My zipcode query is not returning the correct results

[Reessee]

The following query:
CREATE PROCEDURE GetDistance AS

SELECT a.ZIPCODE, a.CITY, a.STATE,
ROUND(
(ACOS(
(SIN(c.LATITUDE) * SIN(a.LATITUDE)) +
(COS(c.LATITUDE) * COS(a.LATITUDE) *
COS(a.LONGITUDE - c.LONGITUDE))
)
)
* 3963,1
) AS distance
FROM Zipcodes a, Zipcodes c
WHERE (
ACOS(
(SIN(c.LATITUDE) * SIN(a.LATITUDE)) +
(COS(c.LATITUDE) * COS(a.LATITUDE) * COS(a.LONGITUDE - c.LONGITUDE))
)
) * 3963 <= '10'
AND c.ZIPCODE='80222'
ORDER BY distance
GO
tells me that the only zipcode within 10 miles of 80222 is 80222 and if I replace 10 with 25 it offers only one additional zip code? Does anyone have any ideas why this might be happening?
Thanks so much for any suggestions anyone has to offer.

 

[PHV]

What about replacing this:
<= '10'
with this ,
<= 10

Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886

 

[Reessee]

Thank you so much for the suggestion.
Unfortunatley I still received the same answer.

 

[Golom]

Just to rule out the obvious ...

Do you know by some independent means that there are in fact other ZIP codes within 10 miles of "80222"? I don't know where "80222" is but some US ZIP codes cover a pretty big area.

[small]No! No! You're not thinking ... you're only being logical.
- Neils Bohr[/small]

 

[Reessee]

Well, that is just like something that I would do, however, I did check and found at least one other zipcode within 2.07 miles. which my code says is 23.5 miles away. (80250)

 

[PHV]

Are the LATITUDE and LONGITUDE in radians ?
Are you absolutely sure for the 3963 value ?

Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886

 

[Reessee]

Actually I have no idea if my latitude and longitude are in radians. You wouldn't have any idea how I might find out?

 

[PHV]

You wouldn't have any idea how I might find out?
What is the result of the following query ?
SELECT MIN(Latitude), MAX(Latitude), MIN(Longitude), MAX(Longitude)
FROM ZipCode

Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886

 

[Reessee]

-14.270200000000001 70.603759999999994 -176.64435 166.410291

 

[PHV]

Well, an angle's measure in radian should be between -PI and +PI ...
You may try to replace all occurrences of ?.*ITUDE with 3.1416 * ?.*ITUDE / 180

Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886

 

[Reessee]

IT WORKED!
Thank you so so so very much!