is.marked.ppp {spatstat.geom}

Test Whether A Point Pattern is Marked

Description

Tests whether a point pattern has “marks” attached to the points.

Usage

  ## S3 method for class 'ppp'
is.marked(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 if X is a marked point pattern.

Author(s)

Adrian Baddeley [e-mail] and Rolf Turner [e-mail]

See Also

is.marked, is.marked.ppm

Examples

   is.marked(cells)  #FALSE
   data(longleaf)
   is.marked(longleaf) #TRUE