Ghat                 package:splancs                 R Documentation

_G _n_e_a_r_e_s_t _n_e_i_g_h_b_o_u_r _d_i_s_t_r_i_b_u_t_i_o_n _f_u_n_c_t_i_o_n

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

     Calculates an estimate of the G nearest neighbour distribution
     function.

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

     Ghat(pts,s)

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

     pts: A points data set 

       s: A vector of distances at which to evaluate the G function 

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

     The function 'Ghat(pts,s)' is defined as the proportion of members
     of a point set for which the distance to the nearest other member
     of the set is less than or equal to 's'.

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

     A vector of the same length as 's', containing the estimate of G
     at the  distances in 's'.

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

     Rowlingson, B. and Diggle, P. 1993 Splancs: spatial point pattern
     analysis code in S-Plus.  Computers and Geosciences, 19, 627-655;
     the original sources can be accessed at: <URL:
     http://www.maths.lancs.ac.uk/~rowlings/Splancs/>. See also Bivand,
     R. and Gebhardt, A. 2000 Implementing functions for spatial
     statistical analysis using the R language. Journal of Geographical
     Systems, 2, 307-317.

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

     'Fhat', 'nndistG'

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

     data(uganda)
     plot(seq(20, 500, 20), Ghat(as.points(uganda), seq(20, 500, 20)), 
     type="l", xlab="distance", ylab="Estimated G")

