Methods for visualizing transformations among related series of graphs

Abstract

A method for displaying in a coherent manner the changes over time of a web site's structure, usage, and content is disclosed. Time tubes are generated by a method of displaying a related series of graphs. Time tubes illustrate changes in a graph that undergoes one or more transformations from one state to another. The transformations are displayed using the length of the cylindrical tube, filling the length of the time tube with planar slices which represent the data at various stages of the transformations. Time tubes may encode several dimensions of the transformations simultaneously by altering the representation of size, color, and layout among the planar slices. Temporal transformations occur when web pages are added or deleted over time. Value-based transformations include node colors, which may be used to encode a specific page's usage parameter. Spatial transformations include the scaling of physical dimension as graphs expand or contract in size. The states of a graph at various times are represented as a series of related graphs. In a preferred embodiment, an inventory of all existing nodes is performed so as to generate a list of all nodes that have existed at any time. This inventory is used to produce a layout template in which each unique node is assigned a unique layout position. To produce each planar slice, the specific nodes which exist in the slice are placed at their respective positions assigned in the layout template. In another aspect, corresponding nodes in planar slices are linked, such as with translucent streamlines, in response to a user selecting a node in a planar slice by placing his cursor over the selected node, or to show clustering of two or more nodes in one planar slice into a single node in an adjacent planar slice.