Test Whether A Point Pattern is Marked
Tests whether a point pattern has ``marks'' attached to the points.
## S3 method for class 'ppp': is.marked(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.
It is a method for the generic function
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 marked point pattern.
data(cells) is.marked(cells) #FALSE data(longleaf) is.marked(longleaf) #TRUE