A Parts object is a collection of the Points objects that make up the parts of a Polygon or Line object. Most Polygons or Lines are single part shapes, and have a Parts collection containing a single Points object. This represents the vertices of the shape. Multi-part shapes are used to represent multi-part features as single entities, such as the islands of Hawaii or a road that is broken into several, discontinuous segments. The Points objects returned from a Parts collection are direct references to the vertices of each part of the Line or Polygon feature. This means that you can directly access and change a Point representing an individual vertex.