Shock wave: a graph layout algorithm for text analyzing

The EVOQ tool offers researchers in social sciences a set of text analysis tools relying on the post-structuralist approach. This analysis approach relies on the identification of association and opposition relations between terms (words or expressions). The so-defined graph is presented in EVOQ by a node-link diagram. The Shock Wave is a placement algorithm specifically designed to be combined with a classical force-directed algorithm to produce a graph layout which meets the interpretability needs of the text analysts while preserving efficiency on large numbers of nodes. It structures the nodes on a circular placement with transversal opposition relations to highlight oppositions within the text concepts. Beyond our use case, the interest of Shock Wave lies in the fact that it is a novel method to present graphs of text with a strong emphasis on underlying semantic fields.