What is atp? list the three components of an atp molecule. what is atp used for?

ATP(Adenosine Triphosphate) is a small molecule used in cells as a coenzyme. It is often referred to as the "molecular unit of currency" of intracellular  energy transfer.

Three components of an ATP molecule:
      -At the centre is a sugar molecule,ribose( the same sugar that forms the basis of RNA). Attached to one side of this base(a group consisting of linked rings of carbon and nitrogen atoms) in this case the base is adenine. The other side of the sugar is attached to a string of three phosphate groups.

  ATP is used to transport chemical energy within cells for metabolism. 

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