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Thread: Formula Help Involving Comparing Distance With Lat. Long. Reference Points

1. Formula Help Involving Comparing Distance With Lat. Long. Reference Points

Hello Everyone,

I'm stumped on this one...

Would anyone know a formula that would return the values shown in the example attached?

I'm trying to find out how many people live within 25 miles and within 50 miles of a store, but my reference points are lat.long. coordinates.

Any help would be greatly appreciated!

Thanks

2. Re: Formula Help Involving Comparing Distance With Lat. Long. Reference Points

Welcome to the forum!

Install Chip Pearson's routine as commented into a Module and my routine at the end or in another Module. Use my function to suit as shown in test sub or commented UDF.
Code:
```Sub CountLatLongLimits()
MsgBox CountLLL(25#, CDbl([C2].Value), CDbl([B2].Value), Range("H2:H10"))
End Sub

'=CountLLL(25,C2,B2,H2:H11)
Function CountLLL(L As Double, lat1 As Double, lon1 As Double, rLatLon As Range) As Double
Dim d As Double, gcd As Double, c As Range
Application.Volatile (True)
For Each c In rLatLon
'http://www.cpearson.com/excel/LatLong.aspx
gcd = GreatCircleDistance(lat1, lon1, c.Value, c.Offset(, 1).Value, True, True)
If gcd <= L Then d = d + 1
Next c
CountLLL = d
End Function```

4. Re: Formula Help Involving Comparing Distance With Lat. Long. Reference Points

Worked perfectly...thank you!!

I do have one more question though if you don't mind.

I need to run the same counts but instead of "within 25 miles" I need "within a 30 min drive"

Is there a routine built for calculating distance in "time" (I'm guessing via Google maps), instead of "miles"?