Hi Scott
A nice approach - although I do this in my application server when querying with LINQ rather than on the database. Of course sometimes that is not practical (Like when searching large volumes of data), so having this as a backup is very useful
What I did do for my function (and recommend that you do for yours 🙂 ) is to include in the name what measurement unit it is in - the difference between functions that return values in Miles and those that return values in Kilometres comes up all over the show in bug reports. So I would call it "fn_latlondistance_mi"
Regards,
Joon