ABSTRACT
A spatial point process is a stochastic mechanism that generates a countable set of events xi in the plane. We will usually be dealing with processes that are stationary and isotropic. Stationarity means that all properties of the process are invariant under translation, isotropy that they are invariant under rotation. These assumptions are less restrictive than they might seem at first sight. In particular, they do not rule out the modelling of random heterogeneity in the environment (recall the discussion of Figure 1.2 in Section 1.1). However, three qualifications are in order.
