pragma mark - 得到角度
- (double)getAngleLat1:(double)lat1 withLng1:(double)lng1 withLat2:(double)lat2 withLng2:(double)lng2
{
double x1 = lng1;
double y1 = lat1;
double x2 = lng2;
double y2 = lat2;
double pi = M_PI;
double w1 = y1 / 180 * pi;
double j1 = x1 / 180 * pi;
double w2 = y2 / 180 * pi;
double j2 = x2 / 180 * pi;
double ret;
if (j1 == j2) {
if (w1 > w2)
return 270; // 北半球的情况，南半球忽略
else if (w1 < w2)
return 90;
else
return -1;// 位置完全相同
}
ret = 4* pow(sin((w1 - w2) / 2), 2)- pow(
sin((j1 - j2) / 2) * (cos(w1) - cos(w2)),2);
ret = sqrt(ret);
double temp = (sin(fabs(j1 - j2) / 2) * (cos(w1) + cos(w2)));
ret = ret / temp;
ret = atan(ret) / pi * 180;
if (j1 > j2){ // 1为参考点坐标
if (w1 > w2)
ret += 180;
else
ret = 180 - ret;
} else if (w1 > w2)
ret = 360 - ret;
return ret;
}
#pragma mark - 得到方向
- (NSString *)getDirection:(double)jiaodu
{
if ((jiaodu <= 10) || (jiaodu > 350))
return @"东";
if ((jiaodu > 10) && (jiaodu <= 80))
return @"东北";
if ((jiaodu > 80) && (jiaodu <= 100))
return @"北";
if ((jiaodu > 100) && (jiaodu <= 170))
return @"西北";
if ((jiaodu > 170) && (jiaodu <= 190))
return @"西";
if ((jiaodu > 190) && (jiaodu <= 260))
return @"西南";
if ((jiaodu > 260) && (jiaodu <= 280))
return @"南";
if ((jiaodu > 280) && (jiaodu <= 350))
return @"东南";
return @"";
}
