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Home -> Community -> Mailing Lists -> Oracle-L -> RE: longitude, latitude
As Rudy Zung has stated the formula calculates distance by employing the
Pythagorean theorem.
The formula is not generalized. It looks like it calculates distances from
near Richmond Virginia. If anyone else wants to use it they need to change
the 37.615 and the -77.5465
to their own Lat/Long expressed in decimal degrees. North and east values,
south and west get negative. I'm not sure exactly where the 5329 comes
from.
Ian MacGregor
Stanford Linear Accelerator Center
ian_at_slac.stanford.edu
-----Original Message-----
From: jfedock_at_ixl.com [mailto:jfedock_at_ixl.com]
Sent: Friday, October 06, 2000 9:41 AM
To: Multiple recipients of list ORACLE-L
Subject: longitude, latitude
Hello all,
Looking for some advice on the best way to use longitude and latitude. These values are stored in a table, along with other info.
In order to get within a certain distance, our developers are using the following query. It actually runs well, with a few hints. I feel that we need to narrow down the long/lat in the where clause by a certain distance.
I'll be the first to admit I don't know much about long/lat. I'm just trying to tune this query a bit.
Anybody else out there deal with this before?
SELECT DISTINCT service_provider_id,
SQRT(((37.6715 - LATITUDE)*(37.6715 - LATITUDE) + (-77.5465 -
LONGITUDE)*(-77.5465 - LONGITUDE)) * 5329) DIST
FROM provider_search
WHERE SPECIALTY_CATEGORY_ID = 'PH'
AND ((37.6715 - LATITUDE)*(37.6715 - LATITUDE) + (-77.5465 -
LONGITUDE)*(-77.5465 -LONGITUDE)) * 5329 < 100*100
ORDER BY DIST
Thanks.
John
jfedock_at_ixl.com
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Author:
INET: jfedock_at_ixl.com
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