GeomagnetismHeader.h

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#ifndef _POSIX_C_SOURCE
#define _POSIX_C_SOURCE
#endif
 
/*
 #ifndef EPOCHRANGE
 #define EPOCHRANGE (int)5
 #endif
*/
 
#ifndef GEOMAGHEADER_H
#define GEOMAGHEADER_H
 
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
 
#define READONLYMODE "r"
#define MAXLINELENGTH (1024)
#define NOOFPARAMS (15)
#define NOOFCOEFFICIENTS (7)
 
#define _DEGREE_NOT_FOUND (-2)
#define CALCULATE_NUMTERMS(N) (N * (N + 1) / 2 + N)
 
/*These error values come from the ISCWSA error model:
 *http://www.copsegrove.com/Pages/MWDGeomagneticModels.aspx
 */
#define INCL_ERROR_BASE (0.20)
#define DECL_ERROR_OFFSET_BASE (0.36)
#define F_ERROR_BASE (130)
#define DECL_ERROR_SLOPE_BASE (5000)
#define WMM_ERROR_MULTIPLIER 1.21
#define IGRF_ERROR_MULTIPLIER 1.21
 
/*These error values are the NCEI error model
 *
 */
#define WMMHR_UNCERTAINTY_F 134
#define WMMHR_UNCERTAINTY_H 130
#define WMMHR_UNCERTAINTY_X 135
#define WMMHR_UNCERTAINTY_Y 85
#define WMMHR_UNCERTAINTY_Z 134
#define WMMHR_UNCERTAINTY_I 0.19
#define WMMHR_UNCERTAINTY_D_OFFSET 0.25
#define WMMHR_UNCERTAINTY_D_COEF 5205
 
#define WMM_UNCERTAINTY_F 138
#define WMM_UNCERTAINTY_H 133
#define WMM_UNCERTAINTY_X 137
#define WMM_UNCERTAINTY_Y 89
#define WMM_UNCERTAINTY_Z 141
#define WMM_UNCERTAINTY_I 0.20
#define WMM_UNCERTAINTY_D_OFFSET 0.26
#define WMM_UNCERTAINTY_D_COEF 5417
 
#ifndef M_PI
#define M_PI ((2) * (acos(0.0)))
#endif
 
#define RAD2DEG(rad) ((rad) * (180.0L / M_PI))
#define DEG2RAD(deg) ((deg) * (M_PI / 180.0L))
#define ATanH(x) (0.5 * log((1 + x) / (1 - x)))
 
#ifndef TRUE
#define TRUE ((int)1)
#endif
#ifndef FALSE
#define FALSE ((int)0)
#endif
 
#define MAG_PS_MIN_LAT_DEGREE \
  -55 /* Minimum Latitude for  Polar Stereographic projection in degrees   */
#define MAG_PS_MAX_LAT_DEGREE \
  55 /* Maximum Latitude for Polar Stereographic projection in degrees     */
#define MAG_UTM_MIN_LAT_DEGREE \
  -80.5 /* Minimum Latitude for UTM projection in degrees   */
#define MAG_UTM_MAX_LAT_DEGREE \
  84.5 /* Maximum Latitude for UTM projection in degrees     */
 
#define MAG_GEO_POLE_TOLERANCE 1e-5
#define MAG_USE_GEOID \
  1 /* 1 Geoid - Ellipsoid difference should be corrected, 0 otherwise */
 
#define LAT_BOUND_MIN -90
#define LAT_BOUND_MAX 90
#define LON_BOUND_MIN -180
#define LON_BOUND_MAX 360
#define ALT_BOUND_MIN -10
#define NO_ALT_MAX -99999
#define USER_GAVE_UP -1
#define DEC_YEAR_BOUND_MIN 2024.866
#define DEC_YEAR_BOUND_MAX 2030
 
#define WGS84ON 1
#define MSLON 2
 
/*
Data types and prototype declaration for
World Magnetic Model (WMM) subroutines.
 
July 28, 2009
 
manoj.c.nair@noaa.gov*/
 
typedef struct {
  double EditionDate;
  double epoch; /*Base time of Geomagnetic model epoch (yrs)*/
  double min_year;
  char ModelName[32];
  double *Main_Field_Coeff_G;  /* C - Gauss coefficients of main geomagnetic
                                  model (nT) Index is (n * (n + 1) / 2 + m) */
  double *Main_Field_Coeff_H;  /* C - Gauss coefficients of main geomagnetic
                                  model (nT) */
  double *Secular_Var_Coeff_G; /* CD - Gauss coefficients of secular geomagnetic
                                  model (nT/yr) */
  double *Secular_Var_Coeff_H; /* CD - Gauss coefficients of secular geomagnetic
                                  model (nT/yr) */
  int nMax;                    /* Maximum degree of spherical harmonic model */
  int nMaxSecVar; /* Maximum degree of spherical harmonic secular model */
  int SecularVariationUsed; /* Whether or not the magnetic secular variation
                               vector will be needed by program*/
  double CoefficientFileEndDate;
 
} MAGtype_MagneticModel;
 
typedef struct {
  double a;     /*semi-major axis of the ellipsoid*/
  double b;     /*semi-minor axis of the ellipsoid*/
  double fla;   /* flattening */
  double epssq; /*first eccentricity squared */
  double eps;   /* first eccentricity */
  double re;    /* mean radius of  ellipsoid*/
} MAGtype_Ellipsoid;
 
typedef struct {
  double lambda;               /* longitude */
  double phi;                  /* geodetic latitude */
  double HeightAboveEllipsoid; /* height above the ellipsoid (HaE) */
  double HeightAboveGeoid;     /* (height above the EGM96 geoid model ) */
  int UseGeoid;
} MAGtype_CoordGeodetic;
 
typedef struct {
  double lambda; /* longitude*/
  double phig;   /* geocentric latitude*/
  double r;      /* distance from the center of the ellipsoid*/
} MAGtype_CoordSpherical;
 
typedef struct {
  int Year;
  int Month;
  int Day;
  double DecimalYear; /* decimal years */
} MAGtype_Date;
 
typedef struct {
  double *Pcup;  /* Legendre Function */
  double *dPcup; /* Derivative of Legendre fcn */
} MAGtype_LegendreFunction;
 
typedef struct {
  double Bx; /* North */
  double By; /* East */
  double Bz; /* Down */
} MAGtype_MagneticResults;
 
typedef struct {
  double
      *RelativeRadiusPower; /* [earth_reference_radius_km / sph. radius ]^n  */
  double *cos_mlambda; /*cp(m)  - cosine of (m*spherical coord. longitude)*/
  double *sin_mlambda; /* sp(m)  - sine of (m*spherical coord. longitude) */
} MAGtype_SphericalHarmonicVariables;
 
typedef struct {
  double Decl; /* 1. Angle between the magnetic field vector and true north,
                  positive east*/
  double Incl; /*2. Angle between the magnetic field vector and the horizontal
                  plane, positive down*/
  double F;    /*3. Magnetic Field Strength*/
  double H;    /*4. Horizontal Magnetic Field Strength*/
  double X;    /*5. Northern component of the magnetic field vector*/
  double Y;    /*6. Eastern component of the magnetic field vector*/
  double Z;    /*7. Downward component of the magnetic field vector*/
  double GV;   /*8. The Grid Variation*/
  double Decldot; /*9. Yearly Rate of change in declination*/
  double Incldot; /*10. Yearly Rate of change in inclination*/
  double Fdot;    /*11. Yearly rate of change in Magnetic field strength*/
  double Hdot;    /*12. Yearly rate of change in horizontal field strength*/
  double Xdot;    /*13. Yearly rate of change in the northern component*/
  double Ydot;    /*14. Yearly rate of change in the eastern component*/
  double Zdot;    /*15. Yearly rate of change in the downward component*/
  double GVdot;   /*16. Yearly rate of change in grid variation*/
} MAGtype_GeoMagneticElements;
 
typedef struct {
  int NumbGeoidCols;   /* 360 degrees of longitude at 15 minute spacing */
  int NumbGeoidRows;   /* 180 degrees of latitude  at 15 minute spacing */
  int NumbHeaderItems; /* min, max lat, min, max long, lat, long spacing*/
  int ScaleFactor;     /* 4 grid cells per degree at 15 minute spacing  */
  float *GeoidHeightBuffer;
  int NumbGeoidElevs;
  int Geoid_Initialized; /* indicates successful initialization */
  int UseGeoid;          /*Is the Geoid being used?*/
} MAGtype_Geoid;
 
typedef struct {
  int UseGradient;
  MAGtype_GeoMagneticElements GradPhi;    /* phi */
  MAGtype_GeoMagneticElements GradLambda; /* lambda */
  MAGtype_GeoMagneticElements GradZ;
} MAGtype_Gradient;
 
typedef struct {
  char Longitude[40];
  char Latitude[40];
} MAGtype_CoordGeodeticStr;
 
typedef struct {
  double Easting;  /* (X) in meters*/
  double Northing; /* (Y) in meters */
  int Zone;        /*UTM Zone*/
  char HemiSphere;
  double CentralMeridian;
  double ConvergenceOfMeridians;
  double PointScale;
} MAGtype_UTMParameters;
 
enum PARAMS {
  SHDF,
  MODELNAME,
  PUBLISHER,
  RELEASEDATE,
  DATACUTOFF,
  MODELSTARTYEAR,
  MODELENDYEAR,
  EPOCH,
  INTSTATICDEG,
  INTSECVARDEG,
  EXTSTATICDEG,
  EXTSECVARDEG,
  GEOMAGREFRAD,
  NORMALIZATION,
  SPATBASFUNC
};
 
enum COEFFICIENTS { IE, N, M, GNM, HNM, DGNM, DHNM };
 
enum YYYYMMDD { YEAR, MONTH, DAY };
 
/*Prototypes */
 
/*Functions that should be Magnetic Model member functions*/
 
/*Wrapper Functions*/
int MAG_Geomag(MAGtype_Ellipsoid Ellip, MAGtype_CoordSpherical CoordSpherical,
               MAGtype_CoordGeodetic CoordGeodetic,
               MAGtype_MagneticModel *TimedMagneticModel,
               MAGtype_GeoMagneticElements *GeoMagneticElements);
 
void MAG_Gradient(MAGtype_Ellipsoid Ellip, MAGtype_CoordGeodetic CoordGeodetic,
                  MAGtype_MagneticModel *TimedMagneticModel,
                  MAGtype_Gradient *Gradient);
 
int MAG_robustReadMagModels(char *filename,
                            MAGtype_MagneticModel *(*magneticmodels)[],
                            int array_size);
 
int MAG_SetDefaults(MAGtype_Ellipsoid *Ellip, MAGtype_Geoid *Geoid);
 
/*User Interface*/
 
void MAG_Error(int control);
 
void MAG_PrintGradient(MAGtype_Gradient Gradient);
 
void MAG_PrintUserData(MAGtype_GeoMagneticElements GeomagElements,
                       MAGtype_CoordGeodetic SpaceInput, MAGtype_Date TimeInput,
                       MAGtype_MagneticModel *MagneticModel,
                       MAGtype_Geoid *Geoid);
 
int MAG_Warnings(int control, double value,
                 MAGtype_MagneticModel *MagneticModel);
 
/*Memory and File Processing*/
 
MAGtype_LegendreFunction *MAG_AllocateLegendreFunctionMemory(int NumTerms);
 
MAGtype_MagneticModel *MAG_AllocateModelMemory(int NumTerms);
 
MAGtype_SphericalHarmonicVariables *MAG_AllocateSphVarMemory(int nMax);
 
void MAG_AssignHeaderValues(MAGtype_MagneticModel *model,
                            char values[][MAXLINELENGTH]);
 
void MAG_AssignMagneticModelCoeffs(MAGtype_MagneticModel *Assignee,
                                   MAGtype_MagneticModel *Source, int nMax,
                                   int nMaxSecVar);
 
int MAG_FreeMemory(MAGtype_MagneticModel *MagneticModel,
                   MAGtype_MagneticModel *TimedMagneticModel,
                   MAGtype_LegendreFunction *LegendreFunction);
 
int MAG_FreeLegendreMemory(MAGtype_LegendreFunction *LegendreFunction);
 
int MAG_FreeMagneticModelMemory(MAGtype_MagneticModel *MagneticModel);
 
int MAG_FreeSphVarMemory(MAGtype_SphericalHarmonicVariables *SphVar);
 
void MAG_PrintWMMFormat(char *filename, MAGtype_MagneticModel *MagneticModel);
 
void MAG_PrintEMMFormat(char *filename, char *filenameSV,
                        MAGtype_MagneticModel *MagneticModel);
 
void MAG_PrintSHDFFormat(char *filename,
                         MAGtype_MagneticModel *(*MagneticModel)[], int epochs);
 
int MAG_readMagneticModel(char *filename, MAGtype_MagneticModel *MagneticModel);
 
int MAG_readMagneticModel_SHDF(char *filename,
                               MAGtype_MagneticModel *(*magneticmodels)[],
                               int array_size);
 
char *MAG_Trim(char *str);
 
/*Conversions, Transformations, and other Calculations*/
void MAG_BaseErrors(double DeclCoef, double DeclBaseline, double InclOffset,
                    double FOffset, double Multiplier, double H,
                    double *DeclErr, double *InclErr, double *FErr);
 
int MAG_CalculateGeoMagneticElements(
    MAGtype_MagneticResults *MagneticResultsGeo,
    MAGtype_GeoMagneticElements *GeoMagneticElements);
 
void MAG_CalculateGradientElements(MAGtype_MagneticResults GradResults,
                                   MAGtype_GeoMagneticElements MagneticElements,
                                   MAGtype_GeoMagneticElements *GradElements);
 
int MAG_CalculateSecularVariationElements(
    MAGtype_MagneticResults MagneticVariation,
    MAGtype_GeoMagneticElements *MagneticElements);
 
int MAG_CalculateGridVariation(MAGtype_CoordGeodetic location,
                               MAGtype_GeoMagneticElements *elements);
 
void MAG_CartesianToGeodetic(MAGtype_Ellipsoid Ellip, double x, double y,
                             double z, MAGtype_CoordGeodetic *CoordGeodetic);
 
MAGtype_CoordGeodetic MAG_CoordGeodeticAssign(
    MAGtype_CoordGeodetic CoordGeodetic);
 
int MAG_DateToYear(MAGtype_Date *Calendar_Date, char *Error);
 
void MAG_DegreeToDMSstring(double DegreesOfArc, int UnitDepth, char *DMSstring);
 
void MAG_DMSstringToDegree(char *DMSstring, double *DegreesOfArc);
 
void MAG_ErrorCalc(MAGtype_GeoMagneticElements B,
                   MAGtype_GeoMagneticElements *Errors);
 
int MAG_GeodeticToSpherical(MAGtype_Ellipsoid Ellip,
                            MAGtype_CoordGeodetic CoordGeodetic,
                            MAGtype_CoordSpherical *CoordSpherical);
 
MAGtype_GeoMagneticElements MAG_GeoMagneticElementsAssign(
    MAGtype_GeoMagneticElements Elements);
 
MAGtype_GeoMagneticElements MAG_GeoMagneticElementsScale(
    MAGtype_GeoMagneticElements Elements, double factor);
 
MAGtype_GeoMagneticElements MAG_GeoMagneticElementsSubtract(
    MAGtype_GeoMagneticElements minuend,
    MAGtype_GeoMagneticElements subtrahend);
 
int MAG_GetTransverseMercator(MAGtype_CoordGeodetic CoordGeodetic,
                              MAGtype_UTMParameters *UTMParameters);
 
int MAG_GetUTMParameters(double Latitude, double Longitude, int *Zone,
                         char *Hemisphere, double *CentralMeridian);
 
int MAG_isNaN(double d);
 
int MAG_RotateMagneticVector(MAGtype_CoordSpherical,
                             MAGtype_CoordGeodetic CoordGeodetic,
                             MAGtype_MagneticResults MagneticResultsSph,
                             MAGtype_MagneticResults *MagneticResultsGeo);
 
void MAG_SphericalToCartesian(MAGtype_CoordSpherical CoordSpherical, double *x,
                              double *y, double *z);
 
void MAG_SphericalToGeodetic(MAGtype_Ellipsoid Ellip,
                             MAGtype_CoordSpherical CoordSpherical,
                             MAGtype_CoordGeodetic *CoordGeodetic);
 
void MAG_TMfwd4(double Eps, double Epssq, double K0R4, double K0R4oa,
                double Acoeff[], double Lam0, double K0, double falseE,
                double falseN, int XYonly, double Lambda, double Phi, double *X,
                double *Y, double *pscale, double *CoM);
 
int MAG_YearToDate(MAGtype_Date *Date);
 
/*Spherical Harmonics*/
 
int MAG_AssociatedLegendreFunction(MAGtype_CoordSpherical CoordSpherical,
                                   int nMax,
                                   MAGtype_LegendreFunction *LegendreFunction);
 
int MAG_CheckGeographicPole(MAGtype_CoordGeodetic *CoordGeodetic);
 
int MAG_ComputeSphericalHarmonicVariables(
    MAGtype_Ellipsoid Ellip, MAGtype_CoordSpherical CoordSpherical, int nMax,
    MAGtype_SphericalHarmonicVariables *SphVariables);
 
void MAG_GradY(MAGtype_Ellipsoid Ellip, MAGtype_CoordSpherical CoordSpherical,
               MAGtype_CoordGeodetic CoordGeodetic,
               MAGtype_MagneticModel *TimedMagneticModel,
               MAGtype_GeoMagneticElements GeoMagneticElements,
               MAGtype_GeoMagneticElements *GradYElements);
 
void MAG_GradYSummation(MAGtype_LegendreFunction *LegendreFunction,
                        MAGtype_MagneticModel *MagneticModel,
                        MAGtype_SphericalHarmonicVariables SphVariables,
                        MAGtype_CoordSpherical CoordSpherical,
                        MAGtype_MagneticResults *GradY);
 
int MAG_PcupHigh(double *Pcup, double *dPcup, double x, int nMax);
 
int MAG_PcupLow(double *Pcup, double *dPcup, double x, int nMax);
 
int MAG_SecVarSummation(MAGtype_LegendreFunction *LegendreFunction,
                        MAGtype_MagneticModel *MagneticModel,
                        MAGtype_SphericalHarmonicVariables SphVariables,
                        MAGtype_CoordSpherical CoordSpherical,
                        MAGtype_MagneticResults *MagneticResults);
 
int MAG_SecVarSummationSpecial(MAGtype_MagneticModel *MagneticModel,
                               MAGtype_SphericalHarmonicVariables SphVariables,
                               MAGtype_CoordSpherical CoordSpherical,
                               MAGtype_MagneticResults *MagneticResults);
 
int MAG_Summation(MAGtype_LegendreFunction *LegendreFunction,
                  MAGtype_MagneticModel *MagneticModel,
                  MAGtype_SphericalHarmonicVariables SphVariables,
                  MAGtype_CoordSpherical CoordSpherical,
                  MAGtype_MagneticResults *MagneticResults);
 
int MAG_SummationSpecial(MAGtype_MagneticModel *MagneticModel,
                         MAGtype_SphericalHarmonicVariables SphVariables,
                         MAGtype_CoordSpherical CoordSpherical,
                         MAGtype_MagneticResults *MagneticResults);
 
int MAG_TimelyModifyMagneticModel(MAGtype_Date UserDate,
                                  MAGtype_MagneticModel *MagneticModel,
                                  MAGtype_MagneticModel *TimedMagneticModel);
 
/*Geoid*/
 
int MAG_ConvertGeoidToEllipsoidHeight(MAGtype_CoordGeodetic *CoordGeodetic,
                                      MAGtype_Geoid *Geoid);
/*
 * The function Convert_Geoid_To_Ellipsoid_Height converts the specified WGS84
 * geoid height at the specified geodetic coordinates to the equivalent
 * ellipsoid height, using the EGM96 gravity model.
 *
 *    Latitude            : Geodetic latitude in radians           (input)
 *    Longitude           : Geodetic longitude in radians          (input)
 *    Geoid_Height        : Geoid height, in meters                (input)
 *    Ellipsoid_Height    : Ellipsoid height, in meters.           (output)
 *
 */
 
int MAG_GetGeoidHeight(double Latitude, double Longitude, double *DeltaHeight,
                       MAGtype_Geoid *Geoid);
/*
 * The private function Get_Geoid_Height returns the height of the
 * WGS84 geiod above or below the WGS84 ellipsoid,
 * at the specified geodetic coordinates,
 * using a grid of height adjustments from the EGM96 gravity model.
 *
 *    Latitude            : Geodetic latitude in radians           (input)
 *    Longitude           : Geodetic longitude in radians          (input)
 *    DeltaHeight         : Height Adjustment, in meters.          (output)
 *
 */
 
void MAG_EquivalentLatLon(double lat, double lon, double *repairedLat,
                          double *repairedLon);
 
void MAG_WMMErrorCalc(double H, MAGtype_GeoMagneticElements *Uncertainty);
void MAG_WMMHRErrorCalc(double H, MAGtype_GeoMagneticElements *Uncertainty);
void MAG_PrintUserDataWithUncertainty(
    MAGtype_GeoMagneticElements GeomagElements,
    MAGtype_GeoMagneticElements Errors, MAGtype_CoordGeodetic SpaceInput,
    MAGtype_Date TimeInput, MAGtype_MagneticModel *MagneticModel,
    MAGtype_Geoid *Geoid);
double MAG_dtstr_to_dyear(char *edit_date);
size_t MAG_strlcpy_equivalent(char *dst, char *src, size_t dstlen);
 
#ifdef __cplusplus
}
#endif
 
#endif /*GEOMAGHEADER_H*/