Meaning can be generated when information is related at a systemic level. Such a system can be an observer, but also a discourse, for example, operationalized as a set of documents. The measurement of semantics as similarity in patterns (correlations) and latent variables (factor analysis) has been enhanced by computer techniques and the use of statistics; for example, in "latent semantic analysis" This communication provides an introduction, an example, pointers to relevant software, and summarizes the choices that can be made by the analyst. Visualization (" semantic mapping") is thus made more accessible. © 2011 Elsevier Ltd.