affine               package:spatstat               R Documentation

_A_p_p_l_y _A_f_f_i_n_e _T_r_a_n_s_f_o_r_m_a_t_i_o_n

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

     Applies any affine transformation of the plane (linear
     transformation plus vector shift) to a plane geometrical object,
     such as a point pattern or a window.

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

      affine(X, mat=diag(c(1,1)), vec=c(0,0))

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

       X: Any suitable dataset representing a two-dimensional object,
          such as a point pattern (object of class '"ppp"'), or a
          window (object of class '"owin"').

     mat: Matrix representing a linear transformation.

     vec: Vector of length 2 representing a translation.

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

     This is generic. Methods are provided for point patterns
     ('affine.ppp') and windows ('affine.owin').

     First the linear transformation represented by 'mat' is applied
     (multiplying on the left by 'mat'), and then the result is
     translated by the vector 'vec'.

     The argument 'mat' must be a nonsingular 2 * 2 matrix.

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

     Another object of the same type, representing the result of
     applying the affine transformation.

_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:

     'affine.ppp', 'affine.owin', 'rotate', 'shift'

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

       data(cells)
       # shear transformation
       X <- affine(cells, matrix(c(1,0,0.6,1),ncol=2))
       ## Not run: 
       plot(X)
       # rescale y coordinates by factor 1.3
       plot(affine(cells, diag(c(1,1.3))))
       
     ## End(Not run)

