The Word Tree visualization is an interactive tool to show the different contexts in which brands or products appear. Its graph-based display facilitates the rapid exploration of search results and conveys a better understanding of how language is being used surrounding a certain topic. The module processes the list of concordances of the sentence view and presents them in a more structured manner to emphasize the usage context of a term. It complements the tag cloud, which gives a good overview of the most frequent terms, but does not reflect their usage context within specific sentences.
Visual Word Tree Representation
As an integral part of the webLyzard dashboard [1, 2], the Word Tree visualization allows to quickly grasp the major threads in a public debate. It is based on the popular keyword-in-context technique  and adopts a symmetrical approach . The search term represents the root of the word tree. The left part displays all sentence parts that occur before the search term (prefix tree), the right part those that follow the search term (suffix tree). These branches to the left and to the right help users to spot repetition in contextual expressions that precede or follow the search term. Visual cues include different font sizes to indicate the frequency of phrases, and connecting lines to highlight typical sentence structures.
Processing Steps and Word Tree Example
The Word Tree generator builds the tree-like structure by (1) searching for a term – e.g., science, (2) grouping identical phrases containing the term into nodes – e.g., political science, and (3) creating additional sub-nodes once the sentences start to differ – e.g., political science at …, political science professor …, etc. This grouping together of equal phrases into a connected word tree structure sheds light on word usage within the selected source(s) in a given time interval.
Explore and Visualize
- Hovering over a node highlights all related sentences – only a single (complete) branch in the case of leaf nodes, or all branches containing the phrase from the root to the hovered branch in the case of intermediate nodes.
- Single clicking on the root node (= a term matching the search query) displays alternative root terms, which can be used to create variations of the analysis based on the same set of search results. This is useful when searching for multiple words – e.g., clicking on a topic or using the logical “or” operator of the advanced search.
- Single clicking on intermediate nodes reprocesses the shown data to create a new graph (the phrase from the previous root to the clicked word becomes the new root). This drill down operation can be used to limit the amount of information shown, and to explore sub-branches of word trees containing a specific verb or noun.
- ‘Expand tree’ and ‘Shrink tree’ actions allow users to add or remove hierarchical layers of branches, for example to hide individual sentences and focus the display on the primary tree structure.
Word Tree References
- Scharl, A., Herring, D., Rafelsberger, W., Hubmann-Haidvogel, A., Kamolov, R., Fischl, D., Föls, M. and Weichselbraun, A. (2017). Semantic Systems and Visual Tools to Support Environmental Communication, IEEE Systems Journal, 11(2): 762-771.
- Scharl, A., Kamolov, R., Fischl, D., Rafelsberger, W. and Jones, A. (2014). Visualizing Contextual Information in Aggregated Web Content Repositories. 9th Latin American Web Congress (LA-WEB 2014). Ouro Preto, Brazil. IEEE Press. 114-118.
- Fischl, D. and Scharl, A. (2014). Metadata Enriched Visualization of Keywords in Context, 6th ACM SIGCHI Symposium on Engineering Interactive Computing Systems. Rome, Italy: Association for Computing Machinery. 193-196.
- Wattenberg, M. and Viégas, F.B. (2008). The Word Tree, an Interactive Visual Concordance, IEEE Transactions on Visualization and Computer Graphics, 14(6): 1221-1228.