如何计算没有javascript的地图边界

Question

我有一个坐标列表，它将被视为地图的中心点。

我需要使用C＃（无javascript无地图对象）在缩放级别16计算地图的边界。

这可能吗？

请指教。

Answer 1

这是我想要的东西。我没有写过这个班的个人，在这里的某个地方找到了，我不记得这个学分是X人！提供纬度和经度以及KM中的半径给出了一个边界框。 GMap在视口界限上做了些什么。

  public class GlobalMercator 
      { 
       public class MapPoint 
       { 
        public double Longitude { get; set; } // In Degrees 
        public double Latitude { get; set; } // In Degrees 
       } 

       public class BoundingBox 
       { 
        public MapPoint MinPoint { get; set; } 
        public MapPoint MaxPoint { get; set; } 
       } 

       // Semi-axes of WGS-84 geoidal reference 
       private const double WGS84_a = 6378137.0; // Major semiaxis [m] 
       private const double WGS84_b = 6356752.3; // Minor semiaxis [m] 

       // 'halfSideInKm' is the half length of the bounding box you want in kilometers. 
       public static BoundingBox GetBoundingBox(MapPoint point, double halfSideInKm) 
       { 
        // Bounding box surrounding the point at given coordinates, 
        // assuming local approximation of Earth surface as a sphere 
        // of radius given by WGS84 
        var lat = Deg2rad(point.Latitude); 
        var lon = Deg2rad(point.Longitude); 
        var halfSide = 1000 * halfSideInKm; 

        // Radius of Earth at given latitude 
        var radius = WGS84EarthRadius(lat); 
        // Radius of the parallel at given latitude 
        var pradius = radius * Math.Cos(lat); 

        var latMin = lat - halfSide/radius; 
        var latMax = lat + halfSide/radius; 
        var lonMin = lon - halfSide/pradius; 
        var lonMax = lon + halfSide/pradius; 

        return new BoundingBox 
        { 
         MinPoint = new MapPoint { Latitude = Rad2deg(latMin), Longitude = Rad2deg(lonMin) }, 
         MaxPoint = new MapPoint { Latitude = Rad2deg(latMax), Longitude = Rad2deg(lonMax) } 
        }; 
       } 

       // degrees to radians 
       private static double Deg2rad(double degrees) 
       { 
        return Math.PI * degrees/180.0; 
       } 

       // radians to degrees 
       private static double Rad2deg(double radians) 
       { 
        return 180.0 * radians/Math.PI; 
       } 

       // Earth radius at a given latitude, according to the WGS-84 ellipsoid [m] 
       private static double WGS84EarthRadius(double lat) 
       { 
        // http://en.wikipedia.org/wiki/Earth_radius 
        var An = WGS84_a * WGS84_a * Math.Cos(lat); 
        var Bn = WGS84_b * WGS84_b * Math.Sin(lat); 
        var Ad = WGS84_a * Math.Cos(lat); 
        var Bd = WGS84_b * Math.Sin(lat); 
        return Math.Sqrt((An * An + Bn * Bn)/(Ad * Ad + Bd * Bd)); 
       } 
      }