“…are located. Chen [15], Börner et al [11] and Dodge and Kitchin [22] discuss a variety of methods to accomplish this, ranging from traditional factor analytic [23], [41] and multidimensional scaling models [13], [47] to two-and three-dimensional tree maps [4], [5], [12], [25], [28], [46] and self-organizing maps [16], [17], [33] - [36], [48]. Several of these approaches not only address the reconstruction of the spaces and the placement of information items in them, but also attempt to partition the resultant space into distinct regions, mostly so that the regions' areas reflect the magnitude or extent of their contents; for instance, expressed as the number of items they contain.…”