Which of these allow nutrients to diffuse from the central canal to all the osteocytes within an osteon?

The correct answer is canaliculus.
An osteon is the functional unit of the compact bone and it is mainly comprised of bone cells, called osteocytes. Each osteocyte can connect with its counterparts through a network of canals which are called canaliculi. These microscopic canals participate in the transport of nutrients and metabolic byproducts.

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