Record to be stored in a tree is described by a tuple and this is represented in data object. Both the bounding rectangle for node and tuple in data object can be described by class feature. Therefore it is a has-relation between node and feature, i.e. node has feature, as shown in the Figure 12. It is the same for data and feature. Node may contain more than one feature and this is depending the fan-out of the node.
Different tree has different methods for inserting, searching and deleting a record.
The differences are implemented in different node classes. For example, R-tree uses rnode class to represent its nodes and its insert methods. VP-Tree uses class vpnode. Their internal structures are also the same. In order to have better uses on these methods, node class is used to extract these common features.