code: private void set3D(int row, int col, int N , Point3D_F64 location ) {
  		double _N = N;
  		double gridX = 2.0*(col/_N-0.5);
  		double gridY = 2.0*(0.5-row/_N);
  
  		location.set(gridX,gridY,0);
  	}
docs: Specifies 3D location of landmark in marker coordinate system
  @param row row in the QR code's grid coordinate system
  @param col column in the QR code's grid coordinate system
  @param N width of grid
  @param location (Output) location of feature in marker reference frame