

   IIddeennttiiffyy PPooiinnttss iinn aa SSccaatttteerr PPlloott

        identify(x, ...)
        identify.default(x, y = NULL, labels = seq(along = x), pos = FALSE,
              n = length(x), plot = TRUE, offset = 0.5, ...)

   AArrgguummeennttss::

        x,y: coodinates of points in a scatter plot.  Alterna-
             tively, any object which defines coordinates (a
             plotting structure, time series etc.) can be given
             as `x' and `y' left undefined.

     labels: an optional vector, the same length as `x' and
             `y', giving labels for the points.

        pos: if `pos' is `TRUE', a component is added to the
             return value which indicates where text was plot-
             ted relative to each identified point (1=below,
             2=left, 3=above and 4=right).

          n: the maximum number of points to be identified.

       plot: if `plot' is `TRUE', the labels are printed at the
             points and if `FALSE' they are omitted.

     offset: the distance (in character widths) which separates
             the label from identified points.

        ...: further arguments to `par(.)'.

   DDeessccrriippttiioonn::

        `identify' reads the position of the graphics pointer
        when the (first) mouse button is pressed.  It then
        searches the coordinates given in `x' and `y' for the
        point closest to the pointer.  If this point is close
        to the pointer, its index will be returned as part of
        the value of the call.

   DDeettaaiillss::

        If in addition, `plot' is `TRUE', the point is labelled
        with the corresponding element of `text'.

        The labels are placed either below, to the left, above
        or to the right of the identified point, depending on
        where the cursor was.

        The identification process is terminated by pressing
        any mouse button other than the first, or by clicking
        outside the graphics window.

   VVaalluuee::

        If `pos' is `FALSE', an integer vector containing the
        indexes of the identified points.

        If `pos' is `TRUE', a list containing a component
        `ind', indicating which points were identified and a
        component `pos', indicating where the labels were
        placed relative to the identified points.

