Test Whether A Point Pattern is Multitype
Tests whether a point pattern has ``marks'' attached to the points which classify the points into several types.
## S3 method for class 'ppp': is.multitype(X, na.action="warn", \dots)
- Point pattern (object of class
- String indicating what to do if
NAvalues are encountered amongst the marks. Options are
``Marks'' are observations attached to each point of a point pattern.
For example the
longleaf dataset 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.
This function tests whether the point pattern
contains or involves marked points, and that the
marks are a factor.
It is a method for the generic function
For example, the
dataset is multitype (there are two types of cells, on and off),
longleaf dataset is not multitype
(the marks are real numbers).
na.action determines what action will be taken
if the point pattern has a vector of marks but some or all of the
NA. Options are
"fatal" to cause a fatal
"warn" to issue a warning and then return
"ignore" to take no action except returning
- Logical value, equal to
Xis a multitype point pattern.
data(cells) is.multitype(cells) #FALSE - no marks data(longleaf) is.multitype(longleaf) #FALSE - real valued marks data(amacrine) is.multitype(amacrine) #TRUE