Etymology of 'cartesian'

Because of the fact that Rene Descartes developed the Cartesian coordinate system, I would think that the word Cartesian would be named after him (Des-cartes). However, I can't shake the feeling that it should be named after the Latin carta, meaning map: after all, the Cartesian system is a mapping system.

Or maybe Descartes isn't the inventor's real name, and he changed his name to that after discovering the system?

Could someone help me out here?

According to Etymonline, Cartesian is the:

…Latinized form of the name of French philosopher and mathematician René Descartes (1596-1650).

So yes, it is named after him.

Merriam-Webster shows that Cartesian is derived from the Latinised form of "Descartes", Cartesius.

If you are asking why it isn't called the "Descartesian" system. Descartes would originally have meant "of Cartes" and presumably some distant ancestor came from a village called Cartes

So when his name was latinised they dropped the 'of' part and based it on the main part - cartes