function CalculateArc($Text) {
global $TempArea,$TempPoint,$CenterY, $CenterX,$Rotation ;
$parts=split(",",substr($Text,3) );
if ( count($parts)==1 ) { echo "Wrong format in CalculateArc<BR>"; return; }
list ($res, $StartLon , $StartLat) = ReadCoords( $parts[0] );
list ($res, $EndLon , $EndLat) = ReadCoords( $parts[1] );
list($Radius, $StartBearing) = DistanceBearing($CenterY, $CenterX, $StartLat, $StartLon, 1,1);
list($tmp1 , $EndBearing) = DistanceBearing($CenterY, $CenterX, $EndLat, $EndLon,0,1);
$TempPoint->Latitude = $StartLat;
$TempPoint->Longitude = $StartLon;
AddPoint($TempPoint);
while(abs($EndBearing-$StartBearing) > 7.5) {
$StartBearing += $Rotation *5 ;
if($StartBearing > 360)
$StartBearing -= 360;
if($StartBearing < 0)
$StartBearing += 360;
list($TempPoint->Latitude,$TempPoint->Longitude)= FindLatitudeLongitude($CenterY, $CenterX, $StartBearing, $Radius, 1,1 );
AddPoint($TempPoint);
}
$TempPoint->Latitude = $EndLat;
$TempPoint->Longitude = $EndLon;
AddPoint($TempPoint);
}
function CrossTrackError($lon1, $lat1, $lon2, $lat2, $lon3, $lat3)
{
$dot1 = dot($lon1, $lat1, $lon2, $lat2, $lon3, $lat3);
if ($dot1 > 0) {
list($dist_BD, $tmp1) = DistanceBearing($lat2, $lon2, $lat3, $lon3, 1, 0);
return $dist_BD;
}
$dot2 = dot($lon2, $lat2, $lon1, $lat1, $lon3, $lat3);
if ($dot2 > 0) {
list($dist_AD, $crs_AD) = DistanceBearing($lat1, $lon1, $lat3, $lon3, 1, 1);
return $dist_AD;
}
list($dist_AD, $crs_AD) = DistanceBearing($lat1, $lon1, $lat3, $lon3, 1, 1);
$dist_AD /= RAD_TO_DEG * 111194.9267;
$crs_AD *= DEG_TO_RAD;
// list($dist_AB, $crs_AB)= DistanceBearing($lat1, $lon1, $lat2, $lon2, 1,1);
list($tmp1, $crs_AB) = DistanceBearing($lat1, $lon1, $lat2, $lon2, 0, 1);
// DEBUG("a1",1,"dist_AB : $dist_AB dist_AD:$dist_AD ");
//$dist_AB_m= $dist_AB;
//$dist_AB/= (RAD_TO_DEG * 111194.9267);
$crs_AB *= DEG_TO_RAD;
// $lat1 *= DEG_TO_RAD;
// $lat2 *= DEG_TO_RAD;
// $lat3 *= DEG_TO_RAD;
// $lon1 *= DEG_TO_RAD;
// $lon2 *= DEG_TO_RAD;
// $lon3 *= DEG_TO_RAD;
// double XTD; // cross track distance
// double ATD; // along track distance
// The "along track distance", ATD, the distance from A along the
// course towards B to the point abeam D
$sindist_AD = sin($dist_AD);
$XTD = asin($sindist_AD * sin($crs_AD - $crs_AB));
//$sinXTD = sin($XTD);
//$ATD = asin(sqrt( $sindist_AD*$sindist_AD - $sinXTD*$sinXTD )/cos($XTD));
/*
if (lon4 && lat4) {
IntermediatePoint(lon1, lat1, lon2, lat2, ATD, dist_AB,
lon4, lat4);
}
*/
// units
$XTD *= RAD_TO_DEG * 111194.9267;
//$ATD *= (RAD_TO_DEG * 111194.9267);
/*
//DEBUG("a1",1," XTD: $XTD , ATD: $ATD<BR>");
if ($ATD > $dist_AB_m ) {
list($dist_BD, $tmp1 )= DistanceBearing($lat2, $lon2, $lat3, $lon3, 1,0);
$XTD = min($dist_AD_m ,$dist_BD);
DEBUG("a1",1," special case: $dist_AD_m , $dist_BD<BR>");
} else {
DEBUG("a1",1,"XTD ($XTD) is ok ($ATD < $dist_AB_m )<BR>");
}
*/
// return abs($ATD);
return abs($XTD);
}
