prj坐标转换

 

同一参考椭球下不同坐标系转换

投影坐标转经纬度

经纬度转投影坐标

 

头文件和宏定义

#include <proj_api.h>
#include <string>

#define RAD_TO_DEG 57.295779513082321
#define DEG_TO_RAD .017453292519943296

定义坐标系

projPJ pj_from_;
projPJ pj_to_;
 
 int zone = 51;
//UTM
 std::string to_coordinate = "+proj=utm +zone=" + std::to_string(zone) + " +ellps=WGS84 +datum=WGS84 +units=m +no_defs";
//WGS84
 std::string from_coordinate = "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs";

坐标系赋值函数

bool CoordinateConvertTool::SetConvertParam(from_coordinate,to_coordinat）
{

if (pj_from_) 
{
 　　pj_free(pj_from_);
 　　pj_from_ = nullptr;
 }
 if (pj_to_) 
 {
    pj_free(pj_to_);
    pj_to_ = nullptr;
 }

  if (!(pj_from_ = pj_init_plus(from_coordinate.c_str()))) 
　{return false;
  }

  if (!(pj_to_ = pj_init_plus(to_coordinate.c_str()))) 
  {
    pj_free(pj_from_);
    pj_from_ = nullptr;
    return false;
  }
  return true;
}

 

坐标转换函数

bool CoordinateConvertTool::CoordiateConvertToLatLong(const double utm_x, const double utm_y,
                          const double utm_z, double* longitude,
                          double* latitude, double* height_ellipsoid)
{                       
  if (!pj_from_ || !pj_to_) 
　{
　　　　return false;
  }

  double gps_longitude = utm_x;
  double gps_latitude = utm_y;
  double gps_alt = utm_z;

  if (pj_is_latlong(pj_from_)) 
  {
     gps_longitude *= DEG_TO_RAD;
     gps_latitude *= DEG_TO_RAD;
     gps_alt = utm_z;
   }

  if (0 != pj_transform(pj_from_，pj_to_, 1, 1, &gps_longitude,
                          &gps_latitude, &gps_alt)) 
  {return false;
  }

  if (pj_is_latlong(pj_to_))
 {
    gps_longitude *= RAD_TO_DEG;
    gps_latitude *= RAD_TO_DEG;
  }

  *longitude = gps_longitude;
  *latitude = gps_latitude;
  *height_ellipsoid = gps_alt;

  return ture;
}