Test Whether Marks Are Present
Generic function to test whether a given object (usually a point pattern or something related to a point pattern) has ``marks'' attached to the points.
Object to be inspected
``Marks'' are observations attached to each point of a point pattern.
For example the
contains the locations of trees, each tree being marked by its diameter;
amacrine dataset gives the locations of cells
of two types (on/off) and the type of cell may be regarded as a mark attached
to the location of the cell.
Other objects related to point patterns, such as point process models, may involve marked points.
This function tests whether the object
contains or involves marked points.
It is generic; methods are provided
for point patterns (objects of class
and point process models (objects of class
Logical value, equal to
X is marked.