Thanks a lot everyone! I had not looked on the guild news for quite a month.
Actually, I've already found quite good venus maps and I have worked on my elzevir venus map since then (but it's not finished).

I'm a scientist, so I know quite well about the harsh conditions on Venus atpollard. But my Elzevir's world is a kind of uchronia, so I stated that Venus and Mars were suited for life (but with certain conditions nevertheless). Venus and Mars are in the habitable zone and both had know an era (sometimes very short) with surface water bodies and a thicker (for Mars) or less carbonated atmosphere (for Venus).

I hope I am gonna be able to finish the map before 2012!

Again, thanks for your kind answers.