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我正在尝试从起点和向南和向东行驶的距离计算纬度 lng 点。我将使用什么地圈函数来计算？

new_coordinate <- nc(latitude, longitude, km_south, km_east)
new_coordinate
[1]   49.49578 -101.48574

我试过从互联网上手动计算，但似乎没有什么对我有用。我确保使用弧度。

coords <- function(cells_south, cells_east) {
  start_lat <- 52.285883
  start_lng <- -101.497821
  cells_south <- 3000
  cells_east <- 2500
  kmeast<-cells_east/10 #each cell 100 m
  kmsouth<-cells_south/10 
  #Latitude: 1 deg = 110.574 km
  #Longitude: 1 deg = 111.320*cos(latitude) km
  #lng_east <- (kmeast / (111.320 * cos(start_lat*(pi/180)))) + start_lng
  #lat_south <- start_lat - (kmsouth /110.574)
  #elevation <- dem$data[cells_south,cells_east] #elevation from ascii grid

  #Lets try calculating the distance from the north west origin
  theta <- 270 * pi /180
  cos_a = cos(theta)
  sin_a = sin(theta)
  cl <- cos(start_lat)
 # r = 100 meters.
  east_displacement = 100 * 0.5 / cl / 111111
  south_displacement = 100 * cos_a / 111111
  ret<-(c(start_lat-south_displacement,start_lng+east_displacement))

  lat1<-start_lat
  tc <- 0*pi / 270
  d<-kmsouth
  lon1 <- start_lng
  lat =asin(sin(lat1)*cos(d)+cos(lat1)*sin(d)*cos(tc))
  dlon=atan2(sin(tc)*sin(d)*cos(lat1),cos(d)-sin(lat1)*sin(lat))
  lon=(lon1-dlon +pi %% 2*pi )-pi
}

52.28588 -101.49886

认为它应该在附近

57.760 -99.764

（根据谷歌地图推测东 300 公里 250 公里。）

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