public double getEastIntensity( double dlat, double dlong, double year, double altitude )
    {
            calcGeoMag( dlat, dlong, year, altitude );
            return  bx;
    }
public double getEastIntensity ( double dlat , double dlong , double year , double altitude ) { calcGeoMag ( dlat , dlong , year , altitude ) ; return bx ; }
Returns the easterly magnetic field intensity from the
Department of Defense geomagnetic model and data
in nano Tesla.

@param	dlat	 	Latitude in decimal degrees.
@param 	dlong		Longitude in decimal degrees.
@param	year		Date of the calculation in decimal years.
@param	altitude	Altitude of the calculation in kilometers.

@return  The easterly component of the magnetic field strength in nano Tesla.