How energy moves through an ecosystem can be represented by... A. Food chain

B. Food web

C. Energy pyramids

D. All the above

It’s D all of the above

Where are they though?

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