NETGeographicLib  1.51
Public Member Functions | Static Public Member Functions | List of all members
NETGeographicLib::MagneticModel Class Reference

.NET wrapper for GeographicLib::MagneticModel. More...

#include <NETGeographicLib/MagneticModel.h>

Public Member Functions

 ~MagneticModel ()
 
Setting up the magnetic model
 MagneticModel (System::String^ name, System::String^ path, Geocentric^ earth)
 
 MagneticModel (System::String^ name, System::String^ path)
 

Static Public Member Functions

static System::String ^ DefaultMagneticPath ()
 
static System::String ^ DefaultMagneticName ()
 

Properties

Inspector functions
System::String^ Description [get]
 
System::String^ DateTime [get]
 
System::String^ MagneticFile [get]
 
System::String^ MagneticModelName [get]
 
System::String^ MagneticModelDirectory [get]
 
double MinHeight [get]
 
double MaxHeight [get]
 
double MinTime [get]
 
double MaxTime [get]
 
double EquatorialRadius [get]
 
double Flattening [get]
 

Compute the magnetic field

void Field (double t, double lat, double lon, double h, [System::Runtime::InteropServices::Out] double% Bx, [System::Runtime::InteropServices::Out] double% By, [System::Runtime::InteropServices::Out] double% Bz)
 
void Field (double t, double lat, double lon, double h, [System::Runtime::InteropServices::Out] double% Bx, [System::Runtime::InteropServices::Out] double% By, [System::Runtime::InteropServices::Out] double% Bz, [System::Runtime::InteropServices::Out] double% Bxt, [System::Runtime::InteropServices::Out] double% Byt, [System::Runtime::InteropServices::Out] double% Bzt)
 
MagneticCircleCircle (double t, double lat, double h)
 
static void FieldComponents (double Bx, double By, double Bz, [System::Runtime::InteropServices::Out] double% H, [System::Runtime::InteropServices::Out] double% F, [System::Runtime::InteropServices::Out] double% D, [System::Runtime::InteropServices::Out] double% I)
 
static void FieldComponents (double Bx, double By, double Bz, double Bxt, double Byt, double Bzt, [System::Runtime::InteropServices::Out] double% H, [System::Runtime::InteropServices::Out] double% F, [System::Runtime::InteropServices::Out] double% D, [System::Runtime::InteropServices::Out] double% I, [System::Runtime::InteropServices::Out] double% Ht, [System::Runtime::InteropServices::Out] double% Ft, [System::Runtime::InteropServices::Out] double% Dt, [System::Runtime::InteropServices::Out] double% It)
 

Detailed Description

.NET wrapper for GeographicLib::MagneticModel.

This class allows .NET applications to access GeographicLib::MagneticModel.

Evaluate the earth's magnetic field according to a model. At present only internal magnetic fields are handled. These are due to the earth's code and crust; these vary slowly (over many years). Excluded are the effects of currents in the ionosphere and magnetosphere which have daily and annual variations.

See Magnetic models for details of how to install the magnetic model and the data format.

See

C# Example:

using System;
namespace example_MagneticModel
{
class Program
{
static void Main(string[] args)
{
try {
MagneticModel mag = new MagneticModel("wmm2010","");
double lat = 27.99, lon = 86.93, h = 8820, t = 2012; // Mt Everest
double Bx, By, Bz;
mag.Field(t, lat,lon, h, out Bx, out By, out Bz);
double H, F, D, I;
MagneticModel.FieldComponents(Bx, By, Bz, out H, out F, out D, out I);
Console.WriteLine(String.Format("{0} {1} {2} {3}", H, F, D, I));
}
catch (GeographicErr e) {
Console.WriteLine(String.Format("Caught exception: {0}", e.Message));
}
}
}
}

Managed C++ Example:

using namespace System;
using namespace NETGeographicLib;
int main(array<System::String ^> ^/*args*/)
{
try {
MagneticModel^ mag = gcnew MagneticModel("wmm2010","");
double lat = 27.99, lon = 86.93, h = 8820, t = 2012; // Mt Everest
double Bx, By, Bz;
mag->Field(t, lat,lon, h, Bx, By, Bz);
double H, F, D, I;
MagneticModel::FieldComponents(Bx, By, Bz, H, F, D, I);
Console::WriteLine(String::Format("{0} {1} {2} {3}", H, F, D, I));
}
catch (GeographicErr^ e) {
Console::WriteLine(String::Format("Caught exception: {0}", e->Message));
return -1;
}
return 0;
}

Visual Basic Example:

Imports NETGeographicLib
Module example_MagneticModel
Sub Main()
Try
Dim mag As MagneticModel = New MagneticModel("wmm2010", "")
Dim lat As Double = 27.99, lon = 86.93, h = 8820, t = 2012 ' Mt Everest
Dim Bx, By, Bz As Double
mag.Field(t, lat, lon, H, Bx, By, Bz)
Dim bigH, F, D, I As Double
MagneticModel.FieldComponents(Bx, By, Bz, bigH, F, D, I)
Console.WriteLine(String.Format("{0} {1} {2} {3}", bigH, F, D, I))
Catch ex As GeographicErr
Console.WriteLine(String.Format("Caught exception: {0}", ex.Message))
End Try
End Sub
End Module

INTERFACE DIFFERENCES:
The () operator has been replaced with Field.

The following functions are implemented as properties: Description, DateTime, MagneticFile, MagneticModelName, MagneticModelDirectory, MinHeight, MaxHeight, MinTime, MaxTime, EquatorialRadius, and Flattening.

Definition at line 69 of file MagneticModel.h.

Constructor & Destructor Documentation

◆ MagneticModel() [1/2]

NETGeographicLib::MagneticModel::MagneticModel ( System::String^  name,
System::String^  path,
Geocentric earth 
)

Construct a magnetic model.

Parameters
[in]namethe name of the model.
[in]path(optional) directory for data file.
[in]earth(optional) Geocentric object for converting coordinates.
Exceptions
GeographicErrif the data file cannot be found, is unreadable, or is corrupt.
std::bad_allocif the memory necessary for storing the model can't be allocated.

A filename is formed by appending ".wmm" (World Magnetic Model) to the name. If path is specified (and is non-empty), then the file is loaded from directory, path. Otherwise the path is given by the DefaultMagneticPath().

This file contains the metadata which specifies the properties of the model. The coefficients for the spherical harmonic sums are obtained from a file obtained by appending ".cof" to metadata file (so the filename ends in ".wwm.cof").

The model is not tied to a particular ellipsoidal model of the earth. The final earth argument to the constructor specifies an ellipsoid to allow geodetic coordinates to the transformed into the spherical coordinates used in the spherical harmonic sum.

Referenced by ~MagneticModel().

◆ MagneticModel() [2/2]

NETGeographicLib::MagneticModel::MagneticModel ( System::String^  name,
System::String^  path 
)

Construct a magnetic model that assumes the WGS84 ellipsoid.

Parameters
[in]namethe name of the model.
[in]path(optional) directory for data file.
Exceptions
GeographicErrif the data file cannot be found, is unreadable, or is corrupt.
GeographicErrif the memory necessary for storing the model can't be allocated.

A filename is formed by appending ".wmm" (World Magnetic Model) to the name. If path is specified (and is non-empty), then the file is loaded from directory, path. Otherwise the path is given by the DefaultMagneticPath().

This file contains the metadata which specifies the properties of the model. The coefficients for the spherical harmonic sums are obtained from a file obtained by appending ".cof" to metadata file (so the filename ends in ".wwm.cof").

The model is not tied to a particular ellipsoidal model of the earth. The final earth argument to the constructor specifies an ellipsoid to allow geodetic coordinates to the transformed into the spherical coordinates used in the spherical harmonic sum.

◆ ~MagneticModel()

NETGeographicLib::MagneticModel::~MagneticModel ( )
inline

The destructor calls the finalizer.

Definition at line 144 of file MagneticModel.h.

References MagneticModel().

Member Function Documentation

◆ Field() [1/2]

void NETGeographicLib::MagneticModel::Field ( double  t,
double  lat,
double  lon,
double  h,
[System::Runtime::InteropServices::Out] double%  Bx,
[System::Runtime::InteropServices::Out] double%  By,
[System::Runtime::InteropServices::Out] double%  Bz 
)

Evaluate the components of the geomagnetic field.

Parameters
[in]tthe time (years).
[in]latlatitude of the point (degrees).
[in]lonlongitude of the point (degrees).
[in]hthe height of the point above the ellipsoid (meters).
[out]Bxthe easterly component of the magnetic field (nanotesla).
[out]Bythe northerly component of the magnetic field (nanotesla).
[out]Bzthe vertical (up) component of the magnetic field (nanotesla).

◆ Field() [2/2]

void NETGeographicLib::MagneticModel::Field ( double  t,
double  lat,
double  lon,
double  h,
[System::Runtime::InteropServices::Out] double%  Bx,
[System::Runtime::InteropServices::Out] double%  By,
[System::Runtime::InteropServices::Out] double%  Bz,
[System::Runtime::InteropServices::Out] double%  Bxt,
[System::Runtime::InteropServices::Out] double%  Byt,
[System::Runtime::InteropServices::Out] double%  Bzt 
)

Evaluate the components of the geomagnetic field and their time derivatives

Parameters
[in]tthe time (years).
[in]latlatitude of the point (degrees).
[in]lonlongitude of the point (degrees).
[in]hthe height of the point above the ellipsoid (meters).
[out]Bxthe easterly component of the magnetic field (nanotesla).
[out]Bythe northerly component of the magnetic field (nanotesla).
[out]Bzthe vertical (up) component of the magnetic field (nanotesla).
[out]Bxtthe rate of change of Bx (nT/yr).
[out]Bytthe rate of change of By (nT/yr).
[out]Bztthe rate of change of Bz (nT/yr).

◆ Circle()

MagneticCircle ^ NETGeographicLib::MagneticModel::Circle ( double  t,
double  lat,
double  h 
)

Create a MagneticCircle object to allow the geomagnetic field at many points with constant lat, h, and t and varying lon to be computed efficiently.

Parameters
[in]tthe time (years).
[in]latlatitude of the point (degrees).
[in]hthe height of the point above the ellipsoid (meters).
Exceptions
std::bad_allocif the memory necessary for creating a MagneticCircle can't be allocated.
Returns
a MagneticCircle object whose MagneticCircle::Field(double lon) member function computes the field at particular values of lon.

If the field at several points on a circle of latitude need to be calculated then creating a MagneticCircle and using its member functions will be substantially faster, especially for high-degree models.

◆ FieldComponents() [1/2]

static void NETGeographicLib::MagneticModel::FieldComponents ( double  Bx,
double  By,
double  Bz,
[System::Runtime::InteropServices::Out] double%  H,
[System::Runtime::InteropServices::Out] double%  F,
[System::Runtime::InteropServices::Out] double%  D,
[System::Runtime::InteropServices::Out] double%  I 
)
static

Compute various quantities dependent on the magnetic field.

Parameters
[in]Bxthe x (easterly) component of the magnetic field (nT).
[in]Bythe y (northerly) component of the magnetic field (nT).
[in]Bzthe z (vertical, up positive) component of the magnetic field (nT).
[out]Hthe horizontal magnetic field (nT).
[out]Fthe total magnetic field (nT).
[out]Dthe declination of the field (degrees east of north).
[out]Ithe inclination of the field (degrees down from horizontal).

◆ FieldComponents() [2/2]

static void NETGeographicLib::MagneticModel::FieldComponents ( double  Bx,
double  By,
double  Bz,
double  Bxt,
double  Byt,
double  Bzt,
[System::Runtime::InteropServices::Out] double%  H,
[System::Runtime::InteropServices::Out] double%  F,
[System::Runtime::InteropServices::Out] double%  D,
[System::Runtime::InteropServices::Out] double%  I,
[System::Runtime::InteropServices::Out] double%  Ht,
[System::Runtime::InteropServices::Out] double%  Ft,
[System::Runtime::InteropServices::Out] double%  Dt,
[System::Runtime::InteropServices::Out] double%  It 
)
static

Compute various quantities dependent on the magnetic field and its rate of change.

Parameters
[in]Bxthe x (easterly) component of the magnetic field (nT).
[in]Bythe y (northerly) component of the magnetic field (nT).
[in]Bzthe z (vertical, up positive) component of the magnetic field (nT).
[in]Bxtthe rate of change of Bx (nT/yr).
[in]Bytthe rate of change of By (nT/yr).
[in]Bztthe rate of change of Bz (nT/yr).
[out]Hthe horizontal magnetic field (nT).
[out]Fthe total magnetic field (nT).
[out]Dthe declination of the field (degrees east of north).
[out]Ithe inclination of the field (degrees down from horizontal).
[out]Htthe rate of change of H (nT/yr).
[out]Ftthe rate of change of F (nT/yr).
[out]Dtthe rate of change of D (degrees/yr).
[out]Itthe rate of change of I (degrees/yr).

◆ DefaultMagneticPath()

static System::String ^ NETGeographicLib::MagneticModel::DefaultMagneticPath ( )
static
Returns
the default path for magnetic model data files.

This is the value of the environment variable GEOGRAPHICLIB_MAGNETIC_PATH, if set; otherwise, it is $GEOGRAPHICLIB_DATA/magnetic if the environment variable GEOGRAPHICLIB_DATA is set; otherwise, it is a compile-time default (/usr/local/share/GeographicLib/magnetic on non-Windows systems and C:/ProgramData/GeographicLib/magnetic on Windows systems).

◆ DefaultMagneticName()

static System::String ^ NETGeographicLib::MagneticModel::DefaultMagneticName ( )
static
Returns
the default name for the magnetic model.

This is the value of the environment variable GEOGRAPHICLIB_MAGNETIC_NAME, if set, otherwise, it is "wmm2020". The MagneticModel class does not use this function; it is just provided as a convenience for a calling program when constructing a MagneticModel object.

Property Documentation

◆ Description

System:: String^ NETGeographicLib::MagneticModel::Description
get
Returns
the description of the magnetic model, if available, from the Description file in the data file; if absent, return "NONE".

Definition at line 270 of file MagneticModel.h.

◆ DateTime

System:: String^ NETGeographicLib::MagneticModel::DateTime
get
Returns
date of the model, if available, from the ReleaseDate field in the data file; if absent, return "UNKNOWN".

Definition at line 276 of file MagneticModel.h.

◆ MagneticFile

System:: String^ NETGeographicLib::MagneticModel::MagneticFile
get
Returns
full file name used to load the magnetic model.

Definition at line 281 of file MagneticModel.h.

◆ MagneticModelName

System:: String^ NETGeographicLib::MagneticModel::MagneticModelName
get
Returns
"name" used to load the magnetic model (from the first argument of the constructor, but this may be overridden by the model file).

Definition at line 287 of file MagneticModel.h.

◆ MagneticModelDirectory

System:: String^ NETGeographicLib::MagneticModel::MagneticModelDirectory
get
Returns
directory used to load the magnetic model.

Definition at line 292 of file MagneticModel.h.

◆ MinHeight

double NETGeographicLib::MagneticModel::MinHeight
get
Returns
the minimum height above the ellipsoid (in meters) for which this MagneticModel should be used.

Because the model will typically provide useful results slightly outside the range of allowed heights, no check of t argument is made by MagneticModel::Field() or MagneticModel::Circle.

Definition at line 303 of file MagneticModel.h.

◆ MaxHeight

double NETGeographicLib::MagneticModel::MaxHeight
get
Returns
the maximum height above the ellipsoid (in meters) for which this MagneticModel should be used.

Because the model will typically provide useful results slightly outside the range of allowed heights, no check of t argument is made by MagneticModel::Field() or MagneticModel::Circle.

Definition at line 314 of file MagneticModel.h.

◆ MinTime

double NETGeographicLib::MagneticModel::MinTime
get
Returns
the minimum time (in years) for which this MagneticModel should be used.

Because the model will typically provide useful results slightly outside the range of allowed times, no check of t argument is made by MagneticModel::Field() or MagneticModel::Circle.

Definition at line 325 of file MagneticModel.h.

◆ MaxTime

double NETGeographicLib::MagneticModel::MaxTime
get
Returns
the maximum time (in years) for which this MagneticModel should be used.

Because the model will typically provide useful results slightly outside the range of allowed times, no check of t argument is made by MagneticModel::Field() or MagneticModel::Circle.

Definition at line 336 of file MagneticModel.h.

◆ EquatorialRadius

double NETGeographicLib::MagneticModel::EquatorialRadius
get
Returns
a the equatorial radius of the ellipsoid (meters). This is the value of a inherited from the Geocentric object used in the constructor.

Definition at line 343 of file MagneticModel.h.

◆ Flattening

double NETGeographicLib::MagneticModel::Flattening
get
Returns
f the flattening of the ellipsoid. This is the value inherited from the Geocentric object used in the constructor.

Definition at line 349 of file MagneticModel.h.


The documentation for this class was generated from the following file: