Why Maps Need to Keep on Being Updated

My son has a phone which happens to have a GPS-based mapping application. Last week, he asked me (what I thought was) a very basic question: the question as to why maps need to keep on being updated. I didn’t expect this question from him (he seems to be a reasonably bright kid), or from anyone else for that matter. I had always thought that the reason as to why maps need to keep on being updated should be obvious to everyone. But my son’s question jolted me back to reality: the reality that not everyone is a mapping expert like me, and therefore, I shouldn’t expect everyone to be capable of figuring out why maps need to keep on being updated.

So, then, why is it that maps need to keep on being updated? The reason as to why maps need to keep on being updated, I told my son, is that the features on which the maps are based keep on changing. New landmarks are always coming up, even as old landmarks disappear (especially the man-made ones). Therefore, thanks to the fact that the features on which maps are based keep on changing, it follows that the maps also need to keep on being updated, to reflect the new realities on the ground.