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Diffstat (limited to 'includes/phpcoord/phpcoord-2.3.php')
| -rw-r--r-- | includes/phpcoord/phpcoord-2.3.php | 785 |
1 files changed, 785 insertions, 0 deletions
diff --git a/includes/phpcoord/phpcoord-2.3.php b/includes/phpcoord/phpcoord-2.3.php new file mode 100644 index 0000000..edac27a --- /dev/null +++ b/includes/phpcoord/phpcoord-2.3.php @@ -0,0 +1,785 @@ +<?php + +/**-------------------------------------------------------------------------- + * PHPcoord + * phpcoord.php + * + * @package kernel + */ + + // (c) 2005 Jonathan Stott + // + // Created on 11-Aug-2005 + // + // 2.3 - 24 Aug 2006 + // - Changed OSRef->toSixFigureString() so that the eastings and northings + // are rounded rather than floored. + // 2.2 - 11 Feb 2006 + // - Used different algorithm for calculating distance between latitudes + // and longitudes - fixes a number of problems with distance calculations + // 2.1 - 22 Dec 2005 + // - Added getOSRefFromSixFigureReference function + // 2.0 - 21 Dec 2005 + // - Completely different object design - conversion functions now through + // objects rather than static functions + // - Updated comments and documentation + // 1.1 - 11 Sep 2005 + // - Added OSGB36/WGS84 data conversions + // 1.0 - 11 Aug 2005 + // - Initial version + //-------------------------------------------------------------------------- + + +/** + * LatLng + * + * @package kernel + */ + class LatLng { + + var $lat; + var $lng; + + + /** + * Create a new LatLng object from the given latitude and longitude + * + * @param lat latitude + * @param lng longitude + */ + function LatLng($lat, $lng) { + $this->lat = $lat; + $this->lng = $lng; + } + + + /** + * Return a string representation of this LatLng object + * + * @return a string representation of this LatLng object + */ + function toString() { + return "(" . $this->lat . ", " . $this->lng . ")"; + } + + + /** + * Calculate the surface distance between this LatLng object and the one + * passed in as a parameter. + * + * @param to a LatLng object to measure the surface distance to + * @return the surface distance + */ + function distance($to) { + $er = 6366.707; + + $latFrom = deg2rad($this->lat); + $latTo = deg2rad($to->lat); + $lngFrom = deg2rad($this->lng); + $lngTo = deg2rad($to->lng); + + $x1 = $er * cos($lngFrom) * sin($latFrom); + $y1 = $er * sin($lngFrom) * sin($latFrom); + $z1 = $er * cos($latFrom); + + $x2 = $er * cos($lngTo) * sin($latTo); + $y2 = $er * sin($lngTo) * sin($latTo); + $z2 = $er * cos($latTo); + + $d = acos(sin($latFrom)*sin($latTo) + cos($latFrom)*cos($latTo)*cos($lngTo-$lngFrom)) * $er; + + return $d; + } + + + /** + * Convert this LatLng object from OSGB36 datum to WGS84 datum. + */ + function OSGB36ToWGS84() { + $airy1830 = new RefEll(6377563.396, 6356256.909); + $a = $airy1830->maj; + $b = $airy1830->min; + $eSquared = $airy1830->ecc; + $phi = deg2rad($this->lat); + $lambda = deg2rad($this->lng); + $v = $a / (sqrt(1 - $eSquared * sinSquared($phi))); + $H = 0; // height + $x = ($v + $H) * cos($phi) * cos($lambda); + $y = ($v + $H) * cos($phi) * sin($lambda); + $z = ((1 - $eSquared) * $v + $H) * sin($phi); + + $tx = 446.448; + $ty = -124.157; + $tz = 542.060; + $s = -0.0000204894; + $rx = deg2rad( 0.00004172222); + $ry = deg2rad( 0.00006861111); + $rz = deg2rad( 0.00023391666); + + $xB = $tx + ($x * (1 + $s)) + (-$rx * $y) + ($ry * $z); + $yB = $ty + ($rz * $x) + ($y * (1 + $s)) + (-$rx * $z); + $zB = $tz + (-$ry * $x) + ($rx * $y) + ($z * (1 + $s)); + + $wgs84 = new RefEll(6378137.000, 6356752.3141); + $a = $wgs84->maj; + $b = $wgs84->min; + $eSquared = $wgs84->ecc; + + $lambdaB = rad2deg(atan($yB / $xB)); + $p = sqrt(($xB * $xB) + ($yB * $yB)); + $phiN = atan($zB / ($p * (1 - $eSquared))); + for ($i = 1; $i < 10; $i++) { + $v = $a / (sqrt(1 - $eSquared * sinSquared($phiN))); + $phiN1 = atan(($zB + ($eSquared * $v * sin($phiN))) / $p); + $phiN = $phiN1; + } + + $phiB = rad2deg($phiN); + + $this->lat = $phiB; + $this->lng = $lambdaB; + } + + + /** + * Convert this LatLng object from WGS84 datum to OSGB36 datum. + */ + function WGS84ToOSGB36() { + $wgs84 = new RefEll(6378137.000, 6356752.3141); + $a = $wgs84->maj; + $b = $wgs84->min; + $eSquared = $wgs84->ecc; + $phi = deg2rad($this->lat); + $lambda = deg2rad($this->lng); + $v = $a / (sqrt(1 - $eSquared * sinSquared($phi))); + $H = 0; // height + $x = ($v + $H) * cos($phi) * cos($lambda); + $y = ($v + $H) * cos($phi) * sin($lambda); + $z = ((1 - $eSquared) * $v + $H) * sin($phi); + + $tx = -446.448; + $ty = 124.157; + $tz = -542.060; + $s = 0.0000204894; + $rx = deg2rad(-0.00004172222); + $ry = deg2rad(-0.00006861111); + $rz = deg2rad(-0.00023391666); + + $xB = $tx + ($x * (1 + $s)) + (-$rx * $y) + ($ry * $z); + $yB = $ty + ($rz * $x) + ($y * (1 + $s)) + (-$rx * $z); + $zB = $tz + (-$ry * $x) + ($rx * $y) + ($z * (1 + $s)); + + $airy1830 = new RefEll(6377563.396, 6356256.909); + $a = $airy1830->maj; + $b = $airy1830->min; + $eSquared = $airy1830->ecc; + + $lambdaB = rad2deg(atan($yB / $xB)); + $p = sqrt(($xB * $xB) + ($yB * $yB)); + $phiN = atan($zB / ($p * (1 - $eSquared))); + for ($i = 1; $i < 10; $i++) { + $v = $a / (sqrt(1 - $eSquared * sinSquared($phiN))); + $phiN1 = atan(($zB + ($eSquared * $v * sin($phiN))) / $p); + $phiN = $phiN1; + } + + $phiB = rad2deg($phiN); + + $this->lat = $phiB; + $this->lng = $lambdaB; + } + + + /** + * Convert this LatLng object into an OSGB grid reference. Note that this + * function does not take into account the bounds of the OSGB grid - + * beyond the bounds of the OSGB grid, the resulting OSRef object has no + * meaning + * + * @return the converted OSGB grid reference + */ + function toOSRef() { + $airy1830 = new RefEll(6377563.396, 6356256.909); + $OSGB_F0 = 0.9996012717; + $N0 = -100000.0; + $E0 = 400000.0; + $phi0 = deg2rad(49.0); + $lambda0 = deg2rad(-2.0); + $a = $airy1830->maj; + $b = $airy1830->min; + $eSquared = $airy1830->ecc; + $phi = deg2rad($this->lat); + $lambda = deg2rad($this->lng); + $E = 0.0; + $N = 0.0; + $n = ($a - $b) / ($a + $b); + $v = $a * $OSGB_F0 * pow(1.0 - $eSquared * sinSquared($phi), -0.5); + $rho = + $a * $OSGB_F0 * (1.0 - $eSquared) * pow(1.0 - $eSquared * sinSquared($phi), -1.5); + $etaSquared = ($v / $rho) - 1.0; + $M = + ($b * $OSGB_F0) + * (((1 + $n + ((5.0 / 4.0) * $n * $n) + ((5.0 / 4.0) * $n * $n * $n)) + * ($phi - $phi0)) + - (((3 * $n) + (3 * $n * $n) + ((21.0 / 8.0) * $n * $n * $n)) + * sin($phi - $phi0) + * cos($phi + $phi0)) + + ((((15.0 / 8.0) * $n * $n) + ((15.0 / 8.0) * $n * $n * $n)) + * sin(2.0 * ($phi - $phi0)) + * cos(2.0 * ($phi + $phi0))) + - (((35.0 / 24.0) * $n * $n * $n) + * sin(3.0 * ($phi - $phi0)) + * cos(3.0 * ($phi + $phi0)))); + $I = $M + $N0; + $II = ($v / 2.0) * sin($phi) * cos($phi); + $III = + ($v / 24.0) + * sin($phi) + * pow(cos($phi), 3.0) + * (5.0 - tanSquared($phi) + (9.0 * $etaSquared)); + $IIIA = + ($v / 720.0) + * sin($phi) + * pow(cos($phi), 5.0) + * (61.0 - (58.0 * tanSquared($phi)) + pow(tan($phi), 4.0)); + $IV = $v * cos($phi); + $V = ($v / 6.0) * pow(cos($phi), 3.0) * (($v / $rho) - tanSquared($phi)); + $VI = + ($v / 120.0) + * pow(cos($phi), 5.0) + * (5.0 + - (18.0 * tanSquared($phi)) + + (pow(tan($phi), 4.0)) + + (14 * $etaSquared) + - (58 * tanSquared($phi) * $etaSquared)); + + $N = + $I + + ($II * pow($lambda - $lambda0, 2.0)) + + ($III * pow($lambda - $lambda0, 4.0)) + + ($IIIA * pow($lambda - $lambda0, 6.0)); + $E = + $E0 + + ($IV * ($lambda - $lambda0)) + + ($V * pow($lambda - $lambda0, 3.0)) + + ($VI * pow($lambda - $lambda0, 5.0)); + + return new OSRef($E, $N); + } + + + /** + * Convert a latitude and longitude to an UTM reference + * + * @return the converted UTM reference + */ + function toUTMRef() { + $wgs84 = new RefEll(6378137, 6356752.314); + $UTM_F0 = 0.9996; + $a = $wgs84->maj; + $eSquared = $wgs84->ecc; + $longitude = $this->lng; + $latitude = $this->lat; + + $latitudeRad = $latitude * (pi() / 180.0); + $longitudeRad = $longitude * (pi() / 180.0); + $longitudeZone = (int) (($longitude + 180.0) / 6.0) + 1; + + // Special zone for Norway + if ($latitude >= 56.0 + && $latitude < 64.0 + && $longitude >= 3.0 + && $longitude < 12.0) { + $longitudeZone = 32; + } + + // Special zones for Svalbard + if ($latitude >= 72.0 && $latitude < 84.0) { + if ($longitude >= 0.0 && $longitude < 9.0) { + $longitudeZone = 31; + } else if ($longitude >= 9.0 && $longitude < 21.0) { + $longitudeZone = 33; + } else if ($longitude >= 21.0 && $longitude < 33.0) { + $longitudeZone = 35; + } else if ($longitude >= 33.0 && $longitude < 42.0) { + $longitudeZone = 37; + } + } + + $longitudeOrigin = ($longitudeZone - 1) * 6 - 180 + 3; + $longitudeOriginRad = $longitudeOrigin * (pi() / 180.0); + + $UTMZone = getUTMLatitudeZoneLetter($latitude); + + $ePrimeSquared = ($eSquared) / (1 - $eSquared); + + $n = $a / sqrt(1 - $eSquared * sin($latitudeRad) * sin($latitudeRad)); + $t = tan($latitudeRad) * tan($latitudeRad); + $c = $ePrimeSquared * cos($latitudeRad) * cos($latitudeRad); + $A = cos($latitudeRad) * ($longitudeRad - $longitudeOriginRad); + + $M = + $a + * ((1 + - $eSquared / 4 + - 3 * $eSquared * $eSquared / 64 + - 5 * $eSquared * $eSquared * $eSquared / 256) + * $latitudeRad + - (3 * $eSquared / 8 + + 3 * $eSquared * $eSquared / 32 + + 45 * $eSquared * $eSquared * $eSquared / 1024) + * sin(2 * $latitudeRad) + + (15 * $eSquared * $eSquared / 256 + + 45 * $eSquared * $eSquared * $eSquared / 1024) + * sin(4 * $latitudeRad) + - (35 * $eSquared * $eSquared * $eSquared / 3072) + * sin(6 * $latitudeRad)); + + $UTMEasting = + (double) ($UTM_F0 + * $n + * ($A + + (1 - $t + $c) * pow($A, 3.0) / 6 + + (5 - 18 * $t + $t * $t + 72 * $c - 58 * $ePrimeSquared) + * pow($A, 5.0) + / 120) + + 500000.0); + + $UTMNorthing = + (double) ($UTM_F0 + * ($M + + $n + * tan($latitudeRad) + * ($A * $A / 2 + + (5 - $t + (9 * $c) + (4 * $c * $c)) * pow($A, 4.0) / 24 + + (61 - (58 * $t) + ($t * $t) + (600 * $c) - (330 * $ePrimeSquared)) + * pow($A, 6.0) + / 720))); + + // Adjust for the southern hemisphere + if ($latitude < 0) { + $UTMNorthing += 10000000.0; + } + + return new UTMRef($UTMEasting, $UTMNorthing, $UTMZone, $longitudeZone); + } + } + +/** + * OSRef + * References given with OSRef are accurate to 1m. + * + * @package kernel + */ + class OSRef { + + var $easting; + var $northing; + + + /** + * Create a new OSRef object representing an OSGB grid reference. Note + * that the parameters for this constructor require eastings and + * northings with 1m accuracy and need to be absolute with respect to + * the whole of the British Grid. For example, to create an OSRef + * object from the six-figure grid reference TG514131, the easting would + * be 651400 and the northing would be 313100. + * + * Grid references with accuracy greater than 1m can be represented + * using floating point values for the easting and northing. For example, + * a value representing an easting or northing accurate to 1mm would be + * given as 651400.0001. + * + * @param easting the easting of the reference (with 1m accuracy) + * @param northing the northing of the reference (with 1m accuracy) + */ + function OSRef($easting, $northing) { + $this->easting = $easting; + $this->northing = $northing; + } + + + /** + * Convert this grid reference into a string showing the exact values + * of the easting and northing. + * + * @return + */ + function toString() { + return "(" . $this->easting . ", " . $this->northing . ")"; + } + + + /** + * Convert this grid reference into a string using a standard six-figure + * grid reference including the two-character designation for the 100km + * square. e.g. TG514131. + * + * @return + */ + function toSixFigureString() { + $hundredkmE = floor($this->easting / 100000); + $hundredkmN = floor($this->northing / 100000); + $firstLetter = ""; + if ($hundredkmN < 5) { + if ($hundredkmE < 5) { + $firstLetter = "S"; + } else { + $firstLetter = "T"; + } + } else if ($hundredkmN < 10) { + if ($hundredkmE < 5) { + $firstLetter = "N"; + } else { + $firstLetter = "O"; + } + } else { + $firstLetter = "H"; + } + + $secondLetter = ""; + $index = 65 + ((4 - ($hundredkmN % 5)) * 5) + ($hundredkmE % 5); + $ti = $index; + if ($index >= 73) $index++; + $secondLetter = chr($index); + + $e = round(($this->easting - (100000 * $hundredkmE)) / 100); + $n = round(($this->northing - (100000 * $hundredkmN)) / 100); + + return sprintf("%s%s%03d%03d", $firstLetter, $secondLetter, $e, $n); + } + + + /** + * Convert this grid reference into a latitude and longitude + * + * @return + */ + function toLatLng() { + $airy1830 = new RefEll(6377563.396, 6356256.909); + $OSGB_F0 = 0.9996012717; + $N0 = -100050.0; + $E0 = 400110.0; + $phi0 = deg2rad(49.0); + $lambda0 = deg2rad(-2.0); + $a = $airy1830->maj; + $b = $airy1830->min; + $eSquared = $airy1830->ecc; + $phi = 0.0; + $lambda = 0.0; + $E = $this->easting; + $N = $this->northing; + $n = ($a - $b) / ($a + $b); + $M = 0.0; + $phiPrime = (($N - $N0) / ($a * $OSGB_F0)) + $phi0; + do { + $M = + ($b * $OSGB_F0) + * (((1 + $n + ((5.0 / 4.0) * $n * $n) + ((5.0 / 4.0) * $n * $n * $n)) + * ($phiPrime - $phi0)) + - (((3 * $n) + (3 * $n * $n) + ((21.0 / 8.0) * $n * $n * $n)) + * sin($phiPrime - $phi0) + * cos($phiPrime + $phi0)) + + ((((15.0 / 8.0) * $n * $n) + ((15.0 / 8.0) * $n * $n * $n)) + * sin(2.0 * ($phiPrime - $phi0)) + * cos(2.0 * ($phiPrime + $phi0))) + - (((35.0 / 24.0) * $n * $n * $n) + * sin(3.0 * ($phiPrime - $phi0)) + * cos(3.0 * ($phiPrime + $phi0)))); + $phiPrime += ($N - $N0 - $M) / ($a * $OSGB_F0); + } while (($N - $N0 - $M) >= 0.001); + $v = $a * $OSGB_F0 * pow(1.0 - $eSquared * sinSquared($phiPrime), -0.5); + $rho = + $a + * $OSGB_F0 + * (1.0 - $eSquared) + * pow(1.0 - $eSquared * sinSquared($phiPrime), -1.5); + $etaSquared = ($v / $rho) - 1.0; + $VII = tan($phiPrime) / (2 * $rho * $v); + $VIII = + (tan($phiPrime) / (24.0 * $rho * pow($v, 3.0))) + * (5.0 + + (3.0 * tanSquared($phiPrime)) + + $etaSquared + - (9.0 * tanSquared($phiPrime) * $etaSquared)); + $IX = + (tan($phiPrime) / (720.0 * $rho * pow($v, 5.0))) + * (61.0 + + (90.0 * tanSquared($phiPrime)) + + (45.0 * tanSquared($phiPrime) * tanSquared($phiPrime))); + $X = sec($phiPrime) / $v; + $XI = + (sec($phiPrime) / (6.0 * $v * $v * $v)) + * (($v / $rho) + (2 * tanSquared($phiPrime))); + $XII = + (sec($phiPrime) / (120.0 * pow($v, 5.0))) + * (5.0 + + (28.0 * tanSquared($phiPrime)) + + (24.0 * tanSquared($phiPrime) * tanSquared($phiPrime))); + $XIIA = + (sec($phiPrime) / (5040.0 * pow($v, 7.0))) + * (61.0 + + (662.0 * tanSquared($phiPrime)) + + (1320.0 * tanSquared($phiPrime) * tanSquared($phiPrime)) + + (720.0 + * tanSquared($phiPrime) + * tanSquared($phiPrime) + * tanSquared($phiPrime))); + $phi = + $phiPrime + - ($VII * pow($E - $E0, 2.0)) + + ($VIII * pow($E - $E0, 4.0)) + - ($IX * pow($E - $E0, 6.0)); + $lambda = + $lambda0 + + ($X * ($E - $E0)) + - ($XI * pow($E - $E0, 3.0)) + + ($XII * pow($E - $E0, 5.0)) + - ($XIIA * pow($E - $E0, 7.0)); + + return new LatLng(rad2deg($phi), rad2deg($lambda)); + } + } + +/** + * UTMRef + * + * @package kernel + */ + class UTMRef { + + var $easting; + var $northing; + var $latZone; + var $lngZone; + + + /** + * Create a new object representing a UTM reference. + * + * @param easting + * @param northing + * @param latZone + * @param lngZone + */ + function UTMRef($easting, $northing, $latZone, $lngZone) { + $this->easting = $easting; + $this->northing = $northing; + $this->latZone = $latZone; + $this->lngZone = $lngZone; + } + + + /** + * Return a string representation of this UTM reference + * + * @return + */ + function toString() { + return $this->lngZone . $this->latZone . " " . + $this->easting . " " . $this->northing; + } + + + /** + * Convert this UTM reference to a latitude and longitude + * + * @return the converted latitude and longitude + */ + function toLatLng() { + $wgs84 = new RefEll(6378137, 6356752.314); + $UTM_F0 = 0.9996; + $a = $wgs84->maj; + $eSquared = $wgs84->ecc; + $ePrimeSquared = $eSquared / (1.0 - $eSquared); + $e1 = (1 - sqrt(1 - $eSquared)) / (1 + sqrt(1 - $eSquared)); + $x = $this->easting - 500000.0;; + $y = $this->northing; + $zoneNumber = $this->lngZone; + $zoneLetter = $this->latZone; + + $longitudeOrigin = ($zoneNumber - 1.0) * 6.0 - 180.0 + 3.0; + + // Correct y for southern hemisphere + if ((ord($zoneLetter) - ord("N")) < 0) { + $y -= 10000000.0; + } + + $m = $y / $UTM_F0; + $mu = + $m + / ($a + * (1.0 + - $eSquared / 4.0 + - 3.0 * $eSquared * $eSquared / 64.0 + - 5.0 + * pow($eSquared, 3.0) + / 256.0)); + + $phi1Rad = + $mu + + (3.0 * $e1 / 2.0 - 27.0 * pow($e1, 3.0) / 32.0) * sin(2.0 * $mu) + + (21.0 * $e1 * $e1 / 16.0 - 55.0 * pow($e1, 4.0) / 32.0) + * sin(4.0 * $mu) + + (151.0 * pow($e1, 3.0) / 96.0) * sin(6.0 * $mu); + + $n = + $a + / sqrt(1.0 - $eSquared * sin($phi1Rad) * sin($phi1Rad)); + $t = tan($phi1Rad) * tan($phi1Rad); + $c = $ePrimeSquared * cos($phi1Rad) * cos($phi1Rad); + $r = + $a + * (1.0 - $eSquared) + / pow( + 1.0 - $eSquared * sin($phi1Rad) * sin($phi1Rad), + 1.5); + $d = $x / ($n * $UTM_F0); + + $latitude = ( + $phi1Rad + - ($n * tan($phi1Rad) / $r) + * ($d * $d / 2.0 + - (5.0 + + (3.0 * $t) + + (10.0 * $c) + - (4.0 * $c * $c) + - (9.0 * $ePrimeSquared)) + * pow($d, 4.0) + / 24.0 + + (61.0 + + (90.0 * $t) + + (298.0 * $c) + + (45.0 * $t * $t) + - (252.0 * $ePrimeSquared) + - (3.0 * $c * $c)) + * pow($d, 6.0) + / 720.0)) * (180.0 / pi()); + + $longitude = $longitudeOrigin + ( + ($d + - (1.0 + 2.0 * $t + $c) * pow($d, 3.0) / 6.0 + + (5.0 + - (2.0 * $c) + + (28.0 * $t) + - (3.0 * $c * $c) + + (8.0 * $ePrimeSquared) + + (24.0 * $t * $t)) + * pow($d, 5.0) + / 120.0) + / cos($phi1Rad)) * (180.0 / pi()); + + return new LatLng($latitude, $longitude); + } + } + +/** + * RefEll + * + * @package kernel + */ + class RefEll { + + var $maj; + var $min; + var $ecc; + + + /** + * Create a new RefEll object to represent a reference ellipsoid + * + * @param maj the major axis + * @param min the minor axis + */ + function RefEll($maj, $min) { + $this->maj = $maj; + $this->min = $min; + $this->ecc = (($maj * $maj) - ($min * $min)) / ($maj * $maj); + } + } + + + // ================================================== Mathematical Functions + + function sinSquared($x) { + return sin($x) * sin($x); + } + + function cosSquared($x) { + return cos($x) * cos($x); + } + + function tanSquared($x) { + return tan($x) * tan($x); + } + + function sec($x) { + return 1.0 / cos($x); + } + + + /** + * Take a string formatted as a six-figure OS grid reference (e.g. + * "TG514131") and return a reference to an OSRef object that represents + * that grid reference. The first character must be H, N, S, O or T. + * The second character can be any uppercase character from A through Z + * excluding I. + * + * @param ref + * @return + * @since 2.1 + */ + function getOSRefFromSixFigureReference($ref) { + $char1 = substr($ref, 0, 1); + $char2 = substr($ref, 1, 1); + $east = substr($ref, 2, 3) * 100; + $north = substr($ref, 5, 3) * 100; + if ($char1 == 'H') { + $north += 1000000; + } else if ($char1 == 'N') { + $north += 500000; + } else if ($char1 == 'O') { + $north += 500000; + $east += 500000; + } else if ($char1 == 'T') { + $east += 500000; + } + $char2ord = ord($char2); + if ($char2ord > 73) $char2ord--; // Adjust for no I + $nx = (($char2ord - 65) % 5) * 100000; + $ny = (4 - floor(($char2ord - 65) / 5)) * 100000; + return new OSRef($east + $nx, $north + $ny); + } + + + /** + * Work out the UTM latitude zone from the latitude + * + * @param latitude + * @return + */ + function getUTMLatitudeZoneLetter($latitude) { + if ((84 >= $latitude) && ($latitude >= 72)) return "X"; + else if (( 72 > $latitude) && ($latitude >= 64)) return "W"; + else if (( 64 > $latitude) && ($latitude >= 56)) return "V"; + else if (( 56 > $latitude) && ($latitude >= 48)) return "U"; + else if (( 48 > $latitude) && ($latitude >= 40)) return "T"; + else if (( 40 > $latitude) && ($latitude >= 32)) return "S"; + else if (( 32 > $latitude) && ($latitude >= 24)) return "R"; + else if (( 24 > $latitude) && ($latitude >= 16)) return "Q"; + else if (( 16 > $latitude) && ($latitude >= 8)) return "P"; + else if (( 8 > $latitude) && ($latitude >= 0)) return "N"; + else if (( 0 > $latitude) && ($latitude >= -8)) return "M"; + else if (( -8 > $latitude) && ($latitude >= -16)) return "L"; + else if ((-16 > $latitude) && ($latitude >= -24)) return "K"; + else if ((-24 > $latitude) && ($latitude >= -32)) return "J"; + else if ((-32 > $latitude) && ($latitude >= -40)) return "H"; + else if ((-40 > $latitude) && ($latitude >= -48)) return "G"; + else if ((-48 > $latitude) && ($latitude >= -56)) return "F"; + else if ((-56 > $latitude) && ($latitude >= -64)) return "E"; + else if ((-64 > $latitude) && ($latitude >= -72)) return "D"; + else if ((-72 > $latitude) && ($latitude >= -80)) return "C"; + else return 'Z'; + } + +?> |