In this overview, commonly used dimensionality reduction techniques for data visualization and their properties are reviewed. Thereby, the focus lies on an intuitive understanding of the underlying mathematical principles rather than detailed algorithmic pipelines. Important mathematical properties of the technologies are summarized in the tabular form. The behavior of representative techniques is demonstrated for three benchmarks, followed by a short discussion on how to quantitatively evaluate these mappings. In addition, three currently active research topics are addressed: how to devise dimensionality reduction techniques for complex non-vectorial data sets, how to easily shape dimensionality reduction techniques according to the users preferences, and how to device models that are suited for big data sets.Dimensionality reduction in its original form addresses the projection of high-dimensional vectors to a low-dimensional space. Often, however, data are not given in the form of vectors, but as pairwise relations between data points. Alternatively, data can possess additional structural elements such as a time dynamics, or as an underlying graph structure that can be captured by natural dissimilarity measures such as alignment.There has been quite some effort to develop dimensionality reduction techniques for structures such as graph structures or time series, see, e.g., Ref 69 for a very promising graph drawing approach developed in the context of machine learning, or the