Which of the following statements about viruses is true? A: A virus belongs to the Archaea Domain.
B: A virus is a single-celled organism.
C: A virus has a cell membrane made of proteins.
D: A virus can evolve.

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