data(humberside)humberside 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 case and control
indicating whether this is a disease case
or a control.
}
See ppp.object for details of the format. The dataset humberside.convex is an object of the
same format, representing the same point pattern data,
but contained in a larger, 5-sided convex polygon.
The data record 62 cases of childhood leukaemia and lymphoma diagnosed in the North Humberside region of England between 1974 and 1986, together with 141 controls selected at random from the birth register for the same period.
The data are represented as a marked point pattern, with the points giving the spatial location of each individual's home address (actually, the centroid for the postal code) and the marks identifying cases and controls.
Coordinates are in multiples of 100 metres, and the resolution is 100 metres.
Two versions of the dataset are supplied, both containing the
same point coordinates, but using different windows.
The dataset humberside has a polygonal window with 102 edges
which closely approximates the Humberside region,
while humberside.convex has a convex 5-sided polygonal window
originally used by Diggle and Chetwynd (1991) and shown in
Figure 1 of that paper.
P.J. Diggle and A.G. Chetwynd (1991) Second-order analysis of spatial clustering for inhomogeneous populations. Biometrics 47 (1991) 1155-1163.