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0,0 → 1,534 |
<?php |
/*------------------------------------------------------------------------------ |
** File: gPoint.php |
** Description: PHP class to convert Latitude & Longitude coordinates into |
** UTM & Lambert Conic Conformal Northing/Easting coordinates. |
** Version: 1.3 |
** Author: Brenor Brophy |
** Email: brenor dot brophy at gmail dot com |
** Homepage: brenorbrophy.com |
**------------------------------------------------------------------------------ |
** COPYRIGHT (c) 2005, 2006, 2007, 2008 BRENOR BROPHY |
** |
** The source code included in this package is free software; you can |
** redistribute it and/or modify it under the terms of the GNU General Public |
** License as published by the Free Software Foundation. This license can be |
** read at: |
** |
** http://www.opensource.org/licenses/gpl-license.php |
** |
** This program is distributed in the hope that it will be useful, but WITHOUT |
** ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
** FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. |
**------------------------------------------------------------------------------ |
** |
** Code for datum and UTM conversion was converted from C++ code written by |
** Chuck Gantz (chuck dot gantz at globalstar dot com) from |
** http://www.gpsy.com/gpsinfo/geotoutm/ This URL has many other references to |
** useful information concerning conversion of coordinates. |
** |
** Rev History |
** ----------------------------------------------------------------------------- |
** 1.0 08/25/2005 Initial Release |
** 1.1 05/15/2006 Added software license language to header comments |
** Fixed an error in the convertTMtoLL() method. The latitude |
** calculation had a bunch of variables without $ symbols. |
** Fixed an error in convertLLtoTM() method, The $this-> was |
** missing in front of a couple of variables. Thanks to Bob |
** Robins of Maryland for catching the bugs. |
** 1.2 05/18/2007 Added default of NULL to $LongOrigin arguement in convertTMtoLL() |
** and convertLLtoTM() to eliminate warning messages when the |
** methods are called without a value for $LongOrigin. |
** 1.3 02/21/2008 Fixed a bug in the distanceFrom method, where the input parameters |
** were not being converted to radians prior to calculating the |
** distance. Thanks to Enrico Benco for finding pointing it out. |
*/ |
define ("meter2nm", (1/1852)); |
define ("nm2meter", 1852); |
|
/*------------------------------------------------------------------------------ |
** class gPoint ... for Geographic Point |
** |
** This class encapsulates the methods for representing a geographic point on the |
** earth in three different coordinate systema. Lat/Long, UTM and Lambert Conic |
** Conformal. |
*/ |
class gPoint |
{ |
/* Reference ellipsoids derived from Peter H. Dana's website- |
** http://www.colorado.edu/geography/gcraft/notes/datum/datum_f.html |
** email: pdana@pdana.com, web page: www.pdana.com |
** |
** Source: |
** Defense Mapping Agency. 1987b. DMA Technical Report: Supplement to Department |
** of Defense World Geodetic System 1984 Technical Report. Part I and II. |
** Washington, DC: Defense Mapping Agency |
*/ |
var $ellipsoid = array(//Ellipsoid name, Equatorial Radius, square of eccentricity |
"Airy" =>array (6377563, 0.00667054), |
"Australian National" =>array (6378160, 0.006694542), |
"Bessel 1841" =>array (6377397, 0.006674372), |
"Bessel 1841 Nambia" =>array (6377484, 0.006674372), |
"Clarke 1866" =>array (6378206, 0.006768658), |
"Clarke 1880" =>array (6378249, 0.006803511), |
"Everest" =>array (6377276, 0.006637847), |
"Fischer 1960 Mercury" =>array (6378166, 0.006693422), |
"Fischer 1968" =>array (6378150, 0.006693422), |
"GRS 1967" =>array (6378160, 0.006694605), |
"GRS 1980" =>array (6378137, 0.00669438), |
"Helmert 1906" =>array (6378200, 0.006693422), |
"Hough" =>array (6378270, 0.00672267), |
"International" =>array (6378388, 0.00672267), |
"Krassovsky" =>array (6378245, 0.006693422), |
"Modified Airy" =>array (6377340, 0.00667054), |
"Modified Everest" =>array (6377304, 0.006637847), |
"Modified Fischer 1960" =>array (6378155, 0.006693422), |
"South American 1969" =>array (6378160, 0.006694542), |
"WGS 60" =>array (6378165, 0.006693422), |
"WGS 66" =>array (6378145, 0.006694542), |
"WGS 72" =>array (6378135, 0.006694318), |
"WGS 84" =>array (6378137, 0.00669438)); |
|
// Properties |
var $a; // Equatorial Radius |
var $e2; // Square of eccentricity |
var $datum; // Selected datum |
var $Xp, $Yp; // X,Y pixel location |
var $lat, $long; // Latitude & Longitude of the point |
var $utmNorthing, $utmEasting, $utmZone; // UTM Coordinates of the point |
var $lccNorthing, $lccEasting; // Lambert coordinates of the point |
var $falseNorthing, $falseEasting; // Origin coordinates for Lambert Projection |
var $latOfOrigin; // For Lambert Projection |
var $longOfOrigin; // For Lambert Projection |
var $firstStdParallel; // For lambert Projection |
var $secondStdParallel; // For lambert Projection |
|
// constructor |
function gPoint($datum='WGS 84') // Default datum is WGS 84 |
{ |
$this->a = $this->ellipsoid[$datum][0]; // Set datum Equatorial Radius |
$this->e2 = $this->ellipsoid[$datum][1]; // Set datum Square of eccentricity |
$this->datum = $datum; // Save the datum |
} |
// |
// Set/Get X & Y pixel of the point (used if it is being drawn on an image) |
// |
function setXY($x, $y) |
{ |
$this->Xp = $x; $this->Yp = $y; |
} |
function Xp() { return $this->Xp; } |
function Yp() { return $this->Yp; } |
// |
// Set/Get/Output Longitude & Latitude of the point |
// |
function setLongLat($long, $lat) |
{ |
$this->long = $long; $this->lat = $lat; |
} |
function Lat() { return $this->lat; } |
function Long() { return $this->long; } |
function printLatLong() { printf("Latitude: %1.5f Longitude: %1.5f",$this->lat, $this->long); } |
// |
// Set/Get/Output Universal Transverse Mercator Coordinates |
// |
function setUTM($easting, $northing, $zone='') // Zone is optional |
{ |
$this->utmNorthing = $northing; |
$this->utmEasting = $easting; |
$this->utmZone = $zone; |
} |
function N() { return $this->utmNorthing; } |
function E() { return $this->utmEasting; } |
function Z() { return $this->utmZone; } |
function printUTM() { print( "Northing: ".(int)$this->utmNorthing.", Easting: ".(int)$this->utmEasting.", Zone: ".$this->utmZone); } |
// |
// Set/Get/Output Lambert Conic Conformal Coordinates |
// |
function setLambert($easting, $northing) |
{ |
$this->lccNorthing = $northing; |
$this->lccEasting = $easting; |
} |
function lccN() { return $this->lccNorthing; } |
function lccE() { return $this->lccEasting; } |
function printLambert() { print( "Northing: ".(int)$this->lccNorthing.", Easting: ".(int)$this->lccEasting); } |
|
//------------------------------------------------------------------------------ |
// |
// Convert Longitude/Latitude to UTM |
// |
// Equations from USGS Bulletin 1532 |
// East Longitudes are positive, West longitudes are negative. |
// North latitudes are positive, South latitudes are negative |
// Lat and Long are in decimal degrees |
// Written by Chuck Gantz- chuck dot gantz at globalstar dot com, converted to PHP by |
// Brenor Brophy, brenor dot brophy at gmail dot com |
// |
// UTM coordinates are useful when dealing with paper maps. Basically the |
// map will can cover a single UTM zone which is 6 degrees on longitude. |
// So you really don't care about an object crossing two zones. You just get a |
// second map of the other zone. However, if you happen to live in a place that |
// straddles two zones (For example the Santa Babara area in CA straddles zone 10 |
// and zone 11) Then it can become a real pain having to have two maps all the time. |
// So relatively small parts of the world (like say California) create their own |
// version of UTM coordinates that are adjusted to conver the whole area of interest |
// on a single map. These are called state grids. The projection system is the |
// usually same as UTM (i.e. Transverse Mercator), but the central meridian |
// aka Longitude of Origin is selected to suit the logitude of the area being |
// mapped (like being moved to the central meridian of the area) and the grid |
// may cover more than the 6 degrees of lingitude found on a UTM map. Areas |
// that are wide rather than long - think Montana as an example. May still |
// have to have a couple of maps to cover the whole state because TM projection |
// looses accuracy as you move further away from the Longitude of Origin, 15 degrees |
// is usually the limit. |
// |
// Now, in the case where we want to generate electronic maps that may be |
// placed pretty much anywhere on the globe we really don't to deal with the |
// issue of UTM zones in our coordinate system. We would really just like a |
// grid that is fully contigious over the area of the map we are drawing. Similiar |
// to the state grid, but local to the area we are interested in. I call this |
// Local Transverse Mercator and I have modified the function below to also |
// make this conversion. If you pass a Longitude value to the function as $LongOrigin |
// then that is the Longitude of Origin that will be used for the projection. |
// Easting coordinates will be returned (in meters) relative to that line of |
// longitude - So an Easting coordinate for a point located East of the longitude |
// of origin will be a positive value in meters, an Easting coordinate for a point |
// West of the longitude of Origin will have a negative value in meters. Northings |
// will always be returned in meters from the equator same as the UTM system. The |
// UTMZone value will be valid for Long/Lat given - thought it is not meaningful |
// in the context of Local TM. If a NULL value is passed for $LongOrigin |
// then the standard UTM coordinates are calculated. |
// |
function convertLLtoTM($LongOrigin = NULL) |
{ |
$k0 = 0.9996; |
$falseEasting = 0.0; |
|
//Make sure the longitude is between -180.00 .. 179.9 |
$LongTemp = ($this->long+180)-(integer)(($this->long+180)/360)*360-180; // -180.00 .. 179.9; |
$LatRad = deg2rad($this->lat); |
$LongRad = deg2rad($LongTemp); |
|
if (!$LongOrigin) |
{ // Do a standard UTM conversion - so findout what zone the point is in |
$ZoneNumber = (integer)(($LongTemp + 180)/6) + 1; |
// Special zone for South Norway |
if( $this->lat >= 56.0 && $this->lat < 64.0 && $LongTemp >= 3.0 && $LongTemp < 12.0 ) // Fixed 1.1 |
$ZoneNumber = 32; |
// Special zones for Svalbard |
if( $this->lat >= 72.0 && $this->lat < 84.0 ) |
{ |
if( $LongTemp >= 0.0 && $LongTemp < 9.0 ) $ZoneNumber = 31; |
else if( $LongTemp >= 9.0 && $LongTemp < 21.0 ) $ZoneNumber = 33; |
else if( $LongTemp >= 21.0 && $LongTemp < 33.0 ) $ZoneNumber = 35; |
else if( $LongTemp >= 33.0 && $LongTemp < 42.0 ) $ZoneNumber = 37; |
} |
$LongOrigin = ($ZoneNumber - 1)*6 - 180 + 3; //+3 puts origin in middle of zone |
//compute the UTM Zone from the latitude and longitude |
$this->utmZone = sprintf("%d%s", $ZoneNumber, $this->UTMLetterDesignator()); |
// We also need to set the false Easting value adjust the UTM easting coordinate |
$falseEasting = 500000.0; |
} |
$LongOriginRad = deg2rad($LongOrigin); |
|
$eccPrimeSquared = ($this->e2)/(1-$this->e2); |
|
$N = $this->a/sqrt(1-$this->e2*sin($LatRad)*sin($LatRad)); |
$T = tan($LatRad)*tan($LatRad); |
$C = $eccPrimeSquared*cos($LatRad)*cos($LatRad); |
$A = cos($LatRad)*($LongRad-$LongOriginRad); |
|
$M = $this->a*((1 - $this->e2/4 - 3*$this->e2*$this->e2/64 - 5*$this->e2*$this->e2*$this->e2/256)*$LatRad |
- (3*$this->e2/8 + 3*$this->e2*$this->e2/32 + 45*$this->e2*$this->e2*$this->e2/1024)*sin(2*$LatRad) |
+ (15*$this->e2*$this->e2/256 + 45*$this->e2*$this->e2*$this->e2/1024)*sin(4*$LatRad) |
- (35*$this->e2*$this->e2*$this->e2/3072)*sin(6*$LatRad)); |
|
$this->utmEasting = ($k0*$N*($A+(1-$T+$C)*$A*$A*$A/6 |
+ (5-18*$T+$T*$T+72*$C-58*$eccPrimeSquared)*$A*$A*$A*$A*$A/120) |
+ $falseEasting); |
|
$this->utmNorthing = ($k0*($M+$N*tan($LatRad)*($A*$A/2+(5-$T+9*$C+4*$C*$C)*$A*$A*$A*$A/24 |
+ (61-58*$T+$T*$T+600*$C-330*$eccPrimeSquared)*$A*$A*$A*$A*$A*$A/720))); |
if($this->lat < 0) |
$this->utmNorthing += 10000000.0; //10000000 meter offset for southern hemisphere |
} |
// |
// This routine determines the correct UTM letter designator for the given latitude |
// returns 'Z' if latitude is outside the UTM limits of 84N to 80S |
// Written by Chuck Gantz- chuck dot gantz at globalstar dot com, converted to PHP by |
// Brenor Brophy, brenor dot brophy at gmail dot com |
// |
function UTMLetterDesignator() |
{ |
if((84 >= $this->lat) && ($this->lat >= 72)) $LetterDesignator = 'X'; |
else if((72 > $this->lat) && ($this->lat >= 64)) $LetterDesignator = 'W'; |
else if((64 > $this->lat) && ($this->lat >= 56)) $LetterDesignator = 'V'; |
else if((56 > $this->lat) && ($this->lat >= 48)) $LetterDesignator = 'U'; |
else if((48 > $this->lat) && ($this->lat >= 40)) $LetterDesignator = 'T'; |
else if((40 > $this->lat) && ($this->lat >= 32)) $LetterDesignator = 'S'; |
else if((32 > $this->lat) && ($this->lat >= 24)) $LetterDesignator = 'R'; |
else if((24 > $this->lat) && ($this->lat >= 16)) $LetterDesignator = 'Q'; |
else if((16 > $this->lat) && ($this->lat >= 8)) $LetterDesignator = 'P'; |
else if(( 8 > $this->lat) && ($this->lat >= 0)) $LetterDesignator = 'N'; |
else if(( 0 > $this->lat) && ($this->lat >= -8)) $LetterDesignator = 'M'; |
else if((-8 > $this->lat) && ($this->lat >= -16)) $LetterDesignator = 'L'; |
else if((-16 > $this->lat) && ($this->lat >= -24)) $LetterDesignator = 'K'; |
else if((-24 > $this->lat) && ($this->lat >= -32)) $LetterDesignator = 'J'; |
else if((-32 > $this->lat) && ($this->lat >= -40)) $LetterDesignator = 'H'; |
else if((-40 > $this->lat) && ($this->lat >= -48)) $LetterDesignator = 'G'; |
else if((-48 > $this->lat) && ($this->lat >= -56)) $LetterDesignator = 'F'; |
else if((-56 > $this->lat) && ($this->lat >= -64)) $LetterDesignator = 'E'; |
else if((-64 > $this->lat) && ($this->lat >= -72)) $LetterDesignator = 'D'; |
else if((-72 > $this->lat) && ($this->lat >= -80)) $LetterDesignator = 'C'; |
else $LetterDesignator = 'Z'; //This is here as an error flag to show that the Latitude is outside the UTM limits |
|
return($LetterDesignator); |
} |
|
//------------------------------------------------------------------------------ |
// |
// Convert UTM to Longitude/Latitude |
// |
// Equations from USGS Bulletin 1532 |
// East Longitudes are positive, West longitudes are negative. |
// North latitudes are positive, South latitudes are negative |
// Lat and Long are in decimal degrees. |
// Written by Chuck Gantz- chuck dot gantz at globalstar dot com, converted to PHP by |
// Brenor Brophy, brenor dot brophy at gmail dot com |
// |
// If a value is passed for $LongOrigin then the function assumes that |
// a Local (to the Longitude of Origin passed in) Transverse Mercator |
// coordinates is to be converted - not a UTM coordinate. This is the |
// complementary function to the previous one. The function cannot |
// tell if a set of Northing/Easting coordinates are in the North |
// or South hemesphere - they just give distance from the equator not |
// direction - so only northern hemesphere lat/long coordinates are returned. |
// If you live south of the equator there is a note later in the code |
// explaining how to have it just return southern hemesphere lat/longs. |
// |
function convertTMtoLL($LongOrigin = NULL) |
{ |
$k0 = 0.9996; |
$e1 = (1-sqrt(1-$this->e2))/(1+sqrt(1-$this->e2)); |
$falseEasting = 0.0; |
$y = $this->utmNorthing; |
|
if (!$LongOrigin) |
{ // It is a UTM coordinate we want to convert |
sscanf($this->utmZone,"%d%s",$ZoneNumber,$ZoneLetter); |
if($ZoneLetter >= 'N') |
$NorthernHemisphere = 1;//point is in northern hemisphere |
else |
{ |
$NorthernHemisphere = 0;//point is in southern hemisphere |
$y -= 10000000.0;//remove 10,000,000 meter offset used for southern hemisphere |
} |
$LongOrigin = ($ZoneNumber - 1)*6 - 180 + 3; //+3 puts origin in middle of zone |
$falseEasting = 500000.0; |
} |
|
// $y -= 10000000.0; // Uncomment line to make LOCAL coordinates return southern hemesphere Lat/Long |
$x = $this->utmEasting - $falseEasting; //remove 500,000 meter offset for longitude |
|
$eccPrimeSquared = ($this->e2)/(1-$this->e2); |
|
$M = $y / $k0; |
$mu = $M/($this->a*(1-$this->e2/4-3*$this->e2*$this->e2/64-5*$this->e2*$this->e2*$this->e2/256)); |
|
$phi1Rad = $mu + (3*$e1/2-27*$e1*$e1*$e1/32)*sin(2*$mu) |
+ (21*$e1*$e1/16-55*$e1*$e1*$e1*$e1/32)*sin(4*$mu) |
+(151*$e1*$e1*$e1/96)*sin(6*$mu); |
$phi1 = rad2deg($phi1Rad); |
|
$N1 = $this->a/sqrt(1-$this->e2*sin($phi1Rad)*sin($phi1Rad)); |
$T1 = tan($phi1Rad)*tan($phi1Rad); |
$C1 = $eccPrimeSquared*cos($phi1Rad)*cos($phi1Rad); |
$R1 = $this->a*(1-$this->e2)/pow(1-$this->e2*sin($phi1Rad)*sin($phi1Rad), 1.5); |
$D = $x/($N1*$k0); |
|
$tlat = $phi1Rad - ($N1*tan($phi1Rad)/$R1)*($D*$D/2-(5+3*$T1+10*$C1-4*$C1*$C1-9*$eccPrimeSquared)*$D*$D*$D*$D/24 |
+(61+90*$T1+298*$C1+45*$T1*$T1-252*$eccPrimeSquared-3*$C1*$C1)*$D*$D*$D*$D*$D*$D/720); // fixed in 1.1 |
$this->lat = rad2deg($tlat); |
|
$tlong = ($D-(1+2*$T1+$C1)*$D*$D*$D/6+(5-2*$C1+28*$T1-3*$C1*$C1+8*$eccPrimeSquared+24*$T1*$T1) |
*$D*$D*$D*$D*$D/120)/cos($phi1Rad); |
$this->long = $LongOrigin + rad2deg($tlong); |
} |
|
//------------------------------------------------------------------------------ |
// Configure a Lambert Conic Conformal Projection |
// |
// falseEasting & falseNorthing are just an offset in meters added to the final |
// coordinate calculated. |
// |
// longOfOrigin & LatOfOrigin are the "center" latitiude and longitude of the |
// area being projected. All coordinates will be calculated in meters relative |
// to this point on the earth. |
// |
// firstStdParallel & secondStdParallel are the two lines of longitude (that |
// is they run east-west) that define where the "cone" intersects the earth. |
// Simply put they should bracket the area being projected. |
// |
// google is your friend to find out more |
// |
function configLambertProjection ($falseEasting, $falseNorthing, |
$longOfOrigin, $latOfOrigin, |
$firstStdParallel, $secondStdParallel) |
{ |
$this->falseEasting = $falseEasting; |
$this->falseNorthing = $falseNorthing; |
$this->longOfOrigin = $longOfOrigin; |
$this->latOfOrigin = $latOfOrigin; |
$this->firstStdParallel = $firstStdParallel; |
$this->secondStdParallel = $secondStdParallel; |
} |
|
//------------------------------------------------------------------------------ |
// |
// Convert Longitude/Latitude to Lambert Conic Easting/Northing |
// |
// This routine will convert a Latitude/Longitude coordinate to an Northing/ |
// Easting coordinate on a Lambert Conic Projection. The configLambertProjection() |
// function should have been called prior to this one to setup the specific |
// parameters for the projection. The Northing/Easting parameters calculated are |
// in meters (because the datum used is in meters) and are relative to the |
// falseNorthing/falseEasting coordinate. Which in turn is relative to the |
// Lat/Long of origin The formula were obtained from URL: |
// http://www.ihsenergy.com/epsg/guid7_2.html. |
// Code was written by Brenor Brophy, brenor dot brophy at gmail dot com |
// |
function convertLLtoLCC() |
{ |
$e = sqrt($this->e2); |
|
$phi = deg2rad($this->lat); // Latitude to convert |
$phi1 = deg2rad($this->firstStdParallel); // Latitude of 1st std parallel |
$phi2 = deg2rad($this->secondStdParallel); // Latitude of 2nd std parallel |
$lamda = deg2rad($this->long); // Lonitude to convert |
$phio = deg2rad($this->latOfOrigin); // Latitude of Origin |
$lamdao = deg2rad($this->longOfOrigin); // Longitude of Origin |
|
$m1 = cos($phi1) / sqrt(( 1 - $this->e2*sin($phi1)*sin($phi1))); |
$m2 = cos($phi2) / sqrt(( 1 - $this->e2*sin($phi2)*sin($phi2))); |
$t1 = tan((pi()/4)-($phi1/2)) / pow(( ( 1 - $e*sin($phi1) ) / ( 1 + $e*sin($phi1) )),$e/2); |
$t2 = tan((pi()/4)-($phi2/2)) / pow(( ( 1 - $e*sin($phi2) ) / ( 1 + $e*sin($phi2) )),$e/2); |
$to = tan((pi()/4)-($phio/2)) / pow(( ( 1 - $e*sin($phio) ) / ( 1 + $e*sin($phio) )),$e/2); |
$t = tan((pi()/4)-($phi /2)) / pow(( ( 1 - $e*sin($phi ) ) / ( 1 + $e*sin($phi ) )),$e/2); |
$n = (log($m1)-log($m2)) / (log($t1)-log($t2)); |
$F = $m1/($n*pow($t1,$n)); |
$rf = $this->a*$F*pow($to,$n); |
$r = $this->a*$F*pow($t,$n); |
$theta = $n*($lamda - $lamdao); |
|
$this->lccEasting = $this->falseEasting + $r*sin($theta); |
$this->lccNorthing = $this->falseNorthing + $rf - $r*cos($theta); |
} |
//------------------------------------------------------------------------------ |
// |
// Convert Easting/Northing on a Lambert Conic projection to Longitude/Latitude |
// |
// This routine will convert a Lambert Northing/Easting coordinate to an |
// Latitude/Longitude coordinate. The configLambertProjection() function should |
// have been called prior to this one to setup the specific parameters for the |
// projection. The Northing/Easting parameters are in meters (because the datum |
// used is in meters) and are relative to the falseNorthing/falseEasting |
// coordinate. Which in turn is relative to the Lat/Long of origin The formula |
// were obtained from URL http://www.ihsenergy.com/epsg/guid7_2.html. Code |
// was written by Brenor Brophy, brenor dot brophy at gmail dot com |
// |
function convertLCCtoLL() |
{ |
$e = sqrt($this->e2); |
|
$phi1 = deg2rad($this->firstStdParallel); // Latitude of 1st std parallel |
$phi2 = deg2rad($this->secondStdParallel); // Latitude of 2nd std parallel |
$phio = deg2rad($this->latOfOrigin); // Latitude of Origin |
$lamdao = deg2rad($this->longOfOrigin); // Longitude of Origin |
$E = $this->lccEasting; |
$N = $this->lccNorthing; |
$Ef = $this->falseEasting; |
$Nf = $this->falseNorthing; |
|
$m1 = cos($phi1) / sqrt(( 1 - $this->e2*sin($phi1)*sin($phi1))); |
$m2 = cos($phi2) / sqrt(( 1 - $this->e2*sin($phi2)*sin($phi2))); |
$t1 = tan((pi()/4)-($phi1/2)) / pow(( ( 1 - $e*sin($phi1) ) / ( 1 + $e*sin($phi1) )),$e/2); |
$t2 = tan((pi()/4)-($phi2/2)) / pow(( ( 1 - $e*sin($phi2) ) / ( 1 + $e*sin($phi2) )),$e/2); |
$to = tan((pi()/4)-($phio/2)) / pow(( ( 1 - $e*sin($phio) ) / ( 1 + $e*sin($phio) )),$e/2); |
$n = (log($m1)-log($m2)) / (log($t1)-log($t2)); |
$F = $m1/($n*pow($t1,$n)); |
$rf = $this->a*$F*pow($to,$n); |
$r_ = sqrt( pow(($E-$Ef),2) + pow(($rf-($N-$Nf)),2) ); |
$t_ = pow($r_/($this->a*$F),(1/$n)); |
$theta_ = atan(($E-$Ef)/($rf-($N-$Nf))); |
|
$lamda = $theta_/$n + $lamdao; |
$phi0 = (pi()/2) - 2*atan($t_); |
$phi1 = (pi()/2) - 2*atan($t_*pow(((1-$e*sin($phi0))/(1+$e*sin($phi0))),$e/2)); |
$phi2 = (pi()/2) - 2*atan($t_*pow(((1-$e*sin($phi1))/(1+$e*sin($phi1))),$e/2)); |
$phi = (pi()/2) - 2*atan($t_*pow(((1-$e*sin($phi2))/(1+$e*sin($phi2))),$e/2)); |
|
$this->lat = rad2deg($phi); |
$this->long = rad2deg($lamda); |
} |
|
//------------------------------------------------------------------------------ |
// This is a useful function that returns the Great Circle distance from the |
// gPoint to another Long/Lat coordinate |
// |
// Result is returned as meters |
// |
function distanceFrom($lon1, $lat1) |
{ |
$lon1 = deg2rad($lon1); $lat1 = deg2rad($lat1); // Added in 1.3 |
$lon2 = deg2rad($this->Long()); $lat2 = deg2rad($this->Lat()); |
|
$theta = $lon2 - $lon1; |
$dist = acos(sin($lat1) * sin($lat2) + cos($lat1) * cos($lat2) * cos($theta)); |
|
// Alternative formula supposed to be more accurate for short distances |
// $dist = 2*asin(sqrt( pow(sin(($lat1-$lat2)/2),2) + cos($lat1)*cos($lat2)*pow(sin(($lon1-$lon2)/2),2))); |
return ( $dist * 6366710 ); // from http://williams.best.vwh.net/avform.htm#GCF |
} |
|
//------------------------------------------------------------------------------ |
// This function also calculates the distance between two points. In this case |
// it just uses Pythagoras's theorm using TM coordinates. |
// |
function distanceFromTM(&$pt) |
{ |
$E1 = $pt->E(); $N1 = $pt->N(); |
$E2 = $this->E(); $N2 = $this->N(); |
|
$dist = sqrt(pow(($E1-$E2),2)+pow(($N1-$N2),2)); |
return $dist; |
} |
|
//------------------------------------------------------------------------------ |
// This function geo-references a geoPoint to a given map. This means that it |
// calculates the x,y pixel coordinate that coresponds to the Lat/Long value of |
// the geoPoint. The calculation is done using the Transverse Mercator(TM) |
// coordinates of the gPoint with respect to the TM coordinates of the center |
// point of the map. So this only makes sense if you are using Local TM |
// projection. |
// |
// $rX & $rY are the pixel coordinates that corespond to the Northing/Easting |
// ($rE/$rN) coordinate it is to this coordinate that the point will be |
// geo-referenced. The $LongOrigin is needed to make sure the Easting/Northing |
// coordinates of the point are correctly converted. |
// |
function gRef($rX, $rY, $rE, $rN, $Scale, $LongOrigin) |
{ |
$this->convertLLtoTM($LongOrigin); |
$x = (($this->E() - $rE) / $Scale) // The easting in meters times the scale to get pixels |
// is relative to the center of the image so adjust to |
+ ($rX); // the left coordinate. |
$y = $rY - // Adjust to bottom coordinate. |
(($rN - $this->N()) / $Scale); // The northing in meters |
// relative to the equator. Subtract center point northing |
// to get relative to image center and convert meters to pixels |
$this->setXY((int)$x,(int)$y); // Save the geo-referenced result. |
} |
} // end of class gPoint |
|
?> |