The 2D-extended interface (Figure 1) is a 2D space with all the nodes scattered on a single layer along the screen’s horizontal line. Children use the mouse to move left and right and enter the database through a hyperlink after they click a node.
The 3D-survey interface (Figure 2) has all the nodes gathered into five groups in the shape of cherry blossom,
which offers a clear center and polar coordinates on a flat surface. An overview function allows the children to experience two visual hierarchies, either from above or from a flat angle. Children can use the overview function to get familiar with the entire structure of the database, then they can use the mouse scroll wheel to zoom in and out. They are able
to use the mouse to go in every direction and click on specific nodes; however, processing and memorizing the theme map might increase the user’s cognitive burden. Although the 3D-route interface (Figure 3) is a 3D, cherry blossom-shaped virtual space, users can only zoom and move around nodes using the mouse scroll wheel and the keyboard in a 2D interface.
Yet because only a small amount of information is shown at one time, it is relatively easy for the children to process information.