我只想找到一个简单的C#类,它接收起始纬度和经度以及距离并找到边界框(max lat,min lat,max lon,min lon)。在这里还有其他类似的问题,但是没有一个真正回答这个问题,那些问题不在C#中。
帮助。
答案 0 :(得分:10)
这就是你要求的。感谢Federico A. Ramponi用Python here编写原文。
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));
}
答案 1 :(得分:4)
我知道我正在复活一个两年前的问题,但是如果有人从谷歌来到这里,我已经编写了一个C#类库来完成这个以及更多。我已经创建了一个Github repository来托管代码,并且很快就会写一篇博文。
答案 2 :(得分:-1)
如果您只有起始纬度,经度和海拔高度,则没有边界框,因为您只在空间中定义了一个点。任何矩形/边界框都需要至少两个点来定义它!