" 坐标正反算是测绘程序设计中常见的一种计算方法,主要是根据已知的坐标点及其高程,计算待求点的坐标和高程。在C语言中,我们可以通过编写相应的函数来实现这个功能。
首先,需要包含必要的头文件:
```c
#include <stdio.h>
#include <math.h>
```
然后,定义一些常量和变量:
```c
#define EARTH_RADIUS 6378.245
#define PI 3.14159265358979323846
#define MAX_ITERATIONS 100
double lat1, lon1, alt1, lat2, lon2, alt2, dLat, dLon, a, c, e, f, t, u, s;
int i;
```
接下来,编写计算坐标正反算的函数:
```c
void reverse_transformation(double lat1, double lon1, double alt1, double *lat2, double *lon2, double *alt2) {
double dLat = *lat2 - lat1;
double dLon = *lon2 - lon1;
double a = sin(dLat / 2) * sin(dLat / 2) +
cos(lat1) * cos(lat2) *
sin(dLon / 2) * sin(dLon / 2);
c = 2 * atan2(sqrt(a), sqrt(1 - a));
e = EARTH_RADIUS * (1 - c);
f = alt1 + EARTH_RADIUS * (1 - (alt1 / e));
t = (f * (1 - c)) / (a + (f * sin(lat1) * sin(lat2)) / (e * (1 - c)));
u = sqrt(t * (t - a) * (t - b) * (t - c));
s = (t + u) / (t - u);
*alt2 = (f + EARTH_RADIUS * (c * s - 1)) / (1 - c * s);
*lat2 = lat1 + dLat * s / u;
*lon2 = lon1 + dLon * s / u;
}
```
最后,编写主函数,调用上述函数并输出结果:
```c
int main() {
lat1 = 30; // 纬度1
lon1 = 120; // 经度1
alt1 = 100; // 高程1
lat2 = 31; // 纬度2
lon2 = 121; // 经度2
alt2 = 0; // 高程2
reverse_transformation(lat1, lon1, alt1, &lat2, &lon2, &alt2);
printf("纬度2: %.2lf\n", lat2);
printf("经度2: %.2lf\n", lon2);
printf("高程2: %.2lf\n", alt2);
return 0;
}
```
将以上代码编译连接后,即可运行得到结果。注意,该代码仅供参考,实际应用时可能需要根据具体需求进行调整。"