[pygame] question about scrolling the world

[Michael Fiano]

Being new to game design, I'm wondering if it's a good idea to load the
whole map data and blit the huge surface to the screen so that a lot of
it is off-screen, then moving it with an offset value for the scrolling.
Is the cpu going be busy updating off-screen pixels? Is this
inefficient? I can't think of an easier way to do it for my existing
code. Thanks.