VBA函数用于计算给定lat / lon值的Great Circle距离

时间:2015-02-16 22:05:22

标签: ms-access access-vba ms-access-2010

我试图在自定义函数中声明多个变量。以下是我到目前为止的情况:

Public Function myDistance(w As Double, x As Double, y As Double, z As Double) As Double
      myDistance = Excel.WorksheetFunction.Acos(Cos(radians(90 - w)) * Cos(radians(90 - y))) + Sin(radians(90 - w) * Sin(radians(90 - x)) * Cos(radians(y - z))) * 3958.756           
End Function

当我尝试在查询中运行该函数时,出现以下错误:

Compile Error
Sub or Function Not Defined

我怀疑是在声明变量不正确时的语法,但我不确定如何解决这个问题。我运行了一个更简单的版本,没有任何问题。见下文:

Public Function myDistance(x as double) as double
     myDistance = Excel.WorksheetFunction.Acos(x)
End Function

函数本身将用于使用纬度和经度计算两个地方之间的距离。你知道如何解决我遇到的问题吗?

谢谢。

1 个答案:

答案 0 :(得分:1)

这是我用来计算Great Circle距离的功能,由

提供

http://www.cpearson.com/excel/LatLong.aspx

Option Compare Database
Option Explicit

' ref: http://www.cpearson.com/excel/LatLong.aspx

Private Const C_RADIUS_EARTH_KM As Double = 6370.97327862
Private Const C_RADIUS_EARTH_MI As Double = 3958.73926185
Private Const C_PI As Double = 3.14159265358979

Function GreatCircleDistance(Latitude1 As Double, Longitude1 As Double, _
            Latitude2 As Double, Longitude2 As Double, _
            ValuesAsDecimalDegrees As Boolean, _
            ResultAsMiles As Boolean) As Double

Dim Lat1 As Double
Dim Lat2 As Double
Dim Long1 As Double
Dim Long2 As Double
Dim X As Long
Dim Delta As Double

If ValuesAsDecimalDegrees = True Then
    X = 1
Else
    X = 24
End If

' convert to decimal degrees
Lat1 = Latitude1 * X
Long1 = Longitude1 * X
Lat2 = Latitude2 * X
Long2 = Longitude2 * X

' convert to radians: radians = (degrees/180) * PI
Lat1 = (Lat1 / 180) * C_PI
Lat2 = (Lat2 / 180) * C_PI
Long1 = (Long1 / 180) * C_PI
Long2 = (Long2 / 180) * C_PI

' get the central spherical angle
Delta = ((2 * ArcSin(Sqr((Sin((Lat1 - Lat2) / 2) ^ 2) + _
    Cos(Lat1) * Cos(Lat2) * (Sin((Long1 - Long2) / 2) ^ 2)))))

If ResultAsMiles = True Then
    GreatCircleDistance = Delta * C_RADIUS_EARTH_MI
Else
    GreatCircleDistance = Delta * C_RADIUS_EARTH_KM
End If

End Function

Function ArcSin(X As Double) As Double
    ' VBA doesn't have an ArcSin function. Improvise.
    ArcSin = Atn(X / Sqr(-X * X + 1))
End Function