// CoordinateConv.cpp: implementation of the CCoordinateConv class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "CCoordinateTranslateDemo.h"
#include "CoordinateConv.h"
#include "math.h"  // 數(shù)學(xué)庫(kù)

const double PI = 3.1415926;

// 角度轉(zhuǎn)化成弧度
inline double DTOR(double Degree)
{
	return Degree * PI / 180.0;
}

// 弧度轉(zhuǎn)化成角度
inline double RTOD(double Radian)
{
	return Radian * 180.0 / PI;
}


#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif


//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CCoordinateConv::CCoordinateConv()
{

}

CCoordinateConv::~CCoordinateConv()
{

}


// 功  能：已知起點(diǎn)經(jīng)緯度和航向（方位）、航程（距離），求終點(diǎn)經(jīng)緯度
// 輸入值：起點(diǎn)經(jīng)緯度和航向（方位）、航程（距離）
// 返回值：終點(diǎn)經(jīng)緯度(引用形式)
void CCoordinateConv::StartLatLonCSToEndLatLon(double dBeginLat,
										       double dBeginLong,
											   double dOrient,
											   double dDist,
											   double& dEndLat,
											   double& dEndLong)
{
	// 判斷值的有效性
	ASSERT(dBeginLat>=0 && dBeginLat <= 90);
	ASSERT(dBeginLong>=0 && dBeginLong <= 180);
	ASSERT(dOrient>=0 && dOrient <= 360);
	ASSERT(dDist>=0);

	// 計(jì)算終點(diǎn)緯度
	double deltaLat = dDist/1.8520 * cos(DTOR(dOrient)); // 終點(diǎn)和起點(diǎn)的緯差,單位海里
	dEndLat = dBeginLat + deltaLat/60.0;                 // 海里轉(zhuǎn)化成度,除以60

	// 計(jì)算終點(diǎn)經(jīng)度
    double DMP = 7915.70447*(log10(tan(DTOR(45+dEndLat/2.0))) - log10(tan(DTOR(45+dBeginLat/2.0))));	// 計(jì)算緯度漸長(zhǎng)率差,單位:分	
	double deltaLong = tan(DTOR(dOrient)) * DMP; // 終點(diǎn)和起點(diǎn)的經(jīng)差,單位海里
	dEndLong = dBeginLong + deltaLong/60.0;                // 海里轉(zhuǎn)化成度,除以60
}


// 功  能：已知起點(diǎn)和終點(diǎn)經(jīng)緯度，求航向（方位）、航程（距離）
// 輸入值：起點(diǎn)和終點(diǎn)經(jīng)緯度
// 返回值：終點(diǎn)經(jīng)緯度(引用形式)
void CCoordinateConv::LongLatToXY(double dBeginLat,
								  double dBeginLong,
								  double dEndLat,
								  double dEndLong,
								  double& dOrient,
								  double& dDist)
{
	// 判斷值的有效性
	ASSERT(dBeginLat>=0 && dBeginLat <= 90);
	ASSERT(dBeginLong>=0 && dBeginLong <= 180);
	ASSERT(dEndLat>=0 && dEndLat <= 180);
	ASSERT(dEndLong>=0 && dEndLong <= 180);
	
	// 計(jì)算航向(方位)
    double DMP = 7915.70447*(log10(tan(DTOR(45+dEndLat/2.0))) - log10(tan(DTOR(45+dBeginLat/2.0))));	// 計(jì)算緯度漸長(zhǎng)率差,單位:分

    double tmpdOrient = atan((dEndLong-dBeginLong)*60/DMP);  //dEndLong-dBeginLong單位是度,而DMP單位是分,故*60
	tmpdOrient = RTOD(fabs(tmpdOrient));	

	//  由于tmpdOrient的角度值在[0，90]之間，應(yīng)討論
	if(dEndLong >= dBeginLong) // 向東
	{
		if(dEndLat >= dBeginLat) // 向北[0 90] NE
		{
			dOrient = tmpdOrient;
		}                        
		else                     // 向南(90 180] SE
		{
			dOrient = 180 - tmpdOrient;
		}
	}
	else   // 向西
	{
		if(dEndLat >= dBeginLat) // 向北[270 360) NW
		{
			dOrient = 360 - tmpdOrient;
		}                        // 向南(90 180]  SW
		else
		{
			dOrient = 180 + tmpdOrient;
		}
	}


	// 計(jì)算航程(距離)
	BOOL bNear270 = IsNearRightAngle(dOrient); // 判斷是否在90/270度附近

	if(!bNear270) 
	{
		dDist = (dEndLat - dBeginLat)*60 / cos(DTOR(dOrient)) * 1.852; 
	}
	else
	{
		// 在緯度較低、緯差不大、航程不遠(yuǎn)的情況下(即dEndLat - dBeginLat 不大)，為簡(jiǎn)化計(jì)算，可用平均緯度代替中分緯度
		if(fabs(dEndLat - dBeginLat) < 5.0)   // 平均緯度 (dEndLat + dBeginLat)/2.0)
		{
			dDist = (dEndLong - dBeginLong)*60 * cos(DTOR((dEndLat + dBeginLat)/2.0)) / sin(DTOR(dOrient)) * 1.852;  		
		}
		else                                  // 中分緯度 (acos((dEndLat - dBeginLat)*60/DMP)) 
		{
			dDist = (dEndLong - dBeginLong)*60 * cos(acos((dEndLat - dBeginLat)*60/DMP)) / sin(DTOR(dOrient)) * 1.852;
		}
	}

}


// 功  能：判斷航向是否接近90/270
// 輸入值：航向
// 返回值：是否接近90/270度標(biāo)志
BOOL CCoordinateConv::IsNearRightAngle(double dOrient)
{
	BOOL bNewRightAngle = FALSE;
	// 確保dOrient在[0，360]
	if(dOrient < 0)
	{
		AfxMessageBox("航向/方位角為負(fù)值，請(qǐng)轉(zhuǎn)化成[0 360]之間");
		dOrient = 360 + int(dOrient)%360 + (dOrient - int(dOrient));
	}
	if(dOrient > 360)
	{
		AfxMessageBox("航向/方位角為大于360，請(qǐng)轉(zhuǎn)化成[0 360]之間");	
		dOrient = (int)dOrient%360 + (dOrient - int(dOrient));
	}

	// 判斷是否接近90/270
	double Angle = (int)dOrient%180;
	if((Angle > 80) && (Angle < 100) )
	{
		bNewRightAngle = TRUE;
	}
	else
	{
		bNewRightAngle = FALSE;
	}

	return bNewRightAngle;		
}