| Graydon 2006-03-19, 11:48 pm |
| A goggle search found this..it is a basic spherical astronomy
calculation:
const pi = 3. 14159265358979323846
Function distance(lat1, lon1, lat2, lon2, unit)
Dim theta, dist
theta = lon1 - lon2
dist = sin(deg2rad(lat1)) * sin(deg2rad(lat2)) + cos(deg2rad(lat1))
* cos(deg2rad(lat2)) * cos(deg2rad(theta))
dist = acos(dist)
dist = rad2deg(dist)
distance = dist * 60 * 1.1515
Select Case ucase(unit)
Case "K"
distance = distance * 1.609344
Case "N"
distance = distance * 0.8684
End Select
End Function
'
' This function get the arccos function from arctan function
'
Function acos(rad)
If Abs(rad) <> 1 Then
acos = pi/2 - Atn(rad / Sqr(1 - rad * rad))
ElseIf rad = -1 Then
acos = pi
End If
End function
'
' This function converts decimal degrees to radians
'
Function deg2rad(Deg)
deg2rad = cdbl(Deg * pi / 180)
End Function
'
' This function converts radians to decimal degrees
'
Function rad2deg(Rad)
rad2deg = cdbl(Rad * 180 / pi)
End Function
On Mon, 20 Mar 2006 00:41:17 GMT, "Marcus Fox"
<please-reply-via-newsgroup-th@-i-posted-to.com> wrote:
>Is there any program available that will give me the distance in specified
>units between two sets of latitude/longtitude coordinates? Or can someone
>perhaps explain how I can program something in Excel - have rows and colums
>of placenames listed by coordinates and the distances between them in the
>respective cells where the rows and colums converge.
>
>Marcus
>
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