ossimEllipsoid Class Reference

#include <ossimEllipsoid.h>

Public Member Functions
	ossimEllipsoid (const ossimEllipsoid &ellipsoid)
	ossimEllipsoid (const ossimString &name, const ossimString &code, const double &major_axis, const double &minor_axis, ossim_uint32 epsg_code=0)
	ossimEllipsoid (const double &major_axis, const double &minor_axis)
	ossimEllipsoid ()
virtual	~ossimEllipsoid ()
const ossimString &	name () const
const ossimString &	code () const
const double &	a () const
const double &	b () const
const double &	getA () const
const double &	getB () const
const double &	getFlattening () const
void	setA (double a)
void	setB (double b)
void	setAB (double a, double b)
void	setEpsgCode (ossim_uint32 code)
double	eccentricitySquared () const
double	flattening () const
double	eccentricity () const
ossim_uint32	getEpsgCode () const
bool	nearestIntersection (const ossimEcefRay &ray, ossimEcefPoint &rtnPt) const
bool	nearestIntersection (const ossimEcefRay &ray, const double &offset, ossimEcefPoint &rtnPt) const
double	evaluate (const ossimEcefPoint &) const
void	gradient (const ossimEcefPoint &location, ossimEcefVector &result) const
ossimEcefVector	gradient (const ossimEcefPoint &loc) const
void	prinRadiiOfCurv (const ossimEcefPoint &location, double &merRadius, double &primeVert) const
void	jacobianWrtEcef (const ossimEcefPoint &location, NEWMAT::Matrix &jMat) const
void	jacobianWrtGeo (const ossimEcefPoint &location, NEWMAT::Matrix &jMat) const
double	geodeticRadius (const double &latitude) const
void	geodeticRadii (const double &latitude, ossimDpt &radii) const
void	latLonHeightToXYZ (double lat, double lon, double height, double &x, double &y, double &z) const
void	XYZToLatLonHeight (double x, double y, double z, double &lat, double &lon, double &height) const
void	computeLocalToWorldTransformFromXYZ (double x, double y, double z, ossimMatrix4x4 &localToWorld) const
bool	operator== (const ossimEllipsoid &rhs) const
bool	operator!= (const ossimEllipsoid &rhs) const
bool	loadState (const ossimKeywordlist &kwl, const char *prefix=0)
bool	saveState (ossimKeywordlist &kwl, const char *prefix=0) const
const ossimEllipsoid &	operator= (const ossimEllipsoid &copy_me)
virtual bool	isEqualTo (const ossimEllipsoid &rhs, ossimCompareType compareType=OSSIM_COMPARE_FULL) const

Protected Member Functions
void	computeFlattening ()

Protected Attributes
ossimString	theName
ossimString	theCode
ossim_uint32	theEpsgCode
double	theA
double	theB
double	theFlattening
double	theA_squared
double	theB_squared
double	theEccentricitySquared

Detailed Description

---

CLASS: ossimEllipsoid

Definition at line 38 of file ossimEllipsoid.h.

Constructor & Destructor Documentation

ossimEllipsoid() [1/4]

ossimEllipsoid::ossimEllipsoid

(

const ossimEllipsoid &

ellipsoid

)

CONSTRUCTORS...

Definition at line 42 of file ossimEllipsoid.cpp.

References ossimEllipsoidFactory::findEpsgCode(), ossimEllipsoidFactory::instance(), theCode, and theEpsgCode.

   :
      theName(ellipsoid.theName),
      theCode(ellipsoid.theCode),
      theEpsgCode(ellipsoid.theEpsgCode),
      theA(ellipsoid.theA),
      theB(ellipsoid.theB),
      theFlattening(ellipsoid.theFlattening),
      theA_squared(ellipsoid.theA_squared),
      theB_squared(ellipsoid.theB_squared),
      theEccentricitySquared(ellipsoid.theEccentricitySquared)
{
   if ( theEpsgCode == 0 )
   {
      theEpsgCode = ossimEllipsoidFactory::instance()->findEpsgCode(theCode);
   }
}

ossimEllipsoid() [2/4]

ossimEllipsoid::ossimEllipsoid	(	const ossimString &	name,
		const ossimString &	code,
		const double &	major_axis,
		const double &	minor_axis,
		ossim_uint32	epsg_code = 0
	)

Definition at line 64 of file ossimEllipsoid.cpp.

References computeFlattening(), ossimEllipsoidFactory::findEpsgCode(), ossimEllipsoidFactory::instance(), theCode, theEccentricitySquared, theEpsgCode, and theFlattening.

   :
      theName(name),
      theCode(code),
      theEpsgCode(epsg_code),
      theA(a),
      theB(b),
      theA_squared(a*a),
      theB_squared(b*b)
{
   if (theEpsgCode == 0)
   {
      theEpsgCode = ossimEllipsoidFactory::instance()->findEpsgCode(theCode);
   }

   computeFlattening();   
   theEccentricitySquared = 2*theFlattening - theFlattening*theFlattening;
}

ossimEllipsoid() [3/4]

ossimEllipsoid::ossimEllipsoid	(	const double &	major_axis,
		const double &	minor_axis
	)

Definition at line 98 of file ossimEllipsoid.cpp.

References computeFlattening(), ossimEllipsoidFactory::instance(), theA, theB, theEccentricitySquared, theFlattening, and ossimEllipsoidFactory::wgs84().

   :
      theName(""), // initialize to empty
      theCode(""),
      theEpsgCode(0),
      theA(a),
      theB(b),
      theA_squared(a*a),
      theB_squared(b*b)
{
   // First check if this is just WGS84:
   const ossimEllipsoid* wgs84 = ossimEllipsoidFactory::instance()->wgs84();
   if ((theA == wgs84->theA) && (theB == wgs84->theB))
   {
      *this = *wgs84;
   }
   else
   {
      computeFlattening();
      theEccentricitySquared = 2*theFlattening - theFlattening*theFlattening;
   }
}

ossimEllipsoid() [4/4]

ossimEllipsoid::ossimEllipsoid

(

)

Definition at line 87 of file ossimEllipsoid.cpp.

References ossimEllipsoidFactory::instance(), and ossimEllipsoidFactory::wgs84().

{
   const ossimEllipsoid* ellipse = ossimEllipsoidFactory::instance()->wgs84();
   
   *this = *ellipse;
}

~ossimEllipsoid()

virtual ossimEllipsoid::~ossimEllipsoid ( )

inlinevirtual

Definition at line 55 of file ossimEllipsoid.h.

{};

Member Function Documentation

a()

const double& ossimEllipsoid::a ( ) const

inline

Definition at line 63 of file ossimEllipsoid.h.

Referenced by ossimUpspt::convertFromGeodetic(), ossimUtmpt::convertFromGround(), ossimUtmpt::convertToGround(), ossimSpaceObliqueMercatorProjection::setParameters(), ossimWgs72Datum::shiftFromWgs84(), ossimWgs72Datum::shiftToWgs84(), and ossimWriter::writeTiffTags().

{return theA;} // major axis

b()

const double& ossimEllipsoid::b ( ) const

inline

Definition at line 64 of file ossimEllipsoid.h.

Referenced by ossimUpspt::convertFromGeodetic(), and ossimWriter::writeTiffTags().

{return theB;} // minor axis

code()

const ossimString& ossimEllipsoid::code ( ) const

inline

Definition at line 61 of file ossimEllipsoid.h.

Referenced by ossimDatumFactory::writeCStructure().

{return theCode;}

computeFlattening()

void ossimEllipsoid::computeFlattening ( )

inlineprotected

Definition at line 186 of file ossimEllipsoid.h.

Referenced by loadState(), and ossimEllipsoid().

   {
      theFlattening = (theA - theB)/theA;
   }

computeLocalToWorldTransformFromXYZ()

void ossimEllipsoid::computeLocalToWorldTransformFromXYZ	(	double	x,
		double	y,
		double	z,
		ossimMatrix4x4 &	localToWorld
	)		const

Definition at line 670 of file ossimEllipsoid.cpp.

References ossimMatrix4x4::createIdentity(), ossimMatrix4x4::getData(), x, and y.

{
   localToWorld = ossimMatrix4x4::createIdentity();
   NEWMAT::Matrix& m = localToWorld.getData();

   // put in the translation
   m[0][3] = x;
   m[1][3] = y;
   m[2][3] = z;
   


    // normalize X,Y,Z
    double inverse_length = 1.0/sqrt(x*x + y*y + z*z);
    
    x *= inverse_length;
    y *= inverse_length;
    z *= inverse_length;

    double length_XY = sqrt(x*x + y*y);
    double inverse_length_XY = 1.0/length_XY;

    // Vx = |(-Y,X,0)|
    m[0][0] = -y*inverse_length_XY;
    m[1][0] = x*inverse_length_XY;
    m[2][0] = 0.0;

    // Vy = /(-Z*X/(sqrt(X*X+Y*Y), -Z*Y/(sqrt(X*X+Y*Y),sqrt(X*X+Y*Y))| 
    double Vy_x = -z*x*inverse_length_XY;
    double Vy_y = -z*y*inverse_length_XY;
    double Vy_z = length_XY;
    inverse_length = 1.0/sqrt(Vy_x*Vy_x + Vy_y*Vy_y + Vy_z*Vy_z);            
    m[0][1] = Vy_x*inverse_length;
    m[1][1] = Vy_y*inverse_length;
    m[2][1] = Vy_z*inverse_length;

    // Vz = (X,Y,Z)
    m[0][2] = x;
    m[1][2] = y;
    m[2][2] = z;
   
}

eccentricity()

double ossimEllipsoid::eccentricity ( ) const

inline

Definition at line 78 of file ossimEllipsoid.h.

Referenced by ossimSpaceObliqueMercatorProjection::setParameters().

{ return std::sqrt(theEccentricitySquared); }

eccentricitySquared()

double ossimEllipsoid::eccentricitySquared ( ) const

inline

Definition at line 74 of file ossimEllipsoid.h.

Referenced by XYZToLatLonHeight().

{ return theEccentricitySquared; }

evaluate()

double ossimEllipsoid::evaluate

(

const ossimEcefPoint &

location

)

const

METHOD: evaluate() evaluate will evalate the function at location x, y, z (ECEF).

Definition at line 312 of file ossimEllipsoid.cpp.

References theA_squared, theB_squared, ossimEcefPoint::x(), ossimEcefPoint::y(), and ossimEcefPoint::z().

{
   //***
   // get the axis
   //***
   return (((location.x() * location.x())/theA_squared) +
           ((location.y() * location.y())/theA_squared) +
           ((location.z() * location.z())/theB_squared) - 1.0);   
}

flattening()

double ossimEllipsoid::flattening ( ) const

inline

Definition at line 76 of file ossimEllipsoid.h.

Referenced by ossimUtmpt::convertFromGround(), ossimUtmpt::convertToGround(), ossimWgs72Datum::shiftFromWgs84(), and ossimWgs72Datum::shiftToWgs84().

{ return theFlattening; }

geodeticRadii()

void ossimEllipsoid::geodeticRadii	(	const double &	latitude,
		ossimDpt &	radii
	)		const

Computes the "geodetic" radius of curvature of the ellipsoid in the east-west (x) and north-south (y) directions for a given latitude in DEGREES:

Definition at line 559 of file ossimEllipsoid.cpp.

References ossim::cosd(), ossim::sind(), theA_squared, theB_squared, ossimDpt::x, and ossimDpt::y.

Referenced by ossimGpt::metersPerDegree().

{
   double cos_lat = ossim::cosd(lat);
   double sin_lat = ossim::sind(lat);
   double cos2_lat = cos_lat*cos_lat;
   double sin2_lat = sin_lat*sin_lat;
   double H = theA_squared*cos2_lat + theB_squared*sin2_lat;
   double H3 = H*H*H;

   radii.x = theA_squared/sqrt(H);
   radii.y = theA_squared*theB_squared/sqrt(H3);
}

geodeticRadius()

double ossimEllipsoid::geodeticRadius

(

const double &

latitude

)

const

Computes the "geodetic" radius for a given latitude in DEGREES:

Definition at line 542 of file ossimEllipsoid.cpp.

References ossim::cosd(), ossim::sind(), theA_squared, and theB_squared.

Referenced by ossimGpt::metersPerDegree(), and ossimInfo::mtrsPerDeg().

{
   double cos_lat = ossim::cosd(lat);
   double sin_lat = ossim::sind(lat);
   double cos2_lat = cos_lat*cos_lat;
   double sin2_lat = sin_lat*sin_lat;
   double a2_cos = theA_squared*cos_lat;
   double b2_sin = theB_squared*sin_lat;
   
   return sqrt( ( (a2_cos*a2_cos) + (b2_sin*b2_sin) )/ (theA_squared*cos2_lat + theB_squared*sin2_lat));
}

getA()

const double& ossimEllipsoid::getA ( ) const

inline

Definition at line 66 of file ossimEllipsoid.h.

Referenced by ossimMapProjection::getA(), ossimMapProjection::print(), ossimWgs72Datum::shift(), ossimSevenParamDatum::shift(), ossimThreeParamDatum::shiftFromWgs84(), ossimThreeParamDatum::shiftToWgs84(), ossimNewZealandMapGridProjection::update(), ossimUpsProjection::update(), ossimBonneProjection::update(), ossimCassiniProjection::update(), ossimStereographicProjection::update(), ossimEckert6Projection::update(), ossimGnomonicProjection::update(), ossimPolarStereoProjection::update(), ossimTransMercatorProjection::update(), ossimUtmProjection::update(), ossimEckert4Projection::update(), ossimMillerProjection::update(), ossimVanDerGrintenProjection::update(), ossimMollweidProjection::update(), ossimTransCylEquAreaProjection::update(), ossimPolyconicProjection::update(), ossimCylEquAreaProjection::update(), ossimMercatorProjection::update(), ossimSinusoidalProjection::update(), ossimOrthoGraphicProjection::update(), ossimAzimEquDistProjection::update(), ossimObliqueMercatorProjection::update(), ossimEquDistCylProjection::update(), ossimLambertConformalConicProjection::update(), and ossimAlbersProjection::update().

{return theA;}

getB()

const double& ossimEllipsoid::getB ( ) const

inline

Definition at line 67 of file ossimEllipsoid.h.

Referenced by ossimMapProjection::getB(), ossimMapProjection::print(), ossimWgs72Datum::shift(), and ossimSevenParamDatum::shift().

{return theB;}

getEpsgCode()

ossim_uint32 ossimEllipsoid::getEpsgCode

(

)

const

Definition at line 714 of file ossimEllipsoid.cpp.

References ossimString::empty(), ossimEllipsoidFactory::findEpsgCode(), ossimEllipsoidFactory::instance(), theCode, and theEpsgCode.

Referenced by ossimGeoTiff::writeTags(), and ossimWriter::writeTiffTags().

{
   if (!theCode.empty() && (theEpsgCode == 0))
      theEpsgCode = ossimEllipsoidFactory::instance()->findEpsgCode(theCode);
   return theEpsgCode;
}

getFlattening()

const double& ossimEllipsoid::getFlattening ( ) const

inline

Definition at line 68 of file ossimEllipsoid.h.

Referenced by ossimMapProjection::getF(), ossimThreeParamDatum::shiftFromWgs84(), ossimThreeParamDatum::shiftToWgs84(), ossimUpsProjection::update(), ossimCassiniProjection::update(), ossimStereographicProjection::update(), ossimBonneProjection::update(), ossimEckert6Projection::update(), ossimGnomonicProjection::update(), ossimPolarStereoProjection::update(), ossimTransMercatorProjection::update(), ossimUtmProjection::update(), ossimVanDerGrintenProjection::update(), ossimMillerProjection::update(), ossimEckert4Projection::update(), ossimMollweidProjection::update(), ossimPolyconicProjection::update(), ossimTransCylEquAreaProjection::update(), ossimCylEquAreaProjection::update(), ossimMercatorProjection::update(), ossimSinusoidalProjection::update(), ossimOrthoGraphicProjection::update(), ossimAzimEquDistProjection::update(), ossimObliqueMercatorProjection::update(), ossimEquDistCylProjection::update(), ossimLambertConformalConicProjection::update(), and ossimAlbersProjection::update().

{return theFlattening;}

gradient() [1/2]

void ossimEllipsoid::gradient	(	const ossimEcefPoint &	location,
		ossimEcefVector &	result
	)		const

METHOD: gradient() Compute the partials along location x, y, and z and place the result in the result vector.

Definition at line 328 of file ossimEllipsoid.cpp.

References theA_squared, theB_squared, ossimEcefPoint::x(), ossimEcefVector::x(), ossimEcefPoint::y(), ossimEcefVector::y(), ossimEcefPoint::z(), and ossimEcefVector::z().

Referenced by gradient(), and ossimRpcModel::imagingRay().

{
   result.x() = (2.0*location.x())/theA_squared;
   result.y() = (2.0*location.y())/theA_squared;
   result.z() = (2.0*location.z())/theB_squared;
}

gradient() [2/2]

ossimEcefVector ossimEllipsoid::gradient

(

const ossimEcefPoint &

loc

)

const

Definition at line 343 of file ossimEllipsoid.cpp.

References gradient().

{
   ossimEcefVector result;
   gradient(location, result);
   return result;
}

isEqualTo()

bool ossimEllipsoid::isEqualTo ( const ossimEllipsoid &  rhs, ossimCompareType  compareType = OSSIM_COMPARE_FULL  ) const

inlinevirtual

Definition at line 203 of file ossimEllipsoid.h.

References ossim::almostEqual(), theA, theB, theCode, theEccentricitySquared, theEpsgCode, theFlattening, and theName.

Referenced by ossimDatum::isEqualTo(), and ossimMapProjection::isEqualTo().

{
   return ((theName == rhs.theName)&&
           (theCode == rhs.theCode)&&
           (theEpsgCode ==rhs.theEpsgCode)&&
           ossim::almostEqual(theA, rhs.theA)&&
           ossim::almostEqual(theB, rhs.theB)&&
           ossim::almostEqual(theFlattening, rhs.theFlattening)&&
           ossim::almostEqual(theEccentricitySquared, rhs.theEccentricitySquared));
}

jacobianWrtEcef()

void ossimEllipsoid::jacobianWrtEcef	(	const ossimEcefPoint &	location,
		NEWMAT::Matrix &	jMat
	)		const

METHOD: jacobianWrtEcef() Forms Jacobian of partials of geodetic WRT ECF.

Definition at line 467 of file ossimEllipsoid.cpp.

References prinRadiiOfCurv(), RAD_PER_DEG, ossimEcefPoint::x(), XYZToLatLonHeight(), ossimEcefPoint::y(), and ossimEcefPoint::z().

Referenced by ossimPositionQualityEvaluator::computeElevAzim(), and ossimRpcModel::getForwardDeriv().

{
   double primeVert;
   double merRadius;
   double lat, lon, hgt;
   
   XYZToLatLonHeight(location.x(), location.y(), location.z(), lat, lon, hgt);
   prinRadiiOfCurv(location, merRadius, primeVert);
   
   double sinPhi = sin(lat*RAD_PER_DEG);
   double cosPhi = cos(lat*RAD_PER_DEG);
   double sinLam = sin(lon*RAD_PER_DEG);
   double cosLam = cos(lon*RAD_PER_DEG);
   double N_plus_h = primeVert + hgt;
   double M_plus_h = merRadius + hgt;
   
   jMat(1,1) = -sinPhi * cosLam / M_plus_h;
   jMat(2,1) = -sinLam / (cosPhi * N_plus_h);
   jMat(3,1) = cosPhi * cosLam;
   jMat(1,2) = -sinPhi * sinLam / M_plus_h;
   jMat(2,2) =  cosLam / (cosPhi * N_plus_h);
   jMat(3,2) = cosPhi * sinLam;
   jMat(1,3) = cosPhi / M_plus_h;
   jMat(2,3) = 0.0;
   jMat(3,3) = sinPhi;
}

jacobianWrtGeo()

void ossimEllipsoid::jacobianWrtGeo	(	const ossimEcefPoint &	location,
		NEWMAT::Matrix &	jMat
	)		const

METHOD: jacobianWrtGeo() Forms Jacobian of partials of ECF WRT geodetic.

Definition at line 507 of file ossimEllipsoid.cpp.

References prinRadiiOfCurv(), RAD_PER_DEG, ossimEcefPoint::x(), XYZToLatLonHeight(), ossimEcefPoint::y(), and ossimEcefPoint::z().

{
   double primeVert;
   double merRadius;
   double lat, lon, hgt;
   
   XYZToLatLonHeight(location.x(), location.y(), location.z(), lat, lon, hgt);
   prinRadiiOfCurv(location, merRadius, primeVert);
   
   double sinPhi = sin(lat*RAD_PER_DEG);
   double cosPhi = cos(lat*RAD_PER_DEG);
   double sinLam = sin(lon*RAD_PER_DEG);
   double cosLam = cos(lon*RAD_PER_DEG);
   double N_plus_h = primeVert + hgt;
   double M_plus_h = merRadius + hgt;
   
   jMat(1,1) = -M_plus_h * sinPhi * cosLam;
   jMat(2,1) = -M_plus_h * sinPhi * sinLam;
   jMat(3,1) =  M_plus_h * cosPhi;
   jMat(1,2) = -N_plus_h * cosPhi * sinLam;
   jMat(2,2) =  N_plus_h * cosPhi * cosLam;
   jMat(3,2) = 0.0;
   jMat(1,3) = cosPhi * cosLam;
   jMat(2,3) = cosPhi * sinLam;
   jMat(3,3) = sinPhi;
}

latLonHeightToXYZ()

void ossimEllipsoid::latLonHeightToXYZ	(	double	lat,
		double	lon,
		double	height,
		double &	x,
		double &	y,
		double &	z
	)		const

Definition at line 572 of file ossimEllipsoid.cpp.

References ossim::cosd(), ossim::sind(), theA, theEccentricitySquared, x, and y.

Referenced by ossimEcefPoint::ossimEcefPoint().

{
    double sin_latitude = ossim::sind(lat);
    double cos_latitude = ossim::cosd(lat);
    double N = theA / sqrt( 1.0 - theEccentricitySquared*sin_latitude*sin_latitude);
    x = (N+height)*cos_latitude*ossim::cosd(lon);
    y = (N+height)*cos_latitude*ossim::sind(lon);
    z = (N*(1-theEccentricitySquared)+height)*sin_latitude;
}

loadState()

bool ossimEllipsoid::loadState	(	const ossimKeywordlist &	kwl,
		const char *	prefix = 0
	)

Definition at line 351 of file ossimEllipsoid.cpp.

References computeFlattening(), ossimEllipsoidFactory::create(), ossimKeywordNames::ELLIPSE_CODE_KW, ossimKeywordNames::ELLIPSE_EPSG_CODE_KW, ossimKeywordlist::find(), ossimEllipsoidFactory::instance(), ossimKeywordNames::MAJOR_AXIS_KW, theA, theA_squared, theB, theB_squared, theCode, theEpsgCode, theName, ossimString::toDouble(), ossimString::toUInt32(), and ossimEllipsoidFactory::wgs84().

Referenced by ossimMapProjection::loadState().

{
   const char* lookup = kwl.find(prefix, ossimKeywordNames::ELLIPSE_CODE_KW);
   bool foundCode = false;
   if(lookup)
   {
      const ossimEllipsoid* ellipse = ossimEllipsoidFactory::instance()->create(ossimString(lookup));

      if(ellipse)
      {
         foundCode = true;
         *this = *ellipse;
      }
   }

   lookup = kwl.find(prefix, ossimKeywordNames::ELLIPSE_EPSG_CODE_KW);
   if (lookup)
   {
      theEpsgCode = ossimString(lookup).toUInt32();
   }

   if(!foundCode)
   {     
      const char* majorAxis = kwl.find(prefix,
                                       ossimKeywordNames::MAJOR_AXIS_KW);
      const char* minorAxis = kwl.find(prefix,
                                       ossimKeywordNames::MAJOR_AXIS_KW);

      theName = "";
      theCode = "";
      if(majorAxis && minorAxis)
      {
         theA = ossimString(majorAxis).toDouble();
         theB = ossimString(minorAxis).toDouble();

         computeFlattening();
         theA_squared = theA*theA;
         theB_squared = theB*theB;
      }
      else
      {
         const ossimEllipsoid* ellipse = ossimEllipsoidFactory::instance()->wgs84();
         
         *this = *ellipse;
      }      
   }

   return true;
}

name()

const ossimString& ossimEllipsoid::name ( ) const

inline

ACCESS METHOD...

Definition at line 60 of file ossimEllipsoid.h.

Referenced by ossimInfo::printDatums().

{return theName;}

nearestIntersection() [1/2]

bool ossimEllipsoid::nearestIntersection	(	const ossimEcefRay &	ray,
		ossimEcefPoint &	rtnPt
	)		const

METHOD: nearestIntersection() Returns the point of nearest intersection of the ray with the ellipsoid. The first version performs the intersection at the ellipsoid surface. The second version computes the ray's intersection with a surface at some offset outside (for positive offset) of the ellipsoid (think elevation).

Definition at line 126 of file ossimEllipsoid.cpp.

Referenced by ossimEcefRay::intersectAboveEarthEllipsoid().

{
   return nearestIntersection(ray, 0.0, rtnPt);
}

nearestIntersection() [2/2]

bool ossimEllipsoid::nearestIntersection	(	const ossimEcefRay &	ray,
		const double &	offset,
		ossimEcefPoint &	rtnPt
	)		const

Definition at line 178 of file ossimEllipsoid.cpp.

{
   static const char MODULE[] = "ossimEllipsoid::nearestIntersection";
   if (traceExec())
   {
      ossimNotify(ossimNotifyLevel_DEBUG) << "DEBUG: " << MODULE << ", entering...\n";
   }

   bool success = false;

   const double eccSqComp = 1.0 - theEccentricitySquared;
   const double CONVERGENCE_THRESHOLD = 0.0001;
   const int    MAX_NUM_ITERATIONS    = 10;

   //***
   // get the origin and direction of ray:
   //***
   ossimEcefPoint  start = ray.origin();   
   ossimEcefVector direction = ray.direction();
   
   double start_x = start.x();
   double start_y = start.y();
   double start_z = start.z();

   double direction_x = direction.x();
   double direction_y = direction.y();
   double direction_z = direction.z();

   ossimGpt rayGpt( start );

   int iterations = 0;
   bool done = false;
   do
   {
      double rayLat    = rayGpt.latd();
      double raySinLat = ossim::sind( rayLat );
      double rayScale  = 1.0 / sqrt( 1.0 - theEccentricitySquared * raySinLat * raySinLat );
      double rayN      = theA * rayScale;

      double A_offset = rayN + offset;
      double B_offset = rayN * eccSqComp + offset;

      double A_offset_inv = 1.0 / A_offset;
      double B_offset_inv = 1.0 / B_offset;

      double scaled_x = start_x * A_offset_inv;
      double scaled_y = start_y * A_offset_inv;
      double scaled_z = start_z * B_offset_inv;

      double A_over_B = A_offset * B_offset_inv;

      //***
      // Solve the coefficients of the quadratic formula
      //***

      double a = (direction_x*direction_x + direction_y*direction_y) * A_offset_inv;
      a += (direction_z*direction_z * B_offset_inv * A_over_B);

      double b = 2.0 * ( scaled_x*direction_x + scaled_y*direction_y +
                         scaled_z*direction_z*A_over_B );

      double c = scaled_x*start_x + scaled_y*start_y;
      c += (scaled_z*start_z * A_over_B);
      c -= A_offset;

      //***
      // solve the quadratic
      //***
      double root = b*b - 4.0*a*c;
      if ( root < 0.0 )
      {
         return false;
      }

      double squareRoot = sqrt(root);
      double oneOver2a  = 1.0 / (2.0*a);

      double t1 = (-b + squareRoot) * oneOver2a;
      double t2 = (-b - squareRoot) * oneOver2a;
      
      //***
      // sort t1 and t2 and take the nearest intersection if they
      // are in front of the ray.
      //***
//      if ( t2 < t1 )
//      {
//         double temp = t1;
//         t1 = t2;
//         t2 = temp;
//      }
//
//      double tEstimate = ( t1 > 0.0 ) ? t1 : t2;

      // OLK: Alternate means to find closest intersection, not necessarily "in front of" origin:
      double tEstimate = t1;
      if (fabs(t2) < fabs(t1))
         tEstimate = t2;

      // Get estimated intersection point.
      ossimEcefPoint rayEcef = ray.extend( tEstimate );

      rayGpt = ossimGpt( rayEcef );
      double offsetError = fabs( rayGpt.height() - offset );
      if ( offsetError < CONVERGENCE_THRESHOLD )
      {
         done = true;
         success = true;
         rtnPt = rayEcef;
      }

   }  while ( (!done) && (iterations++ < MAX_NUM_ITERATIONS) );

   if (iterations >= MAX_NUM_ITERATIONS)
   {
      if(traceDebug())
      {
         ossimNotify(ossimNotifyLevel_WARN)
            << "WARNING ossimEllipsoid::nearestIntersection: Max number of iterations reached"
            << " solving for intersection point. Result is probably inaccurate." << std::endl;
      }
   }

   return success; 
}

operator!=()

bool ossimEllipsoid::operator!= ( const ossimEllipsoid &  rhs ) const

inline

Definition at line 166 of file ossimEllipsoid.h.

References theA, theB, theCode, theFlattening, and theName.

   {
      return ( (theName != rhs.theName)||
               (theCode != rhs.theCode)||
               (theA    != rhs.theA)||               
               (theB    != rhs.theB)||
               (theFlattening != rhs.theFlattening));
   }

operator=()

const ossimEllipsoid & ossimEllipsoid::operator=

(

const ossimEllipsoid &

copy_me

)

Definition at line 721 of file ossimEllipsoid.cpp.

References theA, theA_squared, theB, theB_squared, theCode, theEccentricitySquared, theEpsgCode, theFlattening, and theName.

{
   if (this != &copy_me)
   {
      theName = copy_me.theName;
      theCode = copy_me.theCode;
      theEpsgCode = copy_me.theEpsgCode;
      theA = copy_me.theA;  
      theB = copy_me.theB;  
      theFlattening = copy_me.theFlattening;
      theA_squared = copy_me.theA_squared;
      theB_squared = copy_me.theB_squared;
      theEccentricitySquared = copy_me.theEccentricitySquared;
   }
   return *this;
}

operator==()

bool ossimEllipsoid::operator== ( const ossimEllipsoid &  rhs ) const

inline

Definition at line 157 of file ossimEllipsoid.h.

References theA, theB, theCode, theFlattening, and theName.

   {
      return ( (theName == rhs.theName)&&
               (theCode == rhs.theCode)&&
               (theA    == rhs.theA)&&
               (theB    == rhs.theB)&&
               (theFlattening == rhs.theFlattening));
   }

prinRadiiOfCurv()

void ossimEllipsoid::prinRadiiOfCurv	(	const ossimEcefPoint &	location,
		double &	merRadius,
		double &	primeVert
	)		const

METHOD: prinRadiiOfCurv() Computes the meridional radius and prime vertical at given point.

Definition at line 442 of file ossimEllipsoid.cpp.

References RAD_PER_DEG, theA, theEccentricitySquared, ossimEcefPoint::x(), XYZToLatLonHeight(), ossimEcefPoint::y(), and ossimEcefPoint::z().

Referenced by jacobianWrtEcef(), and jacobianWrtGeo().

{
   double lat, lon, hgt;
   XYZToLatLonHeight(location.x(), location.y(), location.z(), lat, lon, hgt);
   
   double sinPhi = sin(lat*RAD_PER_DEG);
   double phiFac = 1.0 - theEccentricitySquared*sinPhi*sinPhi;
   primeVert = theA / sqrt(phiFac);
   merRadius = theA*(1.0-theEccentricitySquared) / sqrt(phiFac*phiFac*phiFac);
}

saveState()

bool ossimEllipsoid::saveState	(	ossimKeywordlist &	kwl,
		const char *	prefix = 0
	)		const

Definition at line 402 of file ossimEllipsoid.cpp.

References ossimKeywordlist::add(), ossimString::c_str(), ossimKeywordNames::ELLIPSE_CODE_KW, ossimKeywordNames::ELLIPSE_EPSG_CODE_KW, ossimKeywordNames::ELLIPSE_NAME_KW, ossimKeywordNames::MAJOR_AXIS_KW, ossimKeywordNames::MINOR_AXIS_KW, theA, theB, theCode, theEpsgCode, and theName.

Referenced by ossimMapProjection::saveState().

{
   if(theCode != "")
   {
      kwl.add(prefix,
              ossimKeywordNames::ELLIPSE_CODE_KW,
              theCode.c_str(),
              true);

      kwl.add(prefix,
              ossimKeywordNames::ELLIPSE_NAME_KW,
              theName.c_str(),
              true);
   }
   if (theEpsgCode)
   {
      kwl.add(prefix, ossimKeywordNames::ELLIPSE_EPSG_CODE_KW, theEpsgCode, true);
   }

   kwl.add(prefix,
           ossimKeywordNames::MAJOR_AXIS_KW,
           theA,
           true);
   
   kwl.add(prefix,
           ossimKeywordNames::MINOR_AXIS_KW,
           theB,
           true);

   return true;
}

setA()

void ossimEllipsoid::setA ( double  a )

inline

Definition at line 70 of file ossimEllipsoid.h.

Referenced by ossimMapProjection::setAB().

{theA = a;computeFlattening();}

setAB()

void ossimEllipsoid::setAB ( double  a, double  b  )

inline

Definition at line 72 of file ossimEllipsoid.h.

{theA = a; theB = b; computeFlattening();}

setB()

void ossimEllipsoid::setB ( double  b )

inline

Definition at line 71 of file ossimEllipsoid.h.

Referenced by ossimMapProjection::setAB().

{theB = b;computeFlattening();}

setEpsgCode()

void ossimEllipsoid::setEpsgCode ( ossim_uint32  code )

inline

Definition at line 73 of file ossimEllipsoid.h.

{theEpsgCode = code;}

XYZToLatLonHeight()

void ossimEllipsoid::XYZToLatLonHeight	(	double	x,
		double	y,
		double	z,
		double &	lat,
		double &	lon,
		double &	height
	)		const

Definition at line 583 of file ossimEllipsoid.cpp.

References DEG_PER_RAD, eccentricitySquared(), theA, theB, theEccentricitySquared, x, and y.

Referenced by jacobianWrtEcef(), jacobianWrtGeo(), ossimGpt::ossimGpt(), and prinRadiiOfCurv().

{

#if 1
  // Author: Norman J. Goldstein (ngoldstein@SystemSolutionsRD.com, 
//                              normvcr@telus.net)

  const double tol = 1e-15;
  const double d = sqrt(x*x + y*y);
  const int MAX_ITER = 10;

  const double a2 = theA * theA;
  const double b2 = theB * theB;
  const double pa2 = d * d * a2;
  const double qb2 = z * z * b2;
  const double ae2 = a2 * eccentricitySquared();
  const double ae4 = ae2 * ae2;

  const double c3 = -( ae4/2 + pa2 + qb2 );          // s^2
  const double c4 = ae2*( pa2 - qb2 );               // s^1
  const double c5 = ae4/4 * ( ae4/4 - pa2 - qb2 );   // s^0

  double s0 = 0.5 * (a2 + b2) * hypot( d/theA, z/theB );

  for( int iterIdx = 0; iterIdx < MAX_ITER; ++iterIdx )
  {
    const double pol = c5 + s0 * ( c4 + s0 * ( c3 + s0 * s0 ) );
    const double der = c4 + s0 * ( 2 * c3  + 4 * s0 * s0 );

    const double ds = - pol / der;
    s0 += ds;

    if( fabs( ds ) < tol * s0 )
    {
      const double t = s0 - 0.5 * (a2 + b2);
      const double x_ell = d / ( 1.0 + t/a2 );
      const double y_ell = z / ( 1.0 + t/b2 );

      height = ( d - x_ell ) * x_ell/a2 + ( z - y_ell ) * y_ell/b2;
      height /= hypot( x_ell/a2 ,  y_ell/b2 );

      lat = atan2( y_ell/b2, x_ell/a2 ) * DEG_PER_RAD;
      lon = atan2( y, x ) * DEG_PER_RAD;

      return;
    }
  }

  #else
   double d = sqrt(x*x + y*y);

   double phi2 = z / ((1 - theEccentricitySquared) * d);
   double p = 1.0;
   double phi1 = 0.0;
   double N1 = 0.0;
   double height1 = 0.0;
   int iterIdx = 0;
   const int MAX_ITER = 10;
   if (fabs(phi2) > 1e-16 )
   {
      while ( (p > 1e-17) && (iterIdx < MAX_ITER))
      {
         phi1 = phi2;
         N1 = theA / sqrt(1.0 - (theEccentricitySquared * pow(sin(phi1), 2.0)));
         height1 = (d / cos(phi1) - N1);
         phi2 = atan((z / d) * (1.0 + (theEccentricitySquared * N1 * sin(phi1)) / z));
         p = fabs(phi2 - phi1);
         ++iterIdx;
         /* printf("phi: %e   phi2: %e   p: %e  \n", phi1, phi2, p); */
      }                                                                                           
   }                                                                                                   
   else
   {                                                                                              
      phi1 = phi2;                                                                                
      N1 = theA / sqrt(1.0 - (theEccentricitySquared * pow(sin(phi1), 2.0)));                    
      height1 = (d / cos(phi1)) - N1;                                                             
   }                                                                                                   

   /* *Latitude = phi2 * 180/PI; */
   /* *Longitude = atan2(Y, X) * 180/PI; */
   lat = phi2*DEG_PER_RAD; 
   lon = atan2(y, x)*DEG_PER_RAD;                                                                
   height = height1; 
#endif
}

Member Data Documentation

theA

double ossimEllipsoid::theA

protected

Definition at line 194 of file ossimEllipsoid.h.

Referenced by isEqualTo(), latLonHeightToXYZ(), loadState(), operator!=(), operator=(), operator==(), ossimEllipsoid(), prinRadiiOfCurv(), saveState(), and XYZToLatLonHeight().

theA_squared

double ossimEllipsoid::theA_squared

protected

Definition at line 197 of file ossimEllipsoid.h.

Referenced by evaluate(), geodeticRadii(), geodeticRadius(), gradient(), loadState(), and operator=().

theB

double ossimEllipsoid::theB

protected

Definition at line 195 of file ossimEllipsoid.h.

Referenced by isEqualTo(), loadState(), operator!=(), operator=(), operator==(), ossimEllipsoid(), saveState(), and XYZToLatLonHeight().

theB_squared

double ossimEllipsoid::theB_squared

protected

Definition at line 198 of file ossimEllipsoid.h.

Referenced by evaluate(), geodeticRadii(), geodeticRadius(), gradient(), loadState(), and operator=().

theCode

ossimString ossimEllipsoid::theCode

protected

Definition at line 192 of file ossimEllipsoid.h.

Referenced by getEpsgCode(), isEqualTo(), loadState(), operator!=(), operator=(), operator==(), ossimEllipsoid(), and saveState().

theEccentricitySquared

double ossimEllipsoid::theEccentricitySquared

protected

Definition at line 199 of file ossimEllipsoid.h.

Referenced by isEqualTo(), latLonHeightToXYZ(), operator=(), ossimEllipsoid(), prinRadiiOfCurv(), and XYZToLatLonHeight().

theEpsgCode

ossim_uint32 ossimEllipsoid::theEpsgCode

mutableprotected

Definition at line 193 of file ossimEllipsoid.h.

Referenced by getEpsgCode(), isEqualTo(), loadState(), operator=(), ossimEllipsoid(), and saveState().

theFlattening

double ossimEllipsoid::theFlattening

protected

Definition at line 196 of file ossimEllipsoid.h.

Referenced by isEqualTo(), operator!=(), operator=(), operator==(), and ossimEllipsoid().

theName

ossimString ossimEllipsoid::theName

protected

Definition at line 191 of file ossimEllipsoid.h.

Referenced by isEqualTo(), loadState(), operator!=(), operator=(), operator==(), and saveState().

---

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

• ossimEllipsoid.h
• ossimEllipsoid.cpp