is.marked.ppp
Test Whether A Point Pattern is Marked
Tests whether a point pattern has ``marks'' attached to the points.
- Keywords
- spatial
Usage
is.marked.ppp(X, na.action="warn", ...)
Arguments
- X
- Point pattern (object of class
"ppp"
) - na.action
- String indicating what to do if
NA
values are encountered amongst the marks. Options are"warn"
,"fatal"
and"ignore"
. - ...
- Ignored.
Details
``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;
the 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 X
contains or involves marked points.
It is a method for the generic function is.marked
.
The argument na.action
determines what action will be taken
if the point pattern has a vector of marks but some or all of the
marks are NA
. Options are "fatal"
to cause a fatal
error; "warn"
to issue a warning and then return TRUE
;
and "ignore"
to take no action except returning TRUE
.
Value
- Logical value, equal to
TRUE
ifX
is a marked point pattern.
See Also
Examples
data(cells)
is.marked(cells) #FALSE
data(longleaf)
is.marked(longleaf) #TRUE