The base of the pyramid is built from organisms that primarily
a) are autotrophs.
b) are heterotrophs.
c) consume organisms located above them.
d) are heterotrophic, primary consumers.

THe base of the pyramid is built from organisms that primarily
A) are autotrophs.

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