An amazing sight, or what you use to view it if you’re near-sighted.

At home I turn play into motion, while elsewhere my slightest lean may guide a machine through danger.

I spend my days inside a shoe, though rarely seen at all. Yet lose my partner just one time, and I’m no use at all.

I’m long, green, and coiled up tight, I love to drink water and spit with my might. I slither around without any feet, Helping the plants survive summer's heat.

I have cities but no houses, Forests with no leaves or trees, Oceans vast without a single drop, And mountains rising from the breeze. I can take you across the world or point you to a treasure, Yet I never move an inch, no matter what you measure. What am I?