二维尺寸到公里 javascript
2d dimensions to kilometers javascript
目前我正在做一个项目，我需要计算具有 2d 维度的 2 个位置之间的距离（以千米为单位）。
我很想看到一个 javascript 示例
我用一个例子做了一个http://jsfiddle.net/ym2sn70u/5/d f k f。我喜欢在 KM 中将响应作为字符串值。例如 50.9 公里。
我很感激
您可以使用下面描述的 3 种算法中的任何一种（用 C# 编码，可以使用类似的语法转换为 Java/Javascript）来计算地球上 2 个地理点之间的距离，以英里或公里为单位（关于： http://www.codeproject.com/Articles/884183/enRoute-Real-time-NY-City-Bus-Tracking-Web-App):
/*****************************************************************************************
Module : GIS.cs |Class Lib
Description : Calculate distance between two geo-points on surface
*****************************************************************************************
Author : Alexander Bell
Copyright : 2011-2015 Infosoft International Inc
*****************************************************************************************
using System;
namespace BusNY
{
internal enum UnitSystem { SI = 0, US = 1 }
internal static class GIS
{
#region internal: properties (read-only)
internal static double EarthRadiusKm { get {return _radiusEarthKM;} }
internal static double EarthRadiusMiles { get { return _radiusEarthMiles; } }
internal static double m2km { get { return _m2km; } }
internal static double Deg2rad { get { return _toRad; } }
#endregion
#region private: const
private const double _radiusEarthMiles = 3959;
private const double _radiusEarthKM = 6371;
private const double _m2km = 1.60934;
private const double _toRad = Math.PI / 180;
#endregion
#region Method 1: Haversine algo
/// <summary>
/// Distance between two geographic points on surface, km/miles
/// Haversine formula to calculate
/// great-circle (orthodromic) distance on Earth
/// High Accuracy, Medium speed
/// re: http://en.wikipedia.org/wiki/Haversine_formula
/// </summary>
/// <param name="Lat1">double: 1st point Latitude</param>
/// <param name="Lon1">double: 1st point Longitude</param>
/// <param name="Lat2">double: 2nd point Latitude</param>
/// <param name="Lon2">double: 2nd point Longitude</param>
/// <returns>double: distance, km/miles</returns>
internal static double DistanceHaversine(double Lat1,
double Lon1,
double Lat2,
double Lon2,
UnitSystem UnitSys ){
try {
double _radLat1 = Lat1 * _toRad;
double _radLat2 = Lat2 * _toRad;
double _dLatHalf = (_radLat2 - _radLat1) / 2;
double _dLonHalf = Math.PI * (Lon2 - Lon1) / 360;
// intermediate result
double _a = Math.Sin(_dLatHalf);
_a *= _a;
// intermediate result
double _b = Math.Sin(_dLonHalf);
_b *= _b * Math.Cos(_radLat1) * Math.Cos(_radLat2);
// central angle, aka arc segment angular distance
double _centralAngle = 2 * Math.Atan2(Math.Sqrt(_a + _b), Math.Sqrt(1 - _a - _b));
// great-circle (orthodromic) distance on Earth between 2 points
if (UnitSys == UnitSystem.SI) { return _radiusEarthKM * _centralAngle; }
else { return _radiusEarthMiles * _centralAngle; }
}
catch { throw; }
}
#endregion
#region Method 2: Spherical Law of Cosines
/// <summary>
/// Distance between two geographic points on surface, km/miles
/// Spherical Law of Cosines formula to calculate
/// great-circle (orthodromic) distance on Earth;
/// High Accuracy, Medium speed
/// re: http://en.wikipedia.org/wiki/Spherical_law_of_cosines
/// </summary>
/// <param name="Lat1">double: 1st point Latitude</param>
/// <param name="Lon1">double: 1st point Longitude</param>
/// <param name="Lat2">double: 2nd point Latitude</param>
/// <param name="Lon2">double: 2nd point Longitude</param>
/// <returns>double: distance, km/miles</returns>
internal static double DistanceSLC(double Lat1,
double Lon1,
double Lat2,
double Lon2,
UnitSystem UnitSys ){
try {
double _radLat1 = Lat1 * _toRad;
double _radLat2 = Lat2 * _toRad;
double _radLon1 = Lon1 * _toRad;
double _radLon2 = Lon2 * _toRad;
// central angle, aka arc segment angular distance
double _centralAngle = Math.Acos(Math.Sin(_radLat1) * Math.Sin(_radLat2) +
Math.Cos(_radLat1) * Math.Cos(_radLat2) * Math.Cos(_radLon2 - _radLon1));
// great-circle (orthodromic) distance on Earth between 2 points
if (UnitSys == UnitSystem.SI) { return _radiusEarthKM * _centralAngle; }
else { return _radiusEarthMiles * _centralAngle; }
}
catch { throw; }
}
#endregion
#region Method 3: Spherical Earth projection
/// <summary>
/// Distance between two geographic points on surface, km/miles
/// Spherical Earth projection to a plane formula (using Pythagorean Theorem)
/// to calculate great-circle (orthodromic) distance on Earth.
/// central angle =
/// Sqrt((_radLat2 - _radLat1)^2 + (Cos((_radLat1 + _radLat2)/2) * (Lon2 - Lon1))^2)
/// Medium Accuracy, Fast,
/// relative error less than 0.1% in search area smaller than 250 miles
/// re: http://en.wikipedia.org/wiki/Geographical_distance
/// </summary>
/// <param name="Lat1">double: 1st point Latitude</param>
/// <param name="Lon1">double: 1st point Longitude</param>
/// <param name="Lat2">double: 2nd point Latitude</param>
/// <param name="Lon2">double: 2nd point Longitude</param>
/// <returns>double: distance, km/miles</returns>
public static double DistanceSEP(double Lat1,
double Lon1,
double Lat2,
double Lon2,
UnitSystem UnitSys ){
try
{
double _radLat1 = Lat1 * _toRad;
double _radLat2 = Lat2 * _toRad;
double _dLat = (_radLat2 - _radLat1);
double _dLon = (Lon2 - Lon1) * _toRad;
double _a = (_dLon) * Math.Cos((_radLat1 + _radLat2) / 2);
// central angle, aka arc segment angular distance
double _centralAngle = Math.Sqrt(_a * _a + _dLat * _dLat);
// great-circle (orthodromic) distance on Earth between 2 points
if (UnitSys == UnitSystem.SI) { return _radiusEarthKM * _centralAngle; }
else { return _radiusEarthMiles * _centralAngle; }
}
catch { throw; }
}
#endregion
}
}
第三种算法（球形地球投影）是 fastest/simplest 算法，提供相当好的精度。
关于您编辑过的问题：Javascript 代码片段似乎没问题，但 Latitude/Longitude 格式看起来与原始 3 种算法中使用的坐标的地理坐标系 (GCS) 十进制单位不同。以下是 Europe/US（使用此网络应用程序：http://infosoft.biz/geocoder.aspx）中一些知名地点的示例十进制坐标：
大都会博物馆，纬度：40.779437/经度：-73.963244
Ακρόπολη Αθηνών，纬度：37.971532 /经度：23.725749
勃兰登堡门，纬度：52.516275 /经度：13.377704
香榭丽舍大街，纬度：48.869576/经度：2.30825
普拉多博物馆，纬度：40.413782/经度：-3.692127
Cappella Sistina，纬度：41.902947/经度：12.454484
C# 代码片段中的所有 3 个函数都已经过测试，使用这种 Lat/Lon 十进制度格式可以正常工作，结果以公里或英里计算。
关于你的附加问题（数字到字符串的转换）：你可以使用 num.toPrecision(N) 或 num.toFixed(N) javascript 函数（另外，Math.round() 可以在数学计算中也很有用。
希望这会有所帮助。最好的问候，
目前我正在做一个项目，我需要计算具有 2d 维度的 2 个位置之间的距离（以千米为单位）。
我很想看到一个 javascript 示例
我用一个例子做了一个http://jsfiddle.net/ym2sn70u/5/d f k f。我喜欢在 KM 中将响应作为字符串值。例如 50.9 公里。
我很感激
您可以使用下面描述的 3 种算法中的任何一种（用 C# 编码，可以使用类似的语法转换为 Java/Javascript）来计算地球上 2 个地理点之间的距离，以英里或公里为单位（关于： http://www.codeproject.com/Articles/884183/enRoute-Real-time-NY-City-Bus-Tracking-Web-App):
/*****************************************************************************************
Module : GIS.cs |Class Lib
Description : Calculate distance between two geo-points on surface
*****************************************************************************************
Author : Alexander Bell
Copyright : 2011-2015 Infosoft International Inc
*****************************************************************************************
using System;
namespace BusNY
{
internal enum UnitSystem { SI = 0, US = 1 }
internal static class GIS
{
#region internal: properties (read-only)
internal static double EarthRadiusKm { get {return _radiusEarthKM;} }
internal static double EarthRadiusMiles { get { return _radiusEarthMiles; } }
internal static double m2km { get { return _m2km; } }
internal static double Deg2rad { get { return _toRad; } }
#endregion
#region private: const
private const double _radiusEarthMiles = 3959;
private const double _radiusEarthKM = 6371;
private const double _m2km = 1.60934;
private const double _toRad = Math.PI / 180;
#endregion
#region Method 1: Haversine algo
/// <summary>
/// Distance between two geographic points on surface, km/miles
/// Haversine formula to calculate
/// great-circle (orthodromic) distance on Earth
/// High Accuracy, Medium speed
/// re: http://en.wikipedia.org/wiki/Haversine_formula
/// </summary>
/// <param name="Lat1">double: 1st point Latitude</param>
/// <param name="Lon1">double: 1st point Longitude</param>
/// <param name="Lat2">double: 2nd point Latitude</param>
/// <param name="Lon2">double: 2nd point Longitude</param>
/// <returns>double: distance, km/miles</returns>
internal static double DistanceHaversine(double Lat1,
double Lon1,
double Lat2,
double Lon2,
UnitSystem UnitSys ){
try {
double _radLat1 = Lat1 * _toRad;
double _radLat2 = Lat2 * _toRad;
double _dLatHalf = (_radLat2 - _radLat1) / 2;
double _dLonHalf = Math.PI * (Lon2 - Lon1) / 360;
// intermediate result
double _a = Math.Sin(_dLatHalf);
_a *= _a;
// intermediate result
double _b = Math.Sin(_dLonHalf);
_b *= _b * Math.Cos(_radLat1) * Math.Cos(_radLat2);
// central angle, aka arc segment angular distance
double _centralAngle = 2 * Math.Atan2(Math.Sqrt(_a + _b), Math.Sqrt(1 - _a - _b));
// great-circle (orthodromic) distance on Earth between 2 points
if (UnitSys == UnitSystem.SI) { return _radiusEarthKM * _centralAngle; }
else { return _radiusEarthMiles * _centralAngle; }
}
catch { throw; }
}
#endregion
#region Method 2: Spherical Law of Cosines
/// <summary>
/// Distance between two geographic points on surface, km/miles
/// Spherical Law of Cosines formula to calculate
/// great-circle (orthodromic) distance on Earth;
/// High Accuracy, Medium speed
/// re: http://en.wikipedia.org/wiki/Spherical_law_of_cosines
/// </summary>
/// <param name="Lat1">double: 1st point Latitude</param>
/// <param name="Lon1">double: 1st point Longitude</param>
/// <param name="Lat2">double: 2nd point Latitude</param>
/// <param name="Lon2">double: 2nd point Longitude</param>
/// <returns>double: distance, km/miles</returns>
internal static double DistanceSLC(double Lat1,
double Lon1,
double Lat2,
double Lon2,
UnitSystem UnitSys ){
try {
double _radLat1 = Lat1 * _toRad;
double _radLat2 = Lat2 * _toRad;
double _radLon1 = Lon1 * _toRad;
double _radLon2 = Lon2 * _toRad;
// central angle, aka arc segment angular distance
double _centralAngle = Math.Acos(Math.Sin(_radLat1) * Math.Sin(_radLat2) +
Math.Cos(_radLat1) * Math.Cos(_radLat2) * Math.Cos(_radLon2 - _radLon1));
// great-circle (orthodromic) distance on Earth between 2 points
if (UnitSys == UnitSystem.SI) { return _radiusEarthKM * _centralAngle; }
else { return _radiusEarthMiles * _centralAngle; }
}
catch { throw; }
}
#endregion
#region Method 3: Spherical Earth projection
/// <summary>
/// Distance between two geographic points on surface, km/miles
/// Spherical Earth projection to a plane formula (using Pythagorean Theorem)
/// to calculate great-circle (orthodromic) distance on Earth.
/// central angle =
/// Sqrt((_radLat2 - _radLat1)^2 + (Cos((_radLat1 + _radLat2)/2) * (Lon2 - Lon1))^2)
/// Medium Accuracy, Fast,
/// relative error less than 0.1% in search area smaller than 250 miles
/// re: http://en.wikipedia.org/wiki/Geographical_distance
/// </summary>
/// <param name="Lat1">double: 1st point Latitude</param>
/// <param name="Lon1">double: 1st point Longitude</param>
/// <param name="Lat2">double: 2nd point Latitude</param>
/// <param name="Lon2">double: 2nd point Longitude</param>
/// <returns>double: distance, km/miles</returns>
public static double DistanceSEP(double Lat1,
double Lon1,
double Lat2,
double Lon2,
UnitSystem UnitSys ){
try
{
double _radLat1 = Lat1 * _toRad;
double _radLat2 = Lat2 * _toRad;
double _dLat = (_radLat2 - _radLat1);
double _dLon = (Lon2 - Lon1) * _toRad;
double _a = (_dLon) * Math.Cos((_radLat1 + _radLat2) / 2);
// central angle, aka arc segment angular distance
double _centralAngle = Math.Sqrt(_a * _a + _dLat * _dLat);
// great-circle (orthodromic) distance on Earth between 2 points
if (UnitSys == UnitSystem.SI) { return _radiusEarthKM * _centralAngle; }
else { return _radiusEarthMiles * _centralAngle; }
}
catch { throw; }
}
#endregion
}
}
第三种算法（球形地球投影）是 fastest/simplest 算法，提供相当好的精度。
关于您编辑过的问题：Javascript 代码片段似乎没问题，但 Latitude/Longitude 格式看起来与原始 3 种算法中使用的坐标的地理坐标系 (GCS) 十进制单位不同。以下是 Europe/US（使用此网络应用程序：http://infosoft.biz/geocoder.aspx）中一些知名地点的示例十进制坐标：
大都会博物馆，纬度：40.779437/经度：-73.963244
Ακρόπολη Αθηνών，纬度：37.971532 /经度：23.725749
勃兰登堡门，纬度：52.516275 /经度：13.377704
香榭丽舍大街，纬度：48.869576/经度：2.30825
普拉多博物馆，纬度：40.413782/经度：-3.692127
Cappella Sistina，纬度：41.902947/经度：12.454484
C# 代码片段中的所有 3 个函数都已经过测试，使用这种 Lat/Lon 十进制度格式可以正常工作，结果以公里或英里计算。
关于你的附加问题（数字到字符串的转换）：你可以使用 num.toPrecision(N) 或 num.toFixed(N) javascript 函数（另外，Math.round() 可以在数学计算中也很有用。
希望这会有所帮助。最好的问候，