Which statement accurately describes the rock layers?
layer 8 is older than layer 1.
layer 3 is younger than layer 6.
layer 7 and layer 4 are the same relative age.
layer 2 and layer 9 are the same relative age.

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