Non-convex Hull

A non-convex hull is a way of shaping an outline around a set of points, allowing for indentations and holes, unlike a convex hull which always forms the tightest convex shape. Imagine wrapping a rubber band around scattered objects; if the objects are spread irregularly with indentations, the non-convex hull traces a boundary that closely follows their actual shape, including inward curves. It provides a more accurate boundary for complex or irregular data groups, capturing details that convex shapes miss. This approach is useful in areas like image analysis, geographical mapping, and data clustering where precise boundaries matter.