Mysql空间数据相关

[MySQL Spatial Functions for Geo-Enabled Applications](https://www.percona.com/blog/2013/10/21/using-the-new-mysql-spatial-functions-5-6-for-geo-enabled-applications/)

[Geo (proximity) Search with MySQL](http://%20http://www.arubin.org/files/geo_search.pdf)

[Extensions for Spatial Data](https://dev.mysql.com/doc/refman/5.7/en/spatial-extensions.html)

[Spatial Analysis Functions](https://dev.mysql.com/doc/refman/5.7/en/spatial-analysis-functions.html)