/* M_PI//pi greco float sin ( float arg )//arg in radianti float cos ( float arg ) float atan ( float arg ) float sqrt ( float arg ) float pow ( float base, float esp ) double round ( double val [, int precisione] ) */ If(isset($_POST['calcola'])){ $lat1=$_POST['unonord']; $lon1=$_POST['unoest']; $lat2=$_POST['duenord']; $lon2=$_POST['dueest']; $lat1r=$lat1 * M_PI/180; $lon1r=$lon1 * M_PI/180; $lat2r=$lat2 * M_PI/180; $lon2r=$lon2 * M_PI/180; $cosarc = sin($lat1r) * sin($lat2r) + cos($lat1r) * cos($lat2r) * cos($lon2r - $lon1r); $sinarc = sqrt(1-pow($cosarc,2)); $arc_r= atan($sinarc/$cosarc);//radians $arc_d = $arc_r * 180/M_PI;//degrees $primi=$arc_d*60; $distkm= round($primi*1.853,3);//in km $distm=$distkm*1000; //1'= 1 nautical mile = 1.853 km --> dist comes out in kilometers } ?>