Gravity model of spatial interaction

The Gravity Model of Spatial Interaction is a way to predict and understand how and why people or goods move between places. It suggests that the interaction between two locations is influenced by their size (like population or economic activity) and the distance between them. Just as larger objects attract each other more strongly in physics, larger cities attract more people and goods, while distance can make interaction less likely. For example, people are more likely to travel between two big cities that are close together compared to a small town farther away.