How to store thousands of coordinated in one column of mysql

Question

I am creating one table which has one column which supposed to store more than 5-10k coordinates at a time. I have declared it as longtext but while storing it seems missing many of the coordinates.

CREATE TABLE IF NOT EXISTS coordinates (
  id int(11) NOT NULL AUTO_INCREMENT,
  abcd_id int(11) NOT NULL,
  polygone longtext NOT NULL,
  PRIMARY KEY (id)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
COMMIT;

What changes do I need to do to store such large coordinates?