Answer:
Their not akin in any way. Atlas was the Titan who held up the sky. In that, he can be assosiated with Tyr, who is said to be the pillar of the sky, or the Irminsul of Anglo-Saxon Heathenry. Or the four dwarves Nordri, Sudri, Vestri and Estri (North, South, West, East), who hold up Ymir's Skull (the sky).
Yggdrasil is the World Tree that connects the nine worlds, with a root in three of them. A branch over every world.