An INSET is a small map or diagram that is included within a larger map or diagram. It is typically used to provide additional detail or context to the main map. INSET maps are often used to show a zoomed-in view of a particular area, or to provide a different perspective on the same area. They can also be used to show a different type of information, such as population density or elevation. INSET maps are an important part of cartography and are used to help people better understand the information presented in a map.