " + coordinations + " are not valid.");
}

function countAzimuth(lat1, lng1, lat2, lng2) {
    // Convert to radians
    const lat1Rad = (lat1 * Math.PI) / 180;
    const lon1Rad = (lng1 * Math.PI) / 180;
    const lat2Rad = (lat2 * Math.PI) / 180;
    const lon2Rad = (lng2 * Math.PI) / 180;
    // Azimuth Calculation
    const y = Math.sin(lon2Rad - lon1Rad) * Math.cos(lat2Rad);
    const x =
        Math.cos(lat1Rad) * Math.sin(lat2Rad) -
        Math.sin(lat1Rad) * Math.cos(lat2Rad) * Math.cos(lon2Rad - lon1Rad);
    // Convert to degrees
    let angle = (Math.atan2(y, x) * 180) / Math.PI;
    // Normalize to 0-360 degrees
    angle = Math.round(((angle + 360) % 360) - 90);

    return angle;
}