Based on the nature of auxins discussed in the previous section and the explanation of photo-and geotropism, explain how auxins could cause hydrotropism.

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