https://github.com/lucasepe/lib_mysqludf_haversine

MySQL UDF to compute the Haversine formula
https://github.com/lucasepe/lib_mysqludf_haversine

distance geolocation haversine-formula mysql udf

Last synced: 2 months ago
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MySQL UDF to compute the Haversine formula

• Host: GitHub
• URL: https://github.com/lucasepe/lib_mysqludf_haversine
• Owner: lucasepe
• Archived: true
• Created: 2012-04-23T08:20:51.000Z (over 12 years ago)
• Default Branch: master
• Last Pushed: 2017-02-28T16:50:00.000Z (almost 8 years ago)
• Last Synced: 2024-07-31T22:56:00.980Z (5 months ago)
• Topics: distance, geolocation, haversine-formula, mysql, udf
• Language: C
• Size: 5.86 KB
• Stars: 46
• Watchers: 6
• Forks: 8
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

        
lib_mysqludf_haversine

======================

MySQL UDF to compute the [Haversine formula](http://en.wikipedia.org/wiki/Haversine_formula)

Returns the haversine distance from two points

Note: MySQL 5.7 introduced the native [`st_distance_sphere`](https://dev.mysql.com/doc/refman/5.7/en/spatial-convenience-functions.html#function_st-distance-sphere) function, so this project here is not required anymore.

Input parameters

----------------

lat1 (real), lng1 (real), lat2 (real), lng2 (real), type (string - optinal - 'km', 'ft', 'mi')

Output

------

Distance between the two points. The measurement is returned in kilometers (real)

by default, however if you specify the 5th *type* argument you may return in other

measurements.

Install

=======

To compile

----------

    gcc -shared -fPIC -o lib_mysqludf_haversine.so lib_mysqludf_haversine.c $(mysql_config --cflags) \

        -lm -DMYSQL_DYNAMIC_PLUGIN

To register this function

-------------------------

At mysql commandline prompt, type:

    CREATE FUNCTION haversine_distance RETURNS REAL SONAME 'lib_mysqludf_haversine.so';

To get rid of the function

--------------------------

At mysql commandline prompt, type:

    DROP FUNCTION haversine_distance;

To list all installed functions

-------------------------------

At mysql commandline prompt, type:

    SELECT  FROM mysql.func;

Troubleshooting

---------------

If you have permission problems installing function such as:

    ERROR 1126 (HY000): Can't open shared library 'lib_mysqludf_haversine.so' 

    (errno: 22 /usr/lib/mysql/plugin/lib_mysqludf_haversine.so: failed to map segment from shared object: Permission denied)

Follow this steps:

 1. type: `sudo vi /etc/apparmor.d/usr.sbin.mysqld`;

 2. add this line: `/usr/lib/mysql/plugin/** mr,` and save;

 3. type: `sudo /etc/init.d/apparmor restart`

then register the function in MySQL.

How to use

==========

Once installed, to calculate distance between two Latitude/Longitude points:

    SELECT id, name FROM MY_PLACES WHERE haversine_distance(lat1, lng1, lat2, lng2) < 40;

The `SELECT` will return all the records with a distance less then 40 kilometers.

    SELECT id, name FROM MY_PLACES WHERE haversine_distance(lat1, lng1, lat2, lng2, 'ft') < 25;

The `SELET` will return all the records with a distance less then 25 feet.