Imagine you are a soldier in a war zone and the enemy who outnumbers you is approaching. You want call for artillery cannons or air support. The relative location of the enemy is where they are in relationship to yourself. If you know your own latitude/longitude location, you can simply call for help by saying the enemy is 4000 yards to my northeast (you would probably give a bearing from true north, like 45 degrees instead of saying to the northeast) and your artillery or aircraft could calculate the actual (absolute) location of the enemy in latitude and longitude. So the big difference is that relative location is in reference to another known location while the absolute location is the actual latitude and longitude in reference to the Earth.