/
point_ext.go
56 lines (44 loc) · 1.15 KB
/
point_ext.go
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package ext
import (
"math"
)
// Point 经纬度
type Point struct {
Lng float64 //经度
Lat float64 //纬度
Sort int //序号
}
const (
EARTH_RADIUS = 6371393 // 地球半径,单位:米
)
func toRadians(degrees float64) float64 {
return degrees * math.Pi / 180.0
}
// GetDistance 计算两个经纬度距离,单位米
func GetDistance(lon1, lat1, lon2, lat2 float64) float64 {
if lon1 == 0 || lat1 == 0 || lon2 == 0 || lat2 == 0 {
return 0
}
lat1 = toRadians(lat1)
lon1 = toRadians(lon1)
lat2 = toRadians(lat2)
lon2 = toRadians(lon2)
dLat := lat2 - lat1
dLon := lon2 - lon1
a := math.Sin(dLat/2)*math.Sin(dLat/2) +
math.Cos(lat1)*math.Cos(lat2)*
math.Sin(dLon/2)*math.Sin(dLon/2)
c := 2 * math.Atan2(math.Sqrt(a), math.Sqrt(1-a))
return EARTH_RADIUS * c
}
// GetMultiDistance 计算多个经纬度 与 给定坐标的距离,单位米
func GetMultiDistance(lon1 float64, lat1 float64, points []*Point) map[int]float64 {
var result = make(map[int]float64, 0)
if len(points) == 0 {
return result
}
for _, point := range points {
result[point.Sort] = GetDistance(lon1, lat1, point.Lng, point.Lat)
}
return result
}