GCDistance(38.9333,-94.3253,38.9314,-94.4876) . "
\n";
// print "GCAzimuth: " . $oGC->GCAzimuth(38.9333,-94.3253,38.9314,-94.4876) . "
\n";
// print "ApproxDistance: " . $oGC->ApproxDistance(38.9333,-94.3253,38.9314,-94.4876) . "
\n";
// print "EllipsoidDistance: " . $oGC->EllipsoidDistance(38.80126649,-94.44590241,43.3368,-96.8755) . "
\n";
// print "EllipsoidDistance In Miles: " . ConvKilometersToMiles($oGC->EllipsoidDistance(38.80126649,-94.44590241,43.3368,-96.8755));
class GeoCalc {
var $PI = 3.14159265359;
var $TWOPI = 6.28318530718;
var $DE2RA = 0.01745329252;
var $RA2DE = 57.2957795129;
var $ERAD = 6378.135;
var $ERADM = 6378135.0;
var $AVG_ERAD = 6371.0;
var $EPS = 0.000000000005;
var $KM2MI = 0.621371;
var $FLATTENING = 0;
function GeoCalc() {
$this->FLATTENING = 1.0/298.26; // Earth flattening
// (WGS 1972)
return;
}
function GCDistance($lat1, $lon1, $lat2, $lon2) {
$lat1 *= $this->DE2RA;
$lon1 *= $this->DE2RA;
$lat2 *= $this->DE2RA;
$lon2 *= $this->DE2RA;
$d = sin($lat1)*sin($lat2) + cos($lat1)*cos($lat2)*cos($lon1 - $lon2);
return ($this->AVG_ERAD * acos($d));
}
function GCAzimuth($lat1, $lon1, $lat2, $lon2) {
$result = 0.0;
$ilat1 = intval(0.50 + $lat1 * 360000.0);
$ilat2 = intval(0.50 + $lat2 * 360000.0);
$ilon1 = intval(0.50 + $lon1 * 360000.0);
$ilon2 = intval(0.50 + $lon2 * 360000.0);
$lat1 *= $this->DE2RA;
$lon1 *= $this->DE2RA;
$lat2 *= $this->DE2RA;
$lon2 *= $this->DE2RA;
if (($ilat1 == $ilat2) && ($ilon1 == $ilon2)) {
return result;
}
else if ($ilat1 == $ilat2) {
if ($ilon1 > $ilon2)
$result = 90.0;
else
$result = 270.0;
}
else if ($ilon1 == $ilon2) {
if ($ilat1 > $ilat2)
$result = 180.0;
}
else {
$c = acos(sin($lat2)*sin($lat1) + cos($lat2)*cos($lat1)*cos(($lon2-$lon1)));
$A = asin(cos($lat2)*sin(($lon2-$lon1))/sin($c));
$result = ($A * $this->RA2DE);
if (($ilat2 > $ilat1) && ($ilon2 > $ilon1)) {
$result = $result;
}
else if (($ilat2 < $ilat1) && ($ilon2 < $ilon1)) {
$result = 180.0 - $result;
}
else if (($ilat2 < $ilat1) && ($ilon2 > $ilon1)) {
$result = 180.0 - $result;
}
else if (($ilat2 > $ilat1) && ($ilon2 < $ilon1)) {
$result += 360.0;
}
}
return $result;
}
function ApproxDistance($lat1, $lon1, $lat2, $lon2) {
$lat1 = $this->DE2RA * $lat1;
$lon1 = -$this->DE2RA * $lon1;
$lat2 = $this->DE2RA * $lat2;
$lon2 = -$this->DE2RA * $lon2;
$F = ($lat1 + $lat2) / 2.0;
$G = ($lat1 - $lat2) / 2.0;
$L = ($lon1 - $lon2) / 2.0;
$sing = sin($G);
$cosl = cos($L);
$cosf = cos($F);
$sinl = sin($L);
$sinf = sin($F);
$cosg = cos($G);
$S = $sing*$sing*$cosl*$cosl + $cosf*$cosf*$sinl*$sinl;
$C = $cosg*$cosg*$cosl*$cosl + $sinf*$sinf*$sinl*$sinl;
$W = atan2(sqrt($S),sqrt($C));
$R = sqrt(($S*$C))/$W;
$H1 = (3 * $R - 1.0) / (2.0 * $C);
$H2 = (3 * $R + 1.0) / (2.0 * $S);
$D = 2 * $W * $this->ERAD;
$return = ($D * (1 + $this->FLATTENING * $H1 * $sinf*$sinf*$cosg*$cosg - $this->FLATTENING*$H2*$cosf*$cosf*$sing*$sing));
return $return;
}
function EllipsoidDistance($lat1, $lon1, $lat2, $lon2) {
$distance = 0.0;
$faz = 0.0;
$baz = 0.0;
$r = 1.0 - $this->FLATTENING;
$tu1 = 0.0;
$tu2 = 0.0;
$cu1 = 0.0;
$su1 = 0.0;
$cu2 = 0.0;
$x = 0.0;
$sx = 0.0;
$cx = 0.0;
$sy = 0.0;
$cy = 0.0;
$y = 0.0;
$sa = 0.0;
$c2a = 0.0;
$cz = 0.0;
$e = 0.0;
$c = 0.0;
$d = 0.0;
$cosy1 = 0.0;
$cosy2 = 0.0;
if(($lon1 == $lon2) && ($lat1 == $lat2))
return $distance;
$lon1 *= $this->DE2RA;
$lon2 *= $this->DE2RA;
$lat1 *= $this->DE2RA;
$lat2 *= $this->DE2RA;
$cosy1 = cos($lat1);
$cosy2 = cos($lat2);
if($cosy1 == 0.0) $cosy1 = 0.0000000001;
if($cosy2 == 0.0) $cosy2 = 0.0000000001;
$tu1 = $r * sin($lat1) / $cosy1;
$tu2 = $r * sin($lat2) / $cosy2;
$cu1 = 1.0 / sqrt($tu1 * $tu1 + 1.0);
$su1 = $cu1 * $tu1;
$cu2 = 1.0 / sqrt($tu2 * $tu2 + 1.0);
$x = $lon2 - $lon1;
$distance = $cu1 * $cu2;
$baz = $distance * $tu2;
$faz = $baz * $tu1;
while(abs($d - $x) > $this->EPS) {
$sx = sin($x);
$cx = cos($x);
$tu1 = $cu2 * $sx;
$tu2 = $baz - $su1 * $cu2 * $cx;
$sy = sqrt($tu1 * $tu1 + $tu2 * $tu2);
$cy = $distance * $cx + $faz;
$y = atan2($sy, $cy);
$sa = $distance * $sx / $sy;
$c2a = - $sa * $sa + 1.0;
$cz = $faz + $faz;
if($c2a > 0.0) $cz = - $cz / $c2a + $cy;
$e = $cz * $cz * 2.0 - 1.0;
$c = ((-3.0 * $c2a + 4.0) * $this->FLATTENING + 4.0) * $c2a * $this->FLATTENING / 16.0;
$d = $x;
$x = (($e * $cy * $c + $cz) * $sy * $c + $y) * $sa;
$x = (1.0 - $c) * $x * $this->FLATTENING + $lon2 - $lon1;
}
$x = sqrt((1.0 / $r / $r - 1.0) * $c2a + 1.0) + 1.0;
$x = ($x - 2.0) / $x;
$c = 1.0 - $x;
$c = ($x * $x / 4.0 + 1.0) / $c;
$d = (0.375 * $x * $x - 1.0) * $x;
$x = $e * $cy;
$distance = 1.0 - $e - $e;
$distance = (((($sy * $sy * 4.0 - 3.0) * $distance * $cz * $d / 6.0 - $x) * $d / 4.0 + $cz) * $sy * $d + $y) * $c * $this->ERAD * $r;
return $distance;
}
function getKmPerLonAtLat($dLatitude) {
// Thanks to Eric Iverson for this correction! Must convert degrees to radians...
$dLatitude *= $this->DE2RA;
return 111.321 * cos($dLatitude);
}
function getLonPerKmAtLat($dLatitude) {
return 1 / $this->getKmPerLonAtLat($dLatitude);
}
function getKmPerLat() {
return 111.000;
}
function getLatPerKm() {
return 1 / $this->getKmPerLat();
}
}
function ConvKilometersToMiles($dValue) {
return $dValue / 1.609344;
}
?>