Why doesn't a ball roll on forever after being kicked at a soccer game

Because eventually it is going to run into a barrier that is going to cause it to come to a stop.

U because the gravity pulls it down because of its weight

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