Why are there so few plants that live at the ground level of the tropical rainforest?

On the ground there is a little bit of sunlight that can get through the canopy of the forest

So that they can get the most rainfall from the trees

B

Are you asking about a street map usage  if so here is your answer  a street map for a very limited area could simply be a bit map or a .jpg image.  but a more general map would probably store the streets as vectors.  but you shouldn't assume that there is one way to do it