There is one issue in the CalcDistanceBetweenGeoLocations function. Sometime you will get an error, "A domain error occurred.", by passing in some specific parameters.

So I added the following Code:

--reset @Distance if it is out of the range of (-1,1)

If @Distance>1

set @Distance=1

If @Distance<-1

set @Distance=-1

before

--Get distance in miles

SET @Distance = (DEGREES(ACOS(@Distance))) * 69.09

Because ACOS can be only with a value from -1 through 1.