earth_induction_model.cpp

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#include "earth_induction_model.h"
 
ROM induction_model_area_t earth_induction_model_t::induction_model_area[N_AREAS]=
    {
    { // DACH
        5.0, 17.0,  // left, right
        45.5, 54.5, // bottom, top
        { // declination
         6.484968023424757e-05,
         3.604728604727705e-04,
         -1.336631317399705e-02,
         4.889050343589380e-05,
         -2.518514818513759e-02,
         7.773881035432078e-01,
         3.234265734262655e-05,
         -5.884959737228114e-03,
         6.761925158171979e-01,
         -1.258303844027981e+01
        },
        { // inclination
        2.100890562426442e-04,
        1.581751581705888e-05,
        -4.628525320828570e-02,
        1.761874489119027e-05,
        -5.288711288658317e-03,
        3.919445685819016e+00,
        -2.156177156192702e-05,
        8.834347472689526e-05,
        2.775942807177114e-01,
        -4.126846312074665e+01
        },
    },
    { // europe
        -15.0, 30.0, // left, right
        25.0, 70,   // bottom, top
        { // declination
        5.121784702900829e-05,
        2.624098034879970e-04,
        -9.419552924210621e-03,
        5.343918890002500e-05,
        -1.631811030378127e-02,
        4.986530342769596e-01,
        1.713583700195904e-05,
        -5.343808350939929e-03,
        4.744005367709492e-01,
        -6.919556947352653e+00
        },
        { // inclination
         2.238116112917459e-04,
         2.208613842153091e-05,
         -4.838904340786659e-02,
         -2.229902111583445e-05,
         -4.774809334262235e-03,
         4.023802474337383e+00,
         -1.682245906466733e-05,
         2.375176076700740e-03,
         2.306371479408610e-01,
         -4.296960683967160e+01
        },
    },
    { // africa
        -20.0, 60.0, // left, right
        -35.0, 40,   // bottom, top
        { // declination
         1.120219493186473e-04,
         -1.225698952752873e-04,
         -7.129961078385496e-03,
         4.931655990117274e-05,
         1.665170371891766e-03,
         2.727567451221284e-01,
         2.910501686112947e-05,
         -7.035073356032582e-03,
         3.204208774791076e-01,
         -3.647158038091194e+00
        },
        { // inclination
        -5.433127444135837e-04,
        -1.137350438537858e-04,
        1.706516490386623e-02,
        -4.511218757889591e-05,
        2.879877325512916e-03,
        2.267568526704758e+00,
        -1.087813989819037e-04,
        8.725656228245442e-03,
        9.743230657776267e-02,
        -2.939792941166480e+01
        },
    },
    { // australia
        110.0, 155.0,   // left, right
        -40.0, -10.0,   // bottom, top
        { // declination
        5.546403635333835e-05,
        5.314915232219207e-04,
        -6.849943856443287e-02,
        2.958100087894962e-04,
        -6.622137658688818e-02,
        3.447689949284927e+00,
        -1.756972044942521e-05,
        1.504216579312397e-02,
        -2.809034281885659e+00,
        1.496901011293250e+02
        },
        { // inclination
        1.515805621426717e-04,
        -6.343899008870405e-05,
        3.528378997526102e-02,
        1.696309522522108e-05,
        -9.470688732882490e-03,
        3.205317922018218e+00,
        7.111255870608101e-05,
        -2.686844631767804e-02,
        3.351232420712531e+00,
        -1.530444949539504e+02
        },
    },
    { // usa
        -125.00, -70.0,   // left, right
        25.0, 70.0,   // bottom, top
        { // declination
        -2.224233201399186e-04,
        -2.670316634833714e-04,
        -3.074590220552326e-04,
        2.130731708230263e-05,
        1.579370819172795e-02,
        3.789060809334363e-01,
        3.173990524545548e-04,
        8.721041713129403e-02,
        7.211047791637301e+00,
        1.825984054809143e+02
        },
        { // inclination
        -3.849560141354113e-06,
        -2.177788276836292e-05,
        -7.379103859208931e-03,
        5.034913907563424e-05,
        1.093250782229599e-02,
        1.821453913909042e+00,
        -4.095350585248441e-05,
        -1.878072768345651e-02,
        -2.436546108993555e+00,
        -7.074741045769397e+01
        },
    },
    { // south america
        -80.0, -35.0,   // left, right
        -40.0, 0.0,   // bottom, top
        { // declination
        -8.916044734793926e-05,
        1.908992736525847e-04,
        1.652392774122049e-02,
        1.398940528909979e-04,
        3.388131087247316e-02,
        1.583093751030807e+00,
        1.856740161715831e-04,
        4.598409447651635e-02,
        3.046289860366367e+00,
        4.088154472938876e+01
        },
        { // inclination
        -1.286255971474346e-04,
        2.781668984274968e-04,
        2.629059668574044e-02,
        -1.218543392258984e-04,
        -1.875065502578563e-02,
        1.252153998646948e+00,
        3.690416840339815e-04,
        5.105259785530584e-02,
        1.123874609725794e+00,
        -2.658596083317213e+01
        },
    },
    { // new zealand
        165.0, 179.0,   // left, right
        -48.0, -34.0,   // bottom, top
        { // declination
        -4.681582034523041e-04,
        -1.557738480006262e-04,
        -1.268994777399856e-02,
        1.296230030474883e-04,
        -5.826325838030581e-02,
        4.597818314678237e+00,
        5.920060331854854e-05,
        -3.095091690537255e-02,
        5.258586646991417e+00,
        -2.986056257634996e+02
        },
        { // inclination
        -4.681582034523041e-04,
        -1.557738480006262e-04,
        -1.268994777399856e-02,
        1.296230030474883e-04,
        -5.826325838030581e-02,
        4.597818314678237e+00,
        5.920060331854854e-05,
        -3.095091690537255e-02,
        5.258586646991417e+00,
        -2.986056257634996e+02
        }
    },
    { // iceland
        -27.0, -10,   // left, right
        62.0, 67.0,   // bottom, top
        { // declination
         3.395061728377397e-04,
         2.189296771339499e-04,
         -6.009662636950348e-02,
         8.948842694970172e-05,
         -1.297184136811914e-02,
         3.430077823894929e+00,
         -4.013301226923895e-05,
         -7.373095729518413e-03,
         4.381600590526588e-01,
         -6.269987586975348e+01
        },
        { // inclination
         9.259259259281425e-05,
         7.371369600481330e-05,
         -2.444978868744518e-02,
         -5.757039657957875e-05,
         -1.281947515849284e-02,
         2.559575585207323e+00,
         -7.023277147074459e-06,
         4.725287483409718e-03,
         5.309824459025138e-01,
         -1.288763260689519e+01
        }
    }
    };
 
induction_values earth_induction_model_t::get_induction_data_at( double latitude, double longitude)
  {
    induction_values retv={ 0.0, 0.0, false};
 
    // try to find parameter set for given coordinates
    for( int parameter_set = 0; parameter_set < N_AREAS; ++parameter_set)
    {
    if( latitude < induction_model_area[parameter_set].latitude__limit_south)
      continue;
    if( latitude > induction_model_area[parameter_set].latitude__limit_north)
      continue;
    if( longitude < induction_model_area[parameter_set].longitude_limit_west)
      continue;
    if( longitude > induction_model_area[parameter_set].longitude_limit_east)
      continue;
 
    // valid parameter set found, now evaluate induction data
    retv.declination =
        induction_model_area[parameter_set].coefficients_declination[9] +
        induction_model_area[parameter_set].coefficients_declination[8] * longitude +
        induction_model_area[parameter_set].coefficients_declination[7] * longitude * longitude +
        induction_model_area[parameter_set].coefficients_declination[6] * longitude * longitude * longitude +
        induction_model_area[parameter_set].coefficients_declination[5] * latitude +
        induction_model_area[parameter_set].coefficients_declination[4] * latitude * longitude +
        induction_model_area[parameter_set].coefficients_declination[3] * latitude * longitude * longitude +
        induction_model_area[parameter_set].coefficients_declination[2] * latitude * latitude +
        induction_model_area[parameter_set].coefficients_declination[1] * latitude * latitude * longitude +
        induction_model_area[parameter_set].coefficients_declination[0] * latitude * latitude * latitude;
 
    retv.inclination =
        induction_model_area[parameter_set].coefficients_inclination[9] +
        induction_model_area[parameter_set].coefficients_inclination[8] * longitude +
        induction_model_area[parameter_set].coefficients_inclination[7] * longitude * longitude +
        induction_model_area[parameter_set].coefficients_inclination[6] * longitude * longitude * longitude +
        induction_model_area[parameter_set].coefficients_inclination[5] * latitude +
        induction_model_area[parameter_set].coefficients_inclination[4] * latitude * longitude +
        induction_model_area[parameter_set].coefficients_inclination[3] * latitude * longitude * longitude +
        induction_model_area[parameter_set].coefficients_inclination[2] * latitude * latitude +
        induction_model_area[parameter_set].coefficients_inclination[1] * latitude * latitude * longitude +
        induction_model_area[parameter_set].coefficients_inclination[0] * latitude * latitude * latitude;
 
     retv.valid = true;
     return retv;
    }
 
    // no area found
    retv.valid = false;
    return retv;
  }
 
earth_induction_model_t earth_induction_model;