axis                  package:base                  R Documentation

_A_d_d _a_n _A_x_i_s _t_o _a _P_l_o_t

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

     Adds an axis to the current plot, allowing the specification of
     the side, position, labels, and other options.

_U_s_a_g_e:

     axis(side, at = NULL, labels = TRUE, tick = TRUE, line = 0,
          pos = NA, outer = FALSE, font = NA, vfont = NULL,
          lty = "solid", lwd = 1, col = NULL, ...)

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

    side: an integer specifying which side of the plot the axis is to
          be drawn on.  The axis is placed as follows: 1=below, 2=left,
          3=above and 4=right.

      at: the points at which tick-marks are to be drawn.  Non-finite
          (infinite, `NaN' or `NA') values are omitted.  By default,
          when `NULL', tickmark locations are computed, see Details
          below.

  labels: this can either be a logical value specifying whether
          (numerical) annotations are to be made at the tickmarks, or a
          vector of character strings to be placed at the tickpoints.

    tick: a logical value specifying whether tickmarks should be drawn

    line: the number of lines into the margin which the axis will be
          drawn.  This overrides the value of the graphical parameter
          `mgp[3]'.  The relative placing of tickmarks and tick labels
          is unchanged.

     pos: the coordinate at which the axis line is to be drawn. this
          overrides the value of both `line' and `mgp[3]'.

   outer: a logical value indicating whether the axis should be drawn
          in the outer plot margin, rather than the standard plot
          margin.

    font: font for text.

   vfont: vector font for text.

lty, lwd: line type, width for the axis line and the tick marks.

     col: color for the axis line and the tick marks.  The default
          `NULL' means to use `par("fg")'.

     ...: other graphical parameters may also be passed as arguments to
          this function, e.g., `las' for vertical/horizontal label
          orientation, or `fg' instead of `col', see `par' on these.

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

     The axis line is drawn from the lowest to the highest value of
     `at', but will be clipped at the plot region. Only ticks which are
     drawn from points within the plot region (up to a tolerance for
     rounding error) are plotted, but the ticks and their labels may
     well extend outside the plot region.

     When `at = NULL', pretty tick mark locations are computed
     internally, from `par("usr","lab")', and `par("xlog")' (or `ylog'
     respectively).

_V_a_l_u_e:

     This function is invoked for its side effect, which is to add an
     axis to an already existing plot.

_E_x_a_m_p_l_e_s:

     plot(1:4, rnorm(4), axes=FALSE)
     axis(1, 1:4, LETTERS[1:4])
     axis(2)
     box() #- to make it look "as usual"

     plot(1:7, rnorm(7), main = "axis() examples",
          type = "s", xaxt="n", frame = FALSE, col = "red")
     axis(1, 1:7, LETTERS[1:7], col.axis = "blue")
     # unusual options:
     axis(4, col = "violet", col.axis="dark violet",lwd = 2)
     axis(3, col = "gold", lty = 2, lwd = 0.5)

