
Poisson Models 329
x -0.8031 0.05863 -0.9180 -0.6882 *** -13.698
y 0.6496 0.11571 0.4228 0.8764 *** 5.614
This is the fitted model w ith intensity fun ction
λ
θ
((x,y)) = exp(
θ
0
+
θ
1
x +
θ
2
y) (9.28)
where spatial coordinates x and y are measured in kilometres and, for example, the estimate of
θ
1
is
ˆ
θ
1
= −0.8031 with standa rd error se(
ˆ
θ
1
) = 0.05863 and 95% confidence interval [−0.918,−0.6882].
The amount of information displayed, and the layout, depend on spatstat.options('terse')
and spatstat.options('print.ppm.SE').
The fitted coefficients of the model can be extracted by coef.ppm, a method for the generic
function coef:
> coef(fitkm)
(Intercept) x y
9.0910 -0.8031 ...