lowres              package:adehabitat              R Documentation

_R_e_d_u_c_i_n_g _t_h_e _R_e_s_o_l_u_t_i_o_n _o_f _a _M_a_p

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

     'lowres' is a generic function, having methods for the classes
     'asc' and 'kasc'. It is used to reduce the resolution of the maps.

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

     lowres(x, np = 2, ...)

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

       x: an object of class 'asc' or 'kasc'

      np: a number giving the number of pixels to merge together (see
          below)

     ...: further arguments passed to or from other methods

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

     The function merges together squares of 'np * np' pixels.  For
     maps of type '"numeric"' (see 'help(as.asc)'), the function
     averages the value of the variable. For maps of type '"factor"',
     the function gives the most frequent level in the square of 'np *
     np' pixels.  When several levels are equally represented in the
     square of 'np * np' pixels, the function randomly samples one of
     these levels.

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

     Returns an object of class 'asc' or 'kasc'.

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

     Clment Calenge calenge@biomserv.univ-lyon1.fr

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

     'as.asc', 'as.kasc'

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

     data(puechabon)
     kasc <- puechabon$kasc

     ## The initial image
     image(kasc)

     ## The transformed image
     m <- lowres(kasc, np = 4)
     image(m)

