如何將dbgeography中的距離返回到km？

Question

這是計算從當前位置到列表中其他地方的距離的 json 結果，但我有一個問題，我無法將距離單位（度）從 dbgeography.location.distance 轉換為 km，這是我的代碼：

 string CurrentLocation = String.Format("POINT(" + CurrentLat + " " + CurrentLng + ")", 4326);
                DbGeography point = DbGeography.PointFromText(CurrentLocation, DbGeography.DefaultCoordinateSystemId);

                var places = (from u in context.schoolinfo

                              orderby u.Location.Distance(point.Buffer(dist))

                              select u).Take(10).Select(x => new schoollinfo() { Name = x.name, Lat = x.Location.Latitude, Lng = x.Location.Longitude, Distance = x.Location.Distance(point.Buffer(dist)) }); ;

                var nearschools = places.ToList();
                return Json(nearschools, JsonRequestBehavior.AllowGet);

結果打印屏幕

Answer 1

為了計算距離，它是點（經度緯度）而不是點（緯度經度）所以代碼將更改為：

     select u).Take(10).Select(x => new schoollinfo() { Name = x.name, Lat = x.Location.Latitude, Lng = x.Location.Longitude, Distance = DbGeography.FromText("POINT(" + x.Location.Longitude + " " + x.Location.Latitude + ")", 4326).Distance(point) });