MultiStraussHard          package:spatstat          R Documentation

_T_h_e _M_u_l_t_i_t_y_p_e/_H_a_r_d _C_o_r_e _S_t_r_a_u_s_s _P_o_i_n_t _P_r_o_c_e_s_s _M_o_d_e_l

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

     Creates an instance of the multitype/hard core Strauss point
     process model which can then be fitted to point pattern data.

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

       MultiStraussHard(types, iradii, hradii)

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

   types: Vector of all possible types (i.e. the possible levels of the
          'marks' variable in the data)

  iradii: Matrix of interaction radii

  hradii: Matrix of hard core radii

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

     This is a hybrid of the multitype Strauss process (see
     'MultiStrauss') and the hard core process (case gamma = 0 of the
     Strauss process). A pair of points of types i and j must not lie
     closer than h[i,j] units apart; if the pair lies more than h[i,j]
     and less than  r[i,j] units apart, it contributes a factor
     gamma[i,j] to the probability density.

     The matrices 'iradii' and 'hradii' must be symmetric, with entries
     which are either positive numbers or 'NA'.  A value of 'NA'
     indicates that no interaction term should be included for this
     combination of types.

     Note that only the interaction radii and hardcore radii are
     specified in 'MultiStraussHard'. The canonical parameters
     log(beta[j]) and log(gamma[i,j]) are estimated by 'ppm()', not
     fixed in 'MultiStraussHard()'.

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

     An object of class '"interact"' describing the interpoint
     interaction structure of the multitype/hard core Strauss process
     with interaction radii iradii[i,j] and hard core radii
     hradii[i,j].

_W_a_r_n_i_n_g_s:

     The argument 'types' is interpreted as a set of factor levels.
     That is, in order that 'ppm' can fit the multitype Strauss model
     correctly to a point pattern 'X', this must be a marked point
     pattern; the mark vector 'X$marks' must be a factor; and  the
     argument 'types' must equal 'levels(X$marks)'.

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

     Adrian Baddeley adrian@maths.uwa.edu.au <URL:
     http://www.maths.uwa.edu.au/~adrian/> and Rolf Turner
     rolf@math.unb.ca <URL: http://www.math.unb.ca/~rolf>

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

     'ppm', 'pairwise.family', 'ppm.object', 'MultiStrauss', 'Strauss'

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

        r <- matrix(3, nrow=2,ncol=2)
        h <- matrix(c(1,2,2,1), nrow=2,ncol=2)
        MultiStraussHard(1:2, r, h)
        # prints a sensible description of itself
        data(betacells)
        r <- 30.0 * matrix(c(1,2,2,1), nrow=2,ncol=2)
        h <- 30.0 * matrix(c(NA,1,1,NA), nrow=2,ncol=2)
        ppm(betacells, ~1, MultiStraussHard(c("off","on"), r, h), rbord=60.0)
        # fit the stationary multitype hardcore Strauss process to `betacells'

