/*======================================================================*
*																		*
*	map?project														*
*																		*
*	Author:?niu?hongfang												*
*	Date:	2019.07.29													*		
*	Addr:	Shen?Zhen?Guangdong										*
*																		*
*=======================================================================*/
#include?“map_project.h“
#include?“math.h“

#define		E_a				6378137.0f		/*?地球緯度圈半徑?m?*/
#define		E_b				6356755.0f		/*?地球經(jīng)度圈半徑?m?*/

/*
*	note:?coordinate?ref?init.
*
*	@param1	ref
*	@param2?latitude??rad?-pi/2~pi/2
*	@param3	longitude?rad?-pi~pi
*	@param4	h		???m
*	@return	init?success/failure
*/
int?coordinate_map_ref_init（coordinate_map_t?*pref?double?lon?double?lat?double?h）
{
	double?e?e_2;
	double?f;
	double?sin_2_lat;
	double?R_lat_circle;
	double?R_lon_circle;
	double?den_prime_vertical?R_prime_vertical?omiga_2;

	if?（lat?>?M_PI_F?/?2?||?lat?		return?-1;
	}

	f?=?（E_a?-?E_b）?/?E_a;
	e_2?=?f?*?（2.0?-?f）;
	sin_2_lat?=?sin（lat）;

	omiga_2?=?1?-?e_2?*?sin_2_lat;
	den_prime_vertical?=?sqrtf（omiga_2）;
	R_prime_vertical?=?E_a?/?den_prime_vertical;

	R_lat_circle?=?（R_prime_vertical?+?h）?*?cosf（lat）;
	R_lon_circle?=?R_prime_vertical?*?（1?-?e_2）?/?omiga_2?+?h;

	pref->h_lat?=?lat;
	pref->h_lon?=?lon;
	pref->dx_mue?=?R_lon_circle;
	pref->dy_lambda?=?R_lat_circle;
	pref->inited?=?1;

	return?0;
}

int?coordinate_map_project（const?coordinate_map_t?*pref?double?lon?double?lat?float?*x?float?*y）
{
	if?（!pref->inited）{
		return?-1;
	}

	*x?=?pref->dx_mue?*?lon;
	*y?=?pref->dy_lambda?*?lat;

	return?0;
}

int?coordinate_map_reproject（const?coordinate_map_t?*pref?float?x?float?y?double?*lon?double?*lat）
{
	if?（!pref->inited）{
		return?-1;
	}

	*lon?=?（double）x?/?pref->dx_mue;
	*lat?=?（double）y?/?pref->dy_lambda;

	return?0;
}

int?coordinate_map_ref_distance（const?coordinate_map_t?*pref?double?lon?double?lat?float?*d_x?float?*d_y）
{
	if?（!pref->inited）{
		return?-1;
	}

	double?d_lon?d_lat;

	d_lon?=?lon?-?pref->h_lon;
	d_lat?=?lat?-?pref->h_lat;

	*d_x?=?d_lon*pref->dx_mue;
	*d_y?=?d_lat*pref->dy_lambda;

	return?0;
}

?屬性????????????大小?????日期????時(shí)間???名稱(chēng)
-----------?---------??----------?-----??----
?????文件????????2243??2019-07-29?22:15??map_project.cpp
?????文件?????????708??2019-07-29?22:11??map_project.h