The Well-Known Text (WKT) representation of geometry values is designed
for exchanging geometry data in ASCII form. The OpenGIS specification
provides a Backus-Naur grammar that specifies the formal production
rules for writing WKT values (see
http://dev.mysql.com/doc/refman/5.7/en/spatial-extensions.html).

URL: http://dev.mysql.com/doc/refman/5.7/en/gis-data-formats.html

