public
class
BaiDuMap {
static
double
DEF_PI =
3.14159265359
;
// PI
static
double
DEF_2PI=
6.28318530712
;
// 2*PI
static
double
DEF_PI180=
0.01745329252
;
// PI/180.0
static
double
DEF_R =
6370693.5
;
// radius of earth
//适用于近距离
public
static
double
GetShortDistance(
double
lon1,
double
lat1,
double
lon2,
double
lat2)
{
double
ew1, ns1, ew2, ns2;
double
dx, dy, dew;
double
distance;
// 角度转换为弧度
ew1 = lon1 * DEF_PI180;
ns1 = lat1 * DEF_PI180;
ew2 = lon2 * DEF_PI180;
ns2 = lat2 * DEF_PI180;
// 经度差
dew = ew1 - ew2;
// 若跨东经和西经180 度，进行调整
if
(dew > DEF_PI)
dew = DEF_2PI - dew;
else
if
(dew < -DEF_PI)
dew = DEF_2PI + dew;
dx = DEF_R * Math.cos(ns1) * dew;
// 东西方向长度(在纬度圈上的投影长度)
dy = DEF_R * (ns1 - ns2);
// 南北方向长度(在经度圈上的投影长度)
// 勾股定理求斜边长
distance = Math.sqrt(dx * dx + dy * dy);
return
distance;
}
//适用于远距离
public
static
double
GetLongDistance(
double
lon1,
double
lat1,
double
lon2,
double
lat2)
{
double
ew1, ns1, ew2, ns2;
double
distance;
// 角度转换为弧度
ew1 = lon1 * DEF_PI180;
ns1 = lat1 * DEF_PI180;
ew2 = lon2 * DEF_PI180;
ns2 = lat2 * DEF_PI180;
// 求大圆劣弧与球心所夹的角(弧度)
distance = Math.sin(ns1) * Math.sin(ns2) + Math.cos(ns1) * Math.cos(ns2) * Math.cos(ew1 - ew2);
// 调整到[-1..1]范围内，避免溢出
if
(distance >
1.0
)
distance =
1.0
;
else
if
(distance < -
1.0
)
distance = -
1.0
;
// 求大圆劣弧长度
distance = DEF_R * Math.acos(distance);
return
distance;
}
public
static
void
main(String[] args) {
double
mLat1 =
39.90923
;
// point1纬度
double
mLon1 =
116.357428
;
// point1经度
double
mLat2 =
39.90923
;
// point2纬度
double
mLon2 =
116.397428
;
// point2经度
double
distance = BaiDuMap.GetShortDistance(mLon1, mLat1, mLon2, mLat2);
System.out.println(distance);
}
}