PHP Session variable checking is not working - php

Question

Here is my issue I'm a bigger in PHP I have done a login page and it is working perfectly in my local machine But after uploading to Server its not working.
Session is created but redirection is not happening.
here is my code and any help is really appreciated.
if( isset($_POST['btn-login'])) {
$username = $_POST['username'];
$password = $_POST['password'];
include 'connection.php';
$sql="SELECT * FROM user WHERE name = '$username' AND password = sha1('$password') AND status = '1'";
$result = mysql_query($sql);
$result = mysql_fetch_array($result);
$userId = '';
if( $result) {
$userId = $result['id'];
$_SESSION['userId'] = $userId;
if( $userId == 1) {
header("location:map.php");
} else if( $userId == 2){
header("location:admin/map-settings.php");
} else {
echo "<li class='loginError'>There is an Error in Login Please Contact Administrator</li>";
}
} else {
echo "<li class='loginError'>Invalid Username or Password</li>";
}

Answer 1

make sure to print_r($_SESSION)
If it did not give empty array, then your session is set.
now make sure nothing in your code started output before you set the "Location" header.
and you could use this to redirect your page
if (!headers_sent())
$filename="map.php";
header('Location: '.$filename);
else {
echo '<script type="text/javascript">';
echo 'window.location.href="'.$filename.'";';
echo '</script>';
echo '<noscript>';
echo '<meta http-equiv="refresh" content="0;url='.$filename.'" />';
echo '</noscript>';
}