Aphysical combination of two or more substances that can be separated by physical means

A combination of substances that can be separated by physical means is called a heterogeneous mixture. Think of how oil and water can be easily separated from each other by physically pouring off the oil or how the sand and water of mud can be separated by physically drying it out. You will find a lot of heterogeneous mixtures in daily life. Even things like a salad where all of the ingredients are mixed but can be separated physically can be considered a heterogeneous mixture.

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