Image                package:IDPmisc                R Documentation

_P_l_o_t_s _t_h_e _D_e_n_s_i_t_y _o_f _P_o_i_n_t_s _i_n _S_c_a_t_t_e_r _P_l_o_t _a_s _I_m_a_g_e

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

     The density of points in a scatter plot is encoded by color.

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

     Image(x, y, pixs = 1, zmax = NULL, colramp = IDPcolorRamp)

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

    x, y: Coordinates of points whose density should be plotted.

    pixs: Size of pixel in mm on the plotting device.

    zmax: Maximum counts per Pixel to be plotted. When NULL the density
          in the scatter plot is encoded from 0/pixel to maximum/pixel
          found. 'zmax' must be equal or larger than maximum counts
          found.

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

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

     Before calling 'Image' a plot must have been created by, for
     example, calling 'plot(x,y,type="n")'. A similar solution for
     plotting densities is realized in the package 'fields': 
     'image.count'. The main differences between the solution in
     'IDPmisc' and 'fields' are the following: In 'Image' the pixel
     size is defined in mm on the plotting device whereas in 
     'image.count' the number of pixels in x- and y-direction are
     defined. 'Image' works on ordinary plots whereas  'image.count'
     needs the special plotting function 'image.plot'.

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

     Maximum number of counts per Pixel found.

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

     Andreas Ruckstuhl, refined by Rene Locher

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

     'ipairs', 'ilagplot', 'ixyplot', 'image', 'image.count'

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

     x <- rnorm(10000)
     y <- rnorm(10000,10)
     plot(x+y,y,type="n")
     Image(x+y,y)

