vgram                package:funfits                R Documentation

_V_a_r_i_o_g_r_a_m

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

     vgram(loc, y, lon.lat=F)

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

     loc: Matrix where each row is the coordinates of an observed point
          of the field 

       y: Value of the field at locations 

 lon.lat: If true, locations are assumed to be longitudes and latitudes
          and distances found are great circle distances. Default is
          false. 

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

     Object of class vgram.  This is list with components d the
     pairwise distances , vgram the value of the variogram and loc the
     locations.

_R_e_f_e_r_e_n_c_e_s:

     See any standard reference on spatial statistics. For example
     Cressie Spatial Statistics

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

     # compute variogram for the Chicago ozone field
     vgram( ozone$x, ozone$y, lon.lat=T)-> out
     plot( out$d, out$vgram, xlab="Distance", ylab="Squared differences")

