Efficient visualization of large text corpora

Visualization is one of the important ways on how to deal with large amounts of textual data. Most frequent application of text visualization techniques is particular in cases when one needs to understand or to explain the structure and nature of large quantity of typically unlabeled and poorly structured textual data in the form of documents. The usual approach when dealing with text for visualization is first to transform the text data into some form of high dimensional data and in the second step to carry out some kind of dimensionality reduction down to two or three dimensions that allows to graphically visualize the data. There are several (but not too many) approaches and techniques offering different insights into the text data like: showing similarity structure of documents in the corpora (eg WebSOM, ThemeScape), showing time line or topic development through time in the corpora (eg ThemeRiver), showing frequent …