NETGeographicLib  1.50.1
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NETGeographicLib::GravityCircle Class Reference

.NET wrapper for GeographicLib::GravityCircle. More...

#include <NETGeographicLib/GravityCircle.h>

Public Member Functions

 GravityCircle (const GeographicLib::GravityCircle &gc)
 
 ~GravityCircle ()
 
Compute the gravitational field
double Gravity (double lon, [System::Runtime::InteropServices::Out] double% gx, [System::Runtime::InteropServices::Out] double% gy, [System::Runtime::InteropServices::Out] double% gz)
 
double Disturbance (double lon, [System::Runtime::InteropServices::Out] double% deltax, [System::Runtime::InteropServices::Out] double% deltay, [System::Runtime::InteropServices::Out] double% deltaz)
 
double GeoidHeight (double lon)
 
void SphericalAnomaly (double lon, [System::Runtime::InteropServices::Out] double% Dg01, [System::Runtime::InteropServices::Out] double% xi, [System::Runtime::InteropServices::Out] double% eta)
 
double W (double lon, [System::Runtime::InteropServices::Out] double% gX, [System::Runtime::InteropServices::Out] double% gY, [System::Runtime::InteropServices::Out] double% gZ)
 
double V (double lon, [System::Runtime::InteropServices::Out] double% GX, [System::Runtime::InteropServices::Out] double% GY, [System::Runtime::InteropServices::Out] double% GZ)
 
double T (double lon, [System::Runtime::InteropServices::Out] double% deltaX, [System::Runtime::InteropServices::Out] double% deltaY, [System::Runtime::InteropServices::Out] double% deltaZ)
 
double T (double lon)
 

Inspector functions

bool Init [get]
 
double EquatorialRadius [get]
 
double Flattening [get]
 
double Latitude [get]
 
double Height [get]
 
GravityModel::Mask Capabilities ()
 
bool Capabilities (GravityModel::Mask testcaps)
 

Detailed Description

.NET wrapper for GeographicLib::GravityCircle.

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

Evaluate the earth's gravity field on a circle of constant height and latitude. This uses a CircularEngine to pre-evaluate the inner sum of the spherical harmonic sum, allowing the values of the field at several different longitudes to be evaluated rapidly.

Use GravityModel::Circle to create a GravityCircle object. (The constructor for this class is private.)

See Geoid heights on a multi-processor system for an example of using GravityCircle (together with OpenMP) to speed up the computation of geoid heights.

C# Example:

using System;
namespace example_GravityCircle
{
class Program
{
static void Main(string[] args)
{
try {
GravityModel grav = new GravityModel("egm96", "");
double lat = 27.99, lon0 = 86.93, h = 8820; // Mt Everest
{
// Slow method of evaluating the values at several points on a circle of
// latitude.
for (int i = -5; i <= 5; ++i) {
double lon = lon0 + i * 0.2;
double gx, gy, gz;
grav.Gravity(lat, lon, h, out gx, out gy, out gz);
Console.WriteLine(String.Format("{0} {1} {2} {3}", lon, gx, gy, gz));
}
}
{
// Fast method of evaluating the values at several points on a circle of
// latitude using GravityCircle.
GravityCircle circ = grav.Circle(lat, h, GravityModel.Mask.ALL);
for (int i = -5; i <= 5; ++i) {
double lon = lon0 + i * 0.2;
double gx, gy, gz;
circ.Gravity(lon, out gx, out gy, out gz);
Console.WriteLine(String.Format("{0} {1} {2} {3}", lon, gx, gy, gz));
}
}
}
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 {
GravityModel^ grav = gcnew GravityModel("egm96", "");
double lat = 27.99, lon0 = 86.93, h = 8820; // Mt Everest
{
// Slow method of evaluating the values at several points on a circle of
// latitude.
for (int i = -5; i <= 5; ++i) {
double lon = lon0 + i * 0.2;
double gx, gy, gz;
grav->Gravity(lat, lon, h, gx, gy, gz);
Console::WriteLine(String::Format("{0} {1} {2} {3}", lon, gx, gy, gz));
}
}
{
// Fast method of evaluating the values at several points on a circle of
// latitude using GravityCircle.
for (int i = -5; i <= 5; ++i) {
double lon = lon0 + i * 0.2;
double gx, gy, gz;
circ->Gravity(lon, gx, gy, gz);
Console::WriteLine(String::Format("{0} {1} {2} {3}", lon, gx, gy, gz));
}
}
}
catch (GeographicErr^ e) {
Console::WriteLine(String::Format("Caught exception: {0}", e->Message));
return -1;
}
return 0;
}

Visual Basic Example:

Imports NETGeographicLib
Module example_GravityCircle
Sub Main()
Try
Dim grav As GravityModel = New GravityModel("egm96", "")
Dim lat As Double = 27.99, lon0 = 86.93, h = 8820 ' Mt Everest
' Slow method of evaluating the values at several points on a circle of
' latitude.
For i As Integer = -5 To 5
Dim lon As Double = lon0 + i * 0.2
Dim gx, gy, gz As Double
grav.Gravity(lat, lon, h, gx, gy, gz)
Console.WriteLine(String.Format("{0} {1} {2} {3}", lon, gx, gy, gz))
Next
' Fast method of evaluating the values at several points on a circle of
' latitude using GravityCircle.
Dim circ As GravityCircle = grav.Circle(lat, h, GravityModel.Mask.ALL)
For i As Integer = -5 To 5
Dim lon As Double = lon0 + i * 0.2
Dim gx, gy, gz As Double
circ.Gravity(lon, gx, gy, gz)
Console.WriteLine(String.Format("{0} {1} {2} {3}", lon, gx, gy, gz))
Next
Catch ex As GeographicErr
Console.WriteLine(String.Format("Caught exception: {0}", ex.Message))
End Try
End Sub
End Module

INTERFACE DIFFERENCES:
The following functions are implemented as properties: Init, EquatorialRadius, Flattening, Latitude, and Height.

The Capabilities functions accept and return the "capabilities mask" as a NETGeographicLib::GravityModel::Mask rather than an unsigned.

Definition at line 45 of file GravityCircle.h.

Constructor & Destructor Documentation

◆ GravityCircle()

NETGeographicLib::GravityCircle::GravityCircle ( const GeographicLib::GravityCircle gc)

A constructor that is initialized from an unmanaged GeographicLib::GravityCircle. For internal use only. Developers should use GravityModel::Circle to create a GavityCircle object.

Referenced by ~GravityCircle().

◆ ~GravityCircle()

NETGeographicLib::GravityCircle::~GravityCircle ( )
inline

The destructor calls the finalizer.

Definition at line 64 of file GravityCircle.h.

References GravityCircle().

Member Function Documentation

◆ Gravity()

double NETGeographicLib::GravityCircle::Gravity ( double  lon,
[System::Runtime::InteropServices::Out] double%  gx,
[System::Runtime::InteropServices::Out] double%  gy,
[System::Runtime::InteropServices::Out] double%  gz 
)

Evaluate the gravity.

Parameters
[in]lonthe geographic longitude (degrees).
[out]gxthe easterly component of the acceleration (m s−2).
[out]gythe northerly component of the acceleration (m s−2).
[out]gzthe upward component of the acceleration (m s−2); this is usually negative.
Returns
W the sum of the gravitational and centrifugal potentials.

The function includes the effects of the earth's rotation.

◆ Disturbance()

double NETGeographicLib::GravityCircle::Disturbance ( double  lon,
[System::Runtime::InteropServices::Out] double%  deltax,
[System::Runtime::InteropServices::Out] double%  deltay,
[System::Runtime::InteropServices::Out] double%  deltaz 
)

Evaluate the gravity disturbance vector.

Parameters
[in]lonthe geographic longitude (degrees).
[out]deltaxthe easterly component of the disturbance vector (m s−2).
[out]deltaythe northerly component of the disturbance vector (m s−2).
[out]deltazthe upward component of the disturbance vector (m s−2).
Returns
T the corresponding disturbing potential.

◆ GeoidHeight()

double NETGeographicLib::GravityCircle::GeoidHeight ( double  lon)

Evaluate the geoid height.

Parameters
[in]lonthe geographic longitude (degrees).
Returns
N the height of the geoid above the reference ellipsoid (meters).

Some approximations are made in computing the geoid height so that the results of the NGA codes are reproduced accurately. Details are given in Details of the geoid height and anomaly calculations.

◆ SphericalAnomaly()

void NETGeographicLib::GravityCircle::SphericalAnomaly ( double  lon,
[System::Runtime::InteropServices::Out] double%  Dg01,
[System::Runtime::InteropServices::Out] double%  xi,
[System::Runtime::InteropServices::Out] double%  eta 
)

Evaluate the components of the gravity anomaly vector using the spherical approximation.

Parameters
[in]lonthe geographic longitude (degrees).
[out]Dg01the gravity anomaly (m s−2).
[out]xithe northerly component of the deflection of the vertical (degrees).
[out]etathe easterly component of the deflection of the vertical (degrees).

The spherical approximation (see Heiskanen and Moritz, Sec 2-14) is used so that the results of the NGA codes are reproduced accurately. approximations used here. Details are given in Details of the geoid height and anomaly calculations.

◆ W()

double NETGeographicLib::GravityCircle::W ( double  lon,
[System::Runtime::InteropServices::Out] double%  gX,
[System::Runtime::InteropServices::Out] double%  gY,
[System::Runtime::InteropServices::Out] double%  gZ 
)

Evaluate the components of the acceleration due to gravity and the centrifugal acceleration in geocentric coordinates.

Parameters
[in]lonthe geographic longitude (degrees).
[out]gXthe X component of the acceleration (m s−2).
[out]gYthe Y component of the acceleration (m s−2).
[out]gZthe Z component of the acceleration (m s−2).
Returns
W = V + Φ the sum of the gravitational and centrifugal potentials (m2 s−2).

◆ V()

double NETGeographicLib::GravityCircle::V ( double  lon,
[System::Runtime::InteropServices::Out] double%  GX,
[System::Runtime::InteropServices::Out] double%  GY,
[System::Runtime::InteropServices::Out] double%  GZ 
)

Evaluate the components of the acceleration due to gravity in geocentric coordinates.

Parameters
[in]lonthe geographic longitude (degrees).
[out]GXthe X component of the acceleration (m s−2).
[out]GYthe Y component of the acceleration (m s−2).
[out]GZthe Z component of the acceleration (m s−2).
Returns
V = W - Φ the gravitational potential (m2 s−2).

◆ T() [1/2]

double NETGeographicLib::GravityCircle::T ( double  lon,
[System::Runtime::InteropServices::Out] double%  deltaX,
[System::Runtime::InteropServices::Out] double%  deltaY,
[System::Runtime::InteropServices::Out] double%  deltaZ 
)

Evaluate the components of the gravity disturbance in geocentric coordinates.

Parameters
[in]lonthe geographic longitude (degrees).
[out]deltaXthe X component of the gravity disturbance (m s−2).
[out]deltaYthe Y component of the gravity disturbance (m s−2).
[out]deltaZthe Z component of the gravity disturbance (m s−2).
Returns
T = W - U the disturbing potential (also called the anomalous potential) (m2 s−2).

◆ T() [2/2]

double NETGeographicLib::GravityCircle::T ( double  lon)

Evaluate disturbing potential in geocentric coordinates.

Parameters
[in]lonthe geographic longitude (degrees).
Returns
T = W - U the disturbing potential (also called the anomalous potential) (m2 s−2).

◆ Capabilities() [1/2]

GravityModel::Mask NETGeographicLib::GravityCircle::Capabilities ( )
Returns
caps the computational capabilities that this object was constructed with.

◆ Capabilities() [2/2]

bool NETGeographicLib::GravityCircle::Capabilities ( GravityModel::Mask  testcaps)
Parameters
[in]testcapsa set of bitor'ed GeodesicLine::mask values.
Returns
true if the GeodesicLine object has all these capabilities.

Property Documentation

◆ Init

bool NETGeographicLib::GravityCircle::Init
get
Returns
true if the object has been initialized.

Definition at line 203 of file GravityCircle.h.

◆ EquatorialRadius

double NETGeographicLib::GravityCircle::EquatorialRadius
get
Returns
a the equatorial radius of the ellipsoid (meters). This is the value inherited from the GravityModel object used in the constructor. This property throws an exception if the GravityCircles has not been initialized.

Definition at line 203 of file GravityCircle.h.

◆ Flattening

double NETGeographicLib::GravityCircle::Flattening
get
Returns
f the flattening of the ellipsoid. This is the value inherited from the GravityModel object used in the constructor. This property throws an exception if the GravityCircles has not been initialized.

Definition at line 203 of file GravityCircle.h.

◆ Latitude

double NETGeographicLib::GravityCircle::Latitude
get
Returns
the latitude of the circle (degrees). This property throws an exception if the GravityCircles has not been initialized.

Definition at line 203 of file GravityCircle.h.

◆ Height

double NETGeographicLib::GravityCircle::Height
get
Returns
the height of the circle (meters). This property throws an exception if the GravityCircles has not been initialized.

Definition at line 203 of file GravityCircle.h.


The documentation for this class was generated from the following file:
NETGeographicLib::GravityCircle
.NET wrapper for GeographicLib::GravityCircle.
Definition: GravityCircle.h:46
NETGeographicLib::GravityModel
.NET wrapper for GeographicLib::GravityModel.
Definition: GravityModel.h:84
NETGeographicLib::GeographicErr
Exception class for NETGeographicLib.
Definition: NETGeographicLib.h:133
main
int main(int argc, const char *const argv[])
NETGeographicLib::GravityModel::Gravity
double Gravity(double lat, double lon, double h, [System::Runtime::InteropServices::Out] double% gx, [System::Runtime::InteropServices::Out] double% gy, [System::Runtime::InteropServices::Out] double% gz)
NETGeographicLib::GravityModel::Circle
GravityCircle ^ Circle(double lat, double h, Mask caps)
NETGeographicLib::GravityCircle::GravityCircle
GravityCircle(const GeographicLib::GravityCircle &gc)
NETGeographicLib::GravityCircle::Gravity
double Gravity(double lon, [System::Runtime::InteropServices::Out] double% gx, [System::Runtime::InteropServices::Out] double% gy, [System::Runtime::InteropServices::Out] double% gz)
NETGeographicLib
Definition: Accumulator.h:14
NETGeographicLib::GravityModel::Mask::ALL
@ ALL