I haven't seen it, nor am I really sure what you mean by "maps".

Don't they? I thought they called things like Earth, "Jasoom."

Sorry, read your post wrong. The way I saw it, similar to how the Tharks gave that one liquid substance so that he could understand them...the 'humans' must have done the same. But I mean, you can't translate names and places (like planet names, or city names).

Firstmate
I don't want to beat this to death as I was just sorta making a joke.
But really why is the name of a planet any different than the name
of say a body part like 'arm'? In other words 'glubgloke' means 'arm'
and 'Jasoom' is 'Earth' sooooo... Anyway the reason has nothing to
do with logic and everything to do with how the author wanted to tell
this story. My dad used to tell me all the time 'don't let the truth
interfere with the story'.

Oddly still even though there should be no martian word for Virginia
they were able to say the word Virginia... To me that and the names
of martian cities should not translate as neither 'species' should know
the others state/city/etc names. But both had a name for the other's
planet.