ajaxcall.js

map.on('click', function(event){			
				
				var x1_wgs;
				var y1_wgs;
				
				async function ajax(x,y){
					const data = $.ajax({
						url:'/geocoding/egsa_2_wgs.php?x='+x+'&y='+y,	
						async:true,
						type:'GET',
						dataType: 'JSON',
						contentType: "application/json; charset=utf-8",				
						success: function (data) {	
							var x1_wgs = data['0'];
							var y1_wgs = data['1'];	
							
						}				 								
					});
					console.log(x1_wgs,y1_wgs);
							
				  }  
				
				if(startPoint.getGeometry() == null){
		
					startPoint.setGeometry(new ol.geom.Point(event.coordinate));			   
					var x = event.coordinate[0];
					var y = event.coordinate[1];
          	
          		 ajax(x,y);		
				
			 }

egsa_2_wgs.php

<?php 


class EGSA_2_WGS{


 public function egsa87xy_to_wgs84xy($x,$y,$z)
  {
   return(array ($x-199.723, $y+74.03, $z+246.018));
 }


 public function flh2xyz($ellipsoid,$phi,$lambda,$h)
//convert phi, lambda, h  to x,y,z - h height above ellipsoid surface
//EGSA87 and HTRS07 ellipsoids are the same and differ only by a fraction of a millimeter to WGS84 ellipsoid in small semi-axis
 {
   $phi=deg2rad($phi);
   $lambda=deg2rad($lambda);
   $a=6378137;  //equatorial radius
   if($ellipsoid=="WGS84") $f = 1/298.257223563;
   else if ($ellipsoid=="EGSA87" || $ellipsoid=="HTRS07") $f = 1/298.257222100882711243;
   $e2=2*$f-$f*$f;
   //$epsilon=$e2/(1-$e2);
   $greekni=$a/sqrt(1-$e2*sin($phi)*sin($phi));  //prime vertical radius of curvature at latitude φ
   $X=($greekni+$h)*cos($phi)*cos($lambda);
   $Y=($greekni+$h)*cos($phi)*sin($lambda);
   $Z=((1-$e2)*$greekni+$h)*sin($phi);
   //echo "\nIn function:".__FUNCTION__."\n";
   //print_r( get_defined_vars()); 
   return(array($X,$Y,$Z));
}


    public function to_fl_from_proj_xy($type, $east,$north)
//given x,y (east,north in greek UTM projection this function calulates the f,l on greek ellipsoid (GRS80) 
//the $type can be either EGSA87 or HTRS07 which differ only in the False Northing value
{
     $a=6378137;  //equatorial radius
     $f=1/298.257222100882711;
     //$a=6377563.396;			//airy
     //$f=1/299.32496;	//Airy
     $e=sqrt(2*$f-$f*$f);
     $l_orig=24*M_PI/180;				//Longitude of natural origin
     $f_orig=0*M_PI/180;				//Latitude of natural origin
     $k_orig=0.9996;			//Scale factor at natural origin
     $FE=500000;							//False easting
     if ($type=="EGSA87") $FN=0;			//False northing
     else if($type=="HTRS07") $FN=-2000000;     

     //$b=6356752.314140347;  //grs80: polar radius
     //$f=($a-$b)/$a;     

     $n=$f/(2-$f);
     $B=$a/(1+$n)*(1+$n*$n/4+$n*$n*$n*$n/64);     

     $h1=$n/2-2/3*$n*$n+5/16*$n*$n*$n+41/180*$n*$n*$n*$n;
     $h2=13/48*$n*$n-3/5*$n*$n*$n+557/1440*$n*$n*$n*$n;
     $h3=61/240*$n*$n*$n-103/140*$n*$n*$n*$n;
     $h4=49561/161280*$n*$n*$n*$n;     

     //meridional arc distance from equator to projection origin (Mo)
     $Qo=asinh(tan($f_orig))-$e*atanh($e * sin($f_orig));
     $bo=atan(sinh($Qo));
     $ksio0=asin(sin($bo));
     $ksio1=$h1*sin(2*$ksio0);
     $ksio2=$h2*sin(4*$ksio0);
     $ksio3=$h3*sin(6*$ksio0);
     $ksio4=$h4*sin(8*$ksio0);
     $ksio=$ksio0+$ksio1+$ksio2+$ksio3+$ksio4;
     $Mo=$B*$ksio;
     //up to here the same as toxy     

     $h1t=$n/2-2/3*$n*$n+37/96*$n*$n*$n-1/360*$n*$n*$n*$n;
     $h2t=1/48*$n*$n+1/15*$n*$n*$n-437/1440*$n*$n*$n*$n;
     $h3t=17/480*$n*$n*$n-37/840*$n*$n*$n*$n;
     $h4t=4397/161280*$n*$n*$n*$n;
     $itat=($east-$FE)/($B*$k_orig);
     $ksit=($north-$FN+$k_orig*$Mo)/($B*$k_orig);
     $ksi1t=$h1t*sin(2*$ksit)*cosh(2*$itat);
     $ita1t=$h1t*cos(2*$ksit)*sinh(2*$itat);
     $ksi2t=$h2t*sin(4*$ksit)*cosh(4*$itat);
     $ita2t=$h2t*cos(4*$ksit)*sinh(4*$itat);
     $ksi3t=$h3t*sin(6*$ksit)*cosh(6*$itat);
     $ita3t=$h3t*cos(6*$ksit)*sinh(6*$itat);
     $ksi4t=$h4t*sin(8*$ksit)*cosh(8*$itat);
     $ita4t=$h4t*cos(8*$ksit)*sinh(8*$itat);
     $ksi0t=$ksit-($ksi1t+$ksi2t+$ksi3t+$ksi4t);
     $ita0t=$itat-($ita1t+$ita2t+$ita3t+$ita4t);
     $vitat=asin(sin($ksi0t)/cosh($ita0t));
     $Qt=asinh(tan($vitat));
     $Qtt=$Qt+$e*atanh($e*tanh($Qt));
     do {
     	$Qtt_previous=$Qtt;
     	$Qtt=$Qt+$e*atanh($e*tanh($Qtt));
     } while(abs($Qtt-$Qtt_previous)>1e-12);
     $phi=atan(sinh($Qtt));
     $lambda=$l_orig+asin(tanh($ita0t)/cos($vitat));
     return(array(rad2deg($phi),rad2deg($lambda)));
   }



   public function xyz2flh($ellipsoid,$xo,$yo,$zo)
//convert x,y,z to phi, lambda, h 
//EGSA87 and HTRS07 ellipsoids are the same and differ only by a fraction of a millimeter to WGS84 ellipsoid in small semi-axis
   {
      $a=6378137;  //equatorial radius
      if($ellipsoid=="WGS84") $f = 1/298.257223563;
      else if ($ellipsoid=="EGSA87" || $ellipsoid=="HTRS07") $f = 1/298.257222100882711243;
      $e2=2*$f-$f*$f;
      $epsilon=$e2/(1-$e2);
      $bi=$a*(1-$f);
      $p=sqrt($xo*$xo+$yo*$yo);
      $q=atan($zo*$a/($p*$bi));
      $phi=atan(($zo+$epsilon*$bi*sin($q)*sin($q)*sin($q))/($p-$e2*$a*cos($q)*cos($q)*cos($q)));
      $greekni=$a/sqrt(1-$e2*sin($phi)*sin($phi));  //prime vertical radius of curvature at latitude φ
      $lambda=atan($yo/$xo);
      $h=$p/cos($phi)-$greekni;
      //echo "\nIn function:".__FUNCTION__."\n";
      //print_r( get_defined_vars()); 
      return(array(rad2deg($phi),rad2deg($lambda),$h));
    }




    public function EGSA87_to_WGS84($xi,$psi) {
//converts x,y (easting, northing) of  EGSA87 projection to φ,λ of WGS84
     $temparr=$this->to_fl_from_proj_xy("EGSA87", $xi,$psi);
     $temparr=$this->flh2xyz("EGSA87",$temparr[0],$temparr[1],0);
     $temparr=$this->egsa87xy_to_wgs84xy($temparr[0],$temparr[1],$temparr[2]);
     $temparr=$this->xyz2flh("WGS84",$temparr[0],$temparr[1],$temparr[2]);
    // print_r($temparr);
     return array($temparr[0],$temparr[1]);
     //return array($temparr[0]);     
   }


 }


 $x = $_GET['x'];

 $y = $_GET['y'];

 
 $trans = new EGSA_2_WGS();

 $returnValue1 = json_encode($trans->EGSA87_to_WGS84($x,$y));

header('Content-Type: application/json');

echo $returnValue1;



 

 ?>