In pea plants purple flowers are dominant to white flowers and yellow seeds are dominant to green seeds. A botanist crossed two pea plants with purple flowers and yellow seeds that are both heterozygous for both traits.

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

They use the si unit, or metric system its all the same thing

What’s the question here ?