ixyplot               package:IDPmisc               R Documentation

_I_m_a_g_e _S_c_a_t_t_e_r _P_l_o_t _f_o_r _L_a_r_g_e _D_a_t_a_s_e_t_s

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

     Produces an image scatter plot of large datasets where the colors
     encode the density of the points in the scatter plot. Works also
     with factors.

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

     ixyplot(x, y = NULL,
             pixs = 1, zmax = NULL, colramp = IDPcolorRamp, border = FALSE,
             xlab = NULL, ylab = NULL, nx.lab = 5, ny.lab = 5,
             main = NULL, cex.main = par("cex.main"))

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

       x: Object of dimension (n,1) or (n,2) when y not present. 
          Vector of length(n) when y present.

       y: Vector of length n or 'NULL'.

    pixs: Pixelsize in mm.

    zmax: Maximum counts per pixel to be plotted. 'zmax' must be >=
          maximum number of counts per pixel.

 colramp: Color ramp to encode the density of the points within a
          pixel.

  border: Shall border be drawn between the colors in the legend:
          'TRUE' / 'FALSE'.

    xlab: Label for x-axis.

    ylab: Label for y-axis.

  nx.lab: Approximate number of labeled ticks on x-axis.

  ny.lab: Approximate number of labeled ticks on y-axis.

    main: Title.

cex.main: Size of title relative to 'par("cex")'

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

     The idea is similar to 'plot.hexbin'. The hexagons are better
     suited to reflect the density of points in a plane than the
     squares used here. Nevertheless squares are, contrary to hexagons,
     invariant to reflexions at the x- _and_ y-axis and therefore
     suited for scatter plot matrices and also for plotting factors.

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

     Maximum number of counts per Pixel found.

_N_o_t_e:

     When you get the error message "Zmax too small! Densiest aereas
     are out of range!" you must run the function again without
     specifying zmax. The value returned gives you the minimum value
     allowed for zmax.

_A_u_t_h_o_r(_s):

     Andreas Ruckstuhl, refined by Rene Locher

_S_e_e _A_l_s_o:

     'ilagplot', 'ipairs', 'Image'

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

     x <-  rnorm(100000)
     y <- atan(rnorm(100000,0))
     ixyplot(x,y)
     ixyplot(x,pixs=2)
     ixyplot(iris[,1:2],pixs=4)
     ixyplot(iris[,"Petal.Width"],iris[,"Species"],pixs=4)
     ixyplot(x=iris[,"Species"],y=iris[,"Petal.Width"],pixs=4,border=TRUE,
             xlab="Species",
             ylab="Petal Width",
             main="Iris Species and Petal Width")

