The owls are not what they seem - marked point processes from a different perspective
Data structures that detail the locations of objects or events in space,
i.e. spatial point patterns, are relevant in a wide range of applications – notably
in the context of ecology and environmental sciences but are equally relevant
elsewhere, e.g. in geophysics or terrorism studies. It is hence not surprising that
there have been many advances in spatial point process methodology recently,
enabling increasingly complex models to be formulated and fitted. These capture
the spatial structures inherent in point patterns with a focus on making them
relevant in applications.
In particular, practical relevance increases when the objects are no longer merely
regarded as points in space but as objects with properties. This implies that
information on attributes of the objects represented by the points is included in
a model in addition to their spatial location. Referred to as “marks”, these data
on, e.g., the size or the type of the object may provide an improved understanding
of spatial structures if included in an analysis. They may not only help explaining
the spatial structure formed by the objects, but may themselves exhibit a spatial
structure of interest that varies with the spatial structure of the locations. What
is more, this dependence between marks and pattern might be of interest in itself.
Hence elements in a model representing that dependence are no longer “nuisance
parameters”; their structure is relevant and interpretable in the context of the
In this talk we discuss a number of applications where flexible marked point
process models are particularly relevant – be it because there is a specific interest
in interpreting the mark structure or be it because interpreting a data structure
as a marked point pattern may account for complex observation processes.