

identify {base}                              R Documentation

_I_d_e_n_t_i_f_y _P_o_i_n_t_s _i_n _a _S_c_a_t_t_e_r _P_l_o_t

_D_e_s_c_r_i_p_t_i_o_n_:

     `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.

_U_s_a_g_e_:

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

_A_r_g_u_m_e_n_t_s_:

     x,y: coordinates 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(.)'.

_D_e_t_a_i_l_s_:

     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.

_V_a_l_u_e_:

     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.

