arrows               package:graphics               R Documentation

_A_d_d _A_r_r_o_w_s _t_o _a _P_l_o_t

_D_e_s_c_r_i_p_t_i_o_n:

     Draw arrows between pairs of points.

_U_s_a_g_e:

     arrows(x0, y0, x1, y1, length = 0.25, angle = 30, code = 2,
            col = par("fg"), lty = NULL, lwd = par("lwd"), xpd = NULL)

_A_r_g_u_m_e_n_t_s:

  x0, y0: coordinates of points *from* which to draw.

  x1, y1: coordinates of points *to* which to draw.

  length: length of the edges of the arrow head (in inches).

   angle: angle from the shaft of the arrow to the edge of the arrow
          head.

    code: integer code, determining _kind_ of arrows to be drawn.

col, lty, lwd, xpd: graphical parameters as in 'par'.

_D_e_t_a_i_l_s:

     For each 'i', an arrow is drawn between the point '(x0[i], y0[i])'
     and the point '(x1[i],y1[i])'.

     If 'code=1' an arrowhead is drawn at '(x0[i],y0[i])' and if
     'code=2' an arrowhead is drawn at '(x1[i],y1[i])'.  If 'code=3' a
     head is drawn at both ends of the arrow.  Unless 'length = 0',
     when no head is drawn.

     The graphical parameters 'col', 'lty' and 'lwd' can be vectors of
     length greater than one and will be recycled if necessary. 'NA'
     values of 'col' are replaced by 'par("col")'.

     The direction of a zero-length arrow is indeterminate, and hence
     so is the direction of the arrowheads.  To allow for rounding
     error, arrowheads are omitted (with a warning) on any arrow of
     length less than 1/1000 inch.

_N_o_t_e:

     The first four arguments in the comparable S function are named
     'x1,y1,x2,y2'.

_R_e_f_e_r_e_n_c_e_s:

     Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) _The New S
     Language_. Wadsworth & Brooks/Cole.

_S_e_e _A_l_s_o:

     'segments' to draw segments.

_E_x_a_m_p_l_e_s:

     x <- runif(12); y <- rnorm(12)
     i <- order(x,y); x <- x[i]; y <- y[i]
     plot(x,y, main="arrows(.) and segments(.)")
     ## draw arrows from point to point :
     s <- seq(length(x)-1)# one shorter than data
     arrows(x[s], y[s], x[s+1], y[s+1], col= 1:3)
     s <- s[-length(s)]
     segments(x[s], y[s], x[s+2], y[s+2], col= 'pink')

