Google coordinates tot Lambert 72

Exec_Anon.cls

double lat = 50.3803887;
double lng =  4.9853501;

double LongRef = 0.076042943;
double bLamb = 6378388 * (1 - (1 / 297));
double aCarre = Math.pow(double.valueOf(6378388.0), double.valueOf(2.0));
double eCarre = (aCarre - Math.Pow(bLamb, double.valueOf(2.0))) / aCarre;
double KLamb = 11565915.812935;
double nLamb = 0.7716421928;

double eLamb = Math.Sqrt(eCarre);
double eSur2 = eLamb / 2;

lat = (Math.PI / 180) * lat;
lng = (Math.PI / 180) * lng;

double eSinLatitude = eLamb * Math.Sin(lat);
double TanZDemi = (Math.Tan((Math.PI / 4) - (lat / 2))) * (Math.Pow(((1 + (eSinLatitude)) / (1 - (eSinLatitude))), (eSur2)));

double RLamb = KLamb * (Math.Pow((TanZDemi), nLamb));

double Teta = nLamb * (lng - LongRef);

decimal x = 0;
decimal y = 0;

x = 150000 + 0.01256 + RLamb * Math.Sin(Teta - 0.000142043);
y = 5400000 + 88.4378 - RLamb * Math.Cos(Teta - 0.000142043);

System.debug(String.format('http://bdes.spw.wallonie.be/portal/#BBOX={0},{0},{1},{1}', new List<String>{String.valueOf(x), String.valueOf(y)}));