chorley               package:spatstat               R Documentation

_C_h_o_r_l_e_y-_R_i_b_b_l_e _C_a_n_c_e_r _D_a_t_a

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

     Spatial locations of cases of cancer of the larynx and cancer of
     the lung, and the location of a disused industrial incinerator. A
     marked point pattern.

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

     data(chorley)

_F_o_r_m_a_t:

     The dataset 'chorley' is an object of class '"ppp"' representing a
     marked point pattern. Entries include

       'x'      Cartesian x-coordinate of home address
       'y'      Cartesian y-coordinate of home address
       'marks'  factor with levels 'larynx' and 'lung'
                indicating whether this is a case of cancer of the larynx
                or cancer of the lung.

     See 'ppp.object' for details of the format.

     The dataset 'chorley.extra' is a list with two components. The
     first component 'plotit' is a function which will  plot the data
     in a sensible fashion. The second component 'incin' is a list with
     entries 'x' and 'y' giving the location of the industrial
     incinerator.

     Coordinates are in multiples of 1 kilometre,  and the resolution
     is 100 metres.

_N_o_t_e_s:

     The data give the precise domicile addresses of new cases  of
     cancer of the larynx (58 cases) and cancer of the lung (978
     cases), recorded in the Chorley and South Ribble Health Authority
     of Lancashire (England) between 1974 and 1983. The supplementary
     data give the location of a disused industrial incinerator.

     The data were first presented and analysed by Diggle (1990). They
     have subsequently been analysed by Diggle and Rowlingson (1994)
     and Baddeley et al. (2005).

     The aim is to assess evidence for an increase in the incidence of
     cancer of the larynx in the vicinity of the now-disused industrial
     incinerator. The lung cancer cases serve as a surrogate for the
     spatially-varying density of the susceptible population.

     The data are represented as a marked point pattern, with the
     points giving the spatial location of each individual's home
     address and the marks identifying whether each point is a case of
     laryngeal cancer or lung cancer.

     Coordinates are in multiples of 1 kilometre, and the resolution is
     100 metres.

     The dataset 'chorley' has a polygonal window with 132 edges which
     closely approximates the boundary of the Chorley and South Ribble
     Health Authority.

_S_o_u_r_c_e:

     Coordinates of cases were provided by the Chorley and South Ribble
     Health Authority, and were kindly supplied by Professor Peter
     Diggle. Region boundary was digitised by Adrian Baddeley, 2005,
     from a photograph of an Ordnance Survey map.

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

     Baddeley, A., Turner, R., Moller, J. and Hazelton, M. (2005)
     Residual analysis for spatial point processes. Journal of the
     Royal Statistical Society, series B. to appear.

     Diggle, P. (1990) A point process modelling approach to   raised
     incidence of a rare phenomenon in the vicinity of a prespecified
     point. _Journal of the Royal Statistical Soc. Series A_  *153*,
     349-362.

     Diggle, P. and Rowlingson, B. (1994) A conditional approach to
     point process modelling of elevated risk. _Journal of the Royal
     Statistical Soc. Series A_  *157*, 433-440.

