Geographic coordinates to 2D x% and y% coords

mercator_projection

function getCoordinates($lat, $lng){
    $mapWidth = 1000; // change this value
    $mapHeight = 1000; // change this value
    $pi = pi();

    // get x value
    $c['x'] = ($lng+180)*($mapWidth/360);

    // convert from degrees to radians
    $latRad = $lat*$pi/180;

    // get y value
    $mercN = log(tan(($pi/4)+($latRad/2)));
    $c['y'] = ($mapHeight/2)-($mapWidth*$mercN/(2*$pi));

    // x and y to x% and y%
    $c['x'] = (100*$c['x'])/$mapWidth;
    $c['y'] = (100*$c['y'])/$mapHeight;

    return $c;
}