  The Oja median is one of several extensions of the univariate median to the
multivariate case. It has many nice properties, but is computationally
demanding. In this paper, we first review the properties of the Oja median and
compare it to other multivariate medians. Afterwards we discuss four algorithms
to compute the Oja median, which are implemented in our R-package OjaNP.
Besides these algorithms, the package contains also functions to compute Oja
signs, Oja signed ranks, Oja ranks, and the related scatter concepts. To
illustrate their use, the corresponding multivariate one- and $C$-sample
location tests are implemented.
