Arc mapping is like drawing a picture of the world and all the things in it. You know how you draw your street and your house on a piece of paper? That's kind of like what arc mapping is, but on a computer.
The computer makes a big map of everything, and then it can put different kinds of information on the map, like where all the trees are, where all the streets go, and where all the people live. This makes it really easy to see what's going on and where things are.
Arc mapping is really helpful because it can help people make important decisions. For example, if a city wants to build a new road, they can look at the arc map to see where the road should go so that it doesn't disrupt too many people's lives. Or if a scientist wants to study how different animals move around in the wild, they can use arc mapping to see where all the animals are going.
So basically, arc mapping is like making a big, detailed picture of the world on a computer so that people can learn more about it and make important decisions.