True, it is one of the possible meanings of "la carte" (a card, a map, a menu). Be aware that when "la carte" refers to a map, it is a map of a large region or even a country. When a map refers to a city, it is called "un plan".
[Edit: Note that when talking about a menu (EN), there are two different meanings: 1) la carte (i.e., the giant listing of a restaurant's offerings which the server gives you), it can also refer to any list from which one may make choices 2) le menu (as a list of dishes which comprise a meal). These terms are not synonyms.]
The menu meaning explains the term "à la carte". The card meaning is also used in English in the term "carte blance".
Does carte indicate a large, flat piece of paper (e.g. magna carta)? Or does it just need to have a lot of information on it?
This is confusing for English speakers because card, map, and menu seem to have so little in common. In particular, a card is usually small, whereas you make carte sound big.