The Well-Known Text (WKT) representation of Geometry is designed to
exchange geometry data in ASCII form. For a Backus-Naur grammar that
specifies the formal production rules for writing WKT values, see the
OpenGIS specification document referenced in
http://dev.mysql.com/doc/refman/5.1/en/spatial-extensions.html.

URL: http://dev.mysql.com/doc/refman/5.1/en/gis-wkt-format.html

