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tobyprivett/haversine-php

Created May 13, 2016 20:33
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haversine-php
// php implementation from http://stackoverflow.com/questions/14750275/haversine-formula-with-php
I calculate distances straight inside queries, using the following stored procedure:
CREATE FUNCTION GEODIST (lat1 DOUBLE, lon1 DOUBLE, lat2 DOUBLE, lon2 DOUBLE)
RETURNS DOUBLE
DETERMINISTIC
BEGIN
DECLARE dist DOUBLE;
SET dist = round(acos(cos(radians(lat1))*cos(radians(lon1))*cos(radians(lat2))*cos(radians(lon2)) + cos(radians(lat1))*sin(radians(lon1))*cos(radians(lat2))*sin(radians(lon2)) + sin(radians(lat1))*sin(radians(lat2))) * 6378.8, 1);
RETURN dist;
END|
You just execute the above as an SQl statement from within phpMyAdmin to create the procedure. Just notice the ending |, so in your SQL input window, choose for the | sign as limiter.
Then in a query, call it like this:
$sql = "
SELECT `locations`.`name`, GEODIST(`locations`.`lat`, `locations`.`lon`, " . $lat_to_calculate . ", " . $lon_to_calculate . ") AS `distance`
FROM `locations` ";
I found this to be a lot faster than calculating it in PHP after the query has been run.
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